Top 10 Problems When Using Regulating Valves

1. Why is the two-seat valve prone to oscillation when working under small opening conditions?

For single-core valves, when the medium is flow-open type, they’re stable. When the medium is flow-closed type, they’re unstable. There’re two valve cores in the two-seat valve. The lower core is in flow-closed condition while the upper core is in flow-open condition. In this case, under small opening conditions, the flow-closed type of valve core will easily cause oscillation of the valve. This is why two-seat valves can be used for small opening conditions.

2. Why can’t double-sealing valves be used as sanitary shut-off valves?

Two-seat valve core has the advantage of balanced force double-sealing valve structure, allowing a large pressure difference. And its shortcoming is that the two sealing surfaces cannot be in good contact at the same time, causing a large leakage. If it’s purposefully and mandatorily used in shut-off occasions, the effect won’t be good, even if a lot of improvements have been made on it. (such as double-sealing sleeve valve)

3. Why does the straight stroke sanitary regulating valve have a poor anti-blocking performance and rotary stroke regulating valve have a good anti-blocking performance?

The core of straight stroke valve is vertical throttle, but the flow direction of the medium is horizontal. So there must be lots of twists and turns in valve cavity flow channel, making the flow paths of the valve very complex. Therefore, there’re a lot of blind zones that provide space for deposition of the medium, which in the long run causes clogging. The throttle direction of rotary stroke valve is horizontal, the medium horizontally flows in and out, which can easily take away unclean medium. Meanwhile, the flow path is simple, and there’s little room for medium deposition, so rotary stroke valve has a good anti-blocking performance.

4. Why is the stem of straight stroke regulating valve thin?

It involves a simple mechanical principle: the bigger the sliding friction, the smaller the rolling friction. The stem of straight stroke valve moves up and down. If the stuffing slightly pressed a little tighter, it would wrap up the stem tightly, resulting in a large hysteresis. To this end, the valve stem is designed to be thin and small and the stuffing use PTFE that has a small friction coefficient in order to reduce the hysteresis. But the problem that derives from this is that a thin valve stem is easy to bend and the stuffing has a short service life. To solve the problem, the best way is to use rotary valve stem, a regulating valve similar to the rotary stroke ones. Its valve stem is 2 to 3 times thicker than that of the straight stroke valve. And it uses graphite stuffing that has a long service life. The valve stem stiffness is good, the service life of stuffing is long, the friction torque and hysteresis are instead small.

5. Why does the rotary stroke valve have a relatively large shut-off pressure difference?

It’s because the torque on the rotating shaft produced by the force of medium on valve core or valve plate is very small.

6. Why is the service life of desalination water medium short when using rubber lined butterfly valve and fluorine lined diaphragm valve?

The medium of desalination water contains low concentrations of acid or alkali, which are pretty corrosive to rubber. The corrosion of rubber is exemplified by expansion, aging and low strength. The poor effect of using rubber lined butterfly valve and diaphragm valve is actually caused by the intolerance of corrosion of rubber. Rear rubber-lined diaphragm valve is improved to be the fluorine lined diaphragm valve that has a good tolerance of corrosion. But the lining of diaphragm of fluorine lined diaphragm valve can’t withstand the up-and-down folding and is broken, resulting in mechanical damage and shorter service life of the valve. Now the best way is to use water treatment special ball valves, which can be used for 5 to 8 years.

7. Why should shut-off valves try to use hard sealing?

Sanitary shut-off valves require the leakage to be as low as possible. The leakage of soft sealing valve is the lowest, so the shut-off effect is certainly good. But it’s not wear-resistant, not reliable. Judging from the double standard of small leakage and reliable sealing, soft sealing shut-off is not as good as hard sealing shut-off. Take full-featured ultra-light regulating valve for example, it’s sealed and piled with wear-resistant alloy for protection, highly reliable, has a leakage rate of 10 to 7, all of which already have met the requirements of shut-off valves.

8. Why can’t sleeve valves replace single-seat and double-seat valves?

Sleeve valves, which first appeared in the ’60s, were widely used in the ’70s worldwide. Sleeve valves account for a large percentage in petrochemical equipment imported during the ’80s. At that time, many people thought sleeve valves could replace single-seat and double-seat valves to become the second-generation products. Until now, that is not the case. Single-seat valves, double-seat valves and sleeve valves are equally used. That’s because sleeve valves only improve the way of throttle, have better stability and maintenance than single-seat valves. But its weight, anti-blocking and leakage indicator are the same as those of single-seat and double-seat valves.

9. Why is selection more important than computation?

Compare computation with selection, selection is more important and more complicated. Computation is only a simple formula. It’s not the formula itself, but rather the accuracy of given parameters that matters. Selection involves a lot of things, being a bit careless will lead to improper selection, which not only results in the waste of manpower, material, and money, but the effects of use are not good, causing a number of problems in use, such as reliability, service life and quality, etc.

10. Why is piston actuator increasingly used in pneumatic valves?

For pneumatic valves, the piston actuator can make full use of air pressure to make the size of the actuator smaller than that of the film type. The thrust is bigger. The O-ring in the piston is also more reliable than that of the film. All in all, it’s increasingly used.

Best Characteristics of Carbon Steel Pipe Fittings

Before choosing which type of metal to use for an industrial project, the first thing that you should consider is the magnitude and scale of the task, what type of liquid or gas the pipes will be carrying and the longevity of structure. Once that has been established, you can then answer questions to what type of metal to use for the piping.

For example, due to its strength and versatility, steel is one of the most popular materials used for pipe and pipe fittings. Even better, different material, like carbon or chrome, can be added to steel to obtain a specific desired effect. Here are a few reasons why it may be beneficial to invest in carbon steel pipe fittings and valves for your next commercial project.

1. Super Strength

Because of its strength and durability, steel has been one of the most commonly used materials for industrial piping and other types of construction. However, with the addition of carbon to the already strong metal, it has the ability to turn into a much stronger product. By undergoing heat treatment, the strength can be increased without altering the shape – and the more carbon added to the metal, the more durable it can become. This has made carbon steel pipe fittings, valves and pipes some of the most durable industrial piping products available. For companies interested in increasing the strength of their pipes, carbon pipe suppliers can offer the necessary supplies.

2. Morphing Power

With just the right amount of carbon added to the steel, it’s easier to get the exact level of durability necessary for each unique project. For example, mild carbon steel is one of the most popular options because it’s cost efficient for large-scale projects. Medium carbon steel is more often used in the construction of automobiles because it’s more resistant to eroding elements. The higher the level of carbon, the stronger the steel becomes. This means that carbon steel products with the highest levels of carbon are mostly used in the production of wires. Once the carbon level exceeds 1.0 percent, it can only be used in very specific industrial projects. With so many different types of carbon steel to choose from, it can get confusing. Carbon pipe suppliers can help you determine which is best for your project.

3. Endurance

Endurance is a good word to describe carbon steel pipe fittings because they can endure environmental change and last for years. Great for household usage, carbon steel pipes are great for home sprinkler systems and can carry water, oil, steam and even flammable gasses. Because they are resistant to rust, that means much less cleaning for the homeowner and longevity for the pipes. Other uses for carbon steel pipes include shipbuilding, industrial construction and electric-power plants.

8 Tips To Prevent Pipes From Freezing

Do you have any idea as to what the Arctic Vortex is? Actually, this thing is responsible for bringing a lot of cold. In winter, if you have a frozen pipe problem, you may want to follow the tips given below to make sure that your pipes don’t freeze.

Be Prepared

It matters to get ready ahead of time. What you need to do is cut a few blocks of foam to seal the base vents. Also make sure you know the location of the water shutoff. This will help you deal with the situation in case you find a broken pipe. You may also want to have a temporary patch kit in order to seal the burst pipes. You can then wait for the right season to get it repaired. You should do you research to find out the best plumber to fix the pipes that have already been frozen.

Increase the thermostat

If your house is an old one and built over a non-insulated crawl space, you may want to increase the thermostat to raise the air temperature. This will keep all of the pipes from freezing.

Install Fiberglass

You should get some insulation of unfaced fiberglass. Moreover, you should get some disposable coveralls, work gloves, a dust mask and some knife blades. Once you have worn the gloves, you should figure out your insulation needs.

Use Foam Board

Do you want to protect a wide area? If so, you can use a barrier of foam board to retain the heat. You can also do with an unfaced or faced foam board if you want a temporary fix. You can use a sharpie or a pencil to mark the surface.

Install a Heating Cable

You should consider installing a heating cable. Before you do this, make sure you read the instruction manual. Some tapes run along the pipe and some are wrapped around it. At times, the cable needs to be cut so you need to opt for a kit to get it into the desired shape.

Use A Space Heater

You can put an electric heater close to the pipes to keep the cold away. Keep in mind that the purpose is not to keep the space comfortable. Instead, the goal is to keep the water in the pipes from freezing.

Turn The Water off

Another option is to turn the water off by closing the main valve, especially if you are not going to stay in the house. In case the pipes freeze, the spillage will be limited to the amount of water in the pipe.

Open Cabinet Doors

The pipes may be running to your exterior wall or the kitchen sink, and the pipes may be vulnerable since the wall is not usually insulated. To let the heat come in, you may want to open the doors of the cabinet along the wall. For extra protection, you can put the heater near the cabinets.

General Safety Tips To Stay Safe While Installing An Electrical Panel

Electrical panels have the core function to provide a constant supply of energy to all the sub circuits and it is essential to keep the safety notes at the time you install the device as to avoid any electrical hazard later. Thus, before you go to install the device, it is important to go through these points and ensure the proper safety of the whole system.

Tips To Stay Safe While Installing The Electrical Panel:-

  • Avoid Water – The water and electricity can never be together at the application, despite the fact electricity is generated from water. It is important to be on the safe side than curing the pain later. While you install the system, remember to keep it high enough from the reach of water. The equipment and circuit should have distance from the water as it increases the conductivity of electrical current.
  • Prevent Shocks – Apart from keeping the equipment away from the water, you should also pay attention to the bare wires. Uncovered wires are the main cause of electric current as if you touch the end by mistake. You can cover these ends with a cap so the insulator eliminates the direct contact with the copper and prevents getting a shock.
  • Check For Live Wires – Energized wires are the dangerous to death and checking for such wires regularly while working is better to save yourself from the hazards. Never assume that electrical equipment is uncharged even when left isolated for a long time. While installing the panel, check twice for any energized wires as to avoid the problems and to ensure there is no current running through them.
  • Overload Protection – The main reason of blasting of the panel is over loading and avoiding this point helps you to prevent the damages as well as danger to life. At the time, you install the panel for your industry, calculate the voltage requirement, and add a 25% surplus in that so you can be prepared for the next installations and you will not end up installing the device over again for every additional equipment.
  • Equipment Reliability – The electrical panel is designed to provide constant supply of power from the main circuits to the sub circuits. It necessary to maintain a good ratio of voltage supply with the basic requirements, therefore, always you should always remember to keep an eye on the ideal ratio to avoid any problems. If anytime you feel the panel tingly feeling, disconnect it as sooner as possible and stop using that at the time.

3D Printing: The Materials Used for 3D Printing

3D printing was developed back in the early 80s but it has seen much growth since the past 10 years. It has now become one of the biggest growth areas in the tech industry and is revolutionising manufacturing covering every industry possible. The 3D printing business is now multi-billion dollar industry and is likely to continue growing at an exponential rate.

3D printing is quite a simple process conceptually, the printers work by printing the chosen material in layers on top of each other, with each layer setting prior to the next pass of the printer.

3D printers have been used to print all sorts of materials from cheap and normal materials to things you would expect to read in a sci-fi book.

For the consumer market, plastics are used exclusively as the materials are cheap to buy, but more importantly, the technology required to print plastic is relatively simple and low cost.

Low-cost 3D printers using plastic tend to use Fused filament fabrication (FFF). This is basically a process where a cord of plastic is heated up to become pliable then fed through the machine layering the plastic. The machines generally use one of the following plastics

PLA (Polylactic Acid) – PLA is probably the easiest material to work with when you first start 3D printing. It is an environmentally friendly material that is very safe to use, as it is a biodegradable thermoplastic that has been derived from renewable resources such as corn starch and sugar canes. This is a similar plastic that is used in compostable bags which safely bio degrade compared to more traditional plastics used in Poly Bags.

ABS (Acrylonitrile butadiene styrene) – ABS is considered to be the second easiest material to work with when you start 3D printing. It’s very safe and strong and widely used for things like car bumpers, and Lego (the kid’s toy).

PVA (Polyvinyl Alcohol Plastic) – PVA plastic which is quite different to PVA Glue (please don’t try putting PVA Glue into your 3D Printer, it definitely won’t work). The popular MakerBot Replicator 2 printers use PVA plastic.

Plastics are used extensively on all levels from consumer to businesses prototyping new products. However, in the business market, there is a huge demand for metal 3D printing. Some printers can use powdered material that is then heated to create a solid. This method is typically Direct Metal Laser Sintering (DMLS) and this particular technique is why we don’t see consumer metal 3D printing. DMLS requires a huge amount of heat and giant expensive printers to sinter the material together, and while 3D printing a metal object might be expensive compared to mass production, it is incredibly cost efficient for complex and expensive projects. A good example of DMLS based 3D printing is GE Aviation using it to produce 35,000 fuel injectors for its LEAP jet engine.

Using boring materials such as metal is almost archaic in the world of 3D printing now; some companies now do 3D bioprinting which is the process of creating cell patterns in a confined space using 3D printing technologies, where cell function and viability are preserved within the printed construct. These 3D bioprinters have the capacity to print skin tissue, heart tissue, and blood vessels among other basic tissues that could be suitable for surgical therapy and transplantation.

Steel Cutting Machines

Steel is one of the major commonly used metals in the world. It comprises of Iron and Carbon alloy, and thus it is one of the strongest and hardest metals utilized in the building of infrastructures and industrial manufacture of metallic pieces, for example, car parts and machinery parts. It is resistant to rust, and it is easily bendable. There are many advantages associated with steel, and therefore the skills necessary to make use of it is widely known. From processing to making something out of the metal is critical value information.

Steel cutting is the process by which a steel material is cut and turned into a sizable, proper dimensional piece, fit for its use. Cutting of metal such as steel can be done through various methods and these includes;

· The manual cutting, hacksaw or any cutting hand operated tool, is used to cut the steel manually

· Cutting by machine, this is where machine such as grinders and drillers are used to cut into pieces or cut the core in metal.

· Laser technology. Laser beams burn and cut through the metal.

· Cutting using chemicals, specialized chemical reagents are used for specific metals.

· Erosion technique utilizes a mixture of water and abrasives at a very high force to erode off the metal thus cutting it into the preferred sizes.

The modern technology has embraced machine cutting technology due to its simplicity and precision. These devices also come with a programmable database to ensure that most processes are automated. Therefore, the end product is always appealing. Straight core cutting requires precision and accuracy, and therefore, a particular type of machine has been made for that purpose.

Properties of a Good Steel Core cutting machine;

· The tool should be easy to use and be automated in that, most processes can be adjustable, and any error corrected as soon as it arises.

· It should be able to cut the different core sizes by allowing fitting of different size cutting blades; the changing process should be easy.

· A good machine should require fewer maintenance services.

Conclusion.

Silicon steel commonly used magnetic core is preferred for its great unique energy conserving abilities. Therefore while cutting these cores into the steel metal to be used, care and accuracy are required. Only a good machine can help you in this. The above-listed properties should be considered by any metal factory while ordering and purchasing for the cutting machine; only genuine ones can provide the right services.

3 Keys to a Successful Preventive Maintenance Program

Preventive maintenance planning and practices influence most major maintenance department activities in a manufacturing environment. Here are some examples of this.

  • Equipment downtime is largely affected by preventive maintenance or the lack there of.
  • Repair work orders are subjected to the influences of the preventive maintenance program.
  • Purchasing and inventory are affected by preventive maintenance for routine replacement of expendable spares as well as repair parts required for unexpected downtime.

As evidenced by the points above, preventive maintenance should be “first base” for any maintenance department. Unfortunately sometimes routine preventive maintenance activities often do not get the attention or credit they are due. This is a mistake. So what are the keys to a successful preventive maintenance program?

1. Careful Planning of the Preventive Maintenance Program

Planning a preventive maintenance program involves the following:

  1. Determine tasks and intervals needed to maintain the equipment.
  2. Ensure that the appropriate resources are in place.
    • Schedule maintenance personnel for maximum preventive maintenance wrench time.
    • Understand how scheduled equipment downtime and maintenance personnel scheduling interface.
    • Manage spares effectively.
  3. Select a scheduling and accountability system (preventive maintenance software, CMMS software or equivalent)

Determine Maintenance Tasks and Intervals

A good preventive maintenance (PM) task list contains the following components:

  • The equipment item.
  • The task(s).
  • The person the task is assigned to.
  • A task interval.
  • A start date and due date.
  • Optional: Detailed instructions and pictures if needed.
  • Optional: Task completion sequence.

Begin with your equipment list. Next gather appropriate tasks for preventive maintenance task lists from OEM manuals or online manuals when possible. This is a good place to start, especially with newer equipment. In some cases, the equipment warranty is dependent upon following the OEM recommendations. Another source of tasks is the maintenance manager’s experience and intuition. Yet another source is branch locations running similar equipment.

When developing a task list, consider the reusability of the task descriptions. Reusability refers to using the same task description on potentially multiple equipment items. The benefit is that there are fewer tasks, no duplicate task descriptions and better reporting and analysis of PMs. Consider these examples:

REUSABLE task description: Lubricate Roller Chain(s)

NOT REUSABLE: Lubricate Roller Chain(s) on Conveyor #1

In the first example this task, Lubricate Roller Chain(s), is appropriate for any equipment with a roller chain. In the second example, Lubricate Roller Chain on Conveyor #1, is only appropriate on the Conveyor #1 PM task list. Imagine how cumbersome your preventive maintenance software management efforts become if you are not using reusable tasks. Another example that may cause problems later is naming conventions such as 30 Day PMs or Weekly Tasks. This creates unneeded redundancy, as the interval (30 in this case) is included in the PM record already. Additionally there is no task description here that refers to the actual work performed.

How do you create reusable tasks? Begin with the most generic tasks you can think of and create these first. Examples could be Inspect, Clean, Lubricate, etc. After these task descriptions have been created, go to the next step and create tasks that are somewhat more specific. Here are some examples: Check Wiring, Replace Lubricant, Lube Chains. Continue with increasingly more specific tasks always trying to avoid including the equipment or equipment component in the task description. Eventually, for specialized tasks that are only performed on specific equipment, it may become necessary to include a component of the equipment in the task description. Keep the task description short and focused on the actual task. Obviously if the task description is short, it may not fully describe the job. This is where detailed instructions and pictures are used.

Next, determine what interval units are needed for your PM system. Calendar-based PMs usually will use a day interval. For example every 7 days Lubricate Roller Chain(s). Other tasks may be demand based or based upon the actual runtime of the equipment. In some cases, hours or minutes may be appropriate. As you gain experience with this set of PM tasks and intervals changes to the tasks and intervals may be warranted. Consequently choose a system that makes editing existing PMs simple and without historical data loss.

Ensure that Adequate Resources are in Place

Listed below are resources you need for a successful preventive maintenance program:

  • Trained and available personnel.
  • Adequate spares, expendables, lubricants, drive chain, bearings, etc.
  • Time in the production or equipment runtime schedule to perform PMs.
  • A motivated team of maintenance professionals.

Personnel must be trained and capable of safely performing the required work. Vigorously enforce proper lockout/tagout procedures. Stock on hand for expendables and other spares used for PMs has to be adequate. Inadequate spares not only prevents completion of the PMs, but also hurts motivation when personnel attempting to perform their job are hindered by a lack of spares. As such, the purchasing department has to have an ordering system that stays ahead of preventive maintenance spares requirements. Additionally an accountability system (CMMS) helps track spares use for restocking purposes. In summary, show your maintenance technicians how important you believe preventive maintenance is by providing the materials and training needed for these important tasks.

Time is a resource. Time must be available so that personnel can perform their work. This may require scheduling changes so that maintenance personnel are available during scheduled equipment downtime. Given the right resources, your maintenance team cannot help but be motivated to succeed with equipment maintenance.

Use a Maintenance Software Solution to Track and Manage Maintenance

Now that the tasks, intervals, personnel, training and scheduling are established it is time to load the data into a preventive maintenance software system. With so many CMMS choices, it is important to do your research carefully. Approximately fifty CMMS companies go out of business annually and fifty more replace these. Choose a well-established long-term CMMS company that has a proven record of accomplishment. Ask the following questions when choosing a CMMS:

  • How long has the CMMS company been in business?
  • How flexible is the preventive maintenance system?
  • Are there different task list formats available?
  • Is it possible to automate task list issuance?
  • Do technicians have the ability to close their own PMs while maintaining the integrity of the data?
  • Is it possible to close PMs without leaving the plant floor?
  • How easy (or hard) is it to adjust preventive maintenance task schedules?
  • Are labor and parts costs easily summarized and reported?
  • Is there an objective way to know how to optimize task lists or task intervals based upon downtime or reliability data?

When evaluating a CMMS it is best to run a demonstration copy of the proposed system with your own sample equipment and tasks. Use the system for at least 30 days. Issue preventive maintenance task lists to your personnel. Get their buy-in by demonstrating the usefulness of the system. Prove to yourself and your maintenance technicians that using the software makes both of your jobs easier. Most importantly confirm that this system has the potential to improve equipment availability and reliability.

Consider support and training as part of the initial investment. CMMS software training is well worth the investment as it brings the maintenance department up to speed quickly with the CMMS and instills confidence in its use. This leads to better compliance in entering and updating data.

Price is important, however the real cost benefit of CMMS comes not from the initial investment in CMMS but in the ongoing use and benefits derived from that use. Some CMMS software solutions are subscription-based. Others are a one-time investment with a perpetual license. While there are several factors to consider in CMMS selection, initial investment (price) should be a low priority when the budget allows. Ask yourself this question: “Do you want to trust millions of dollars in equipment assets to a cheap CMMS?”

2. Implement Your New Preventive Maintenance Program

Now it is time to start reaping the benefits of your new preventive maintenance program. Here are a few questions to consider when implementing your new PM program:

  • Should tasks lists be printed, emailed or simply viewed through a tablet or smart-phone?
  • How are tasks closed and what data should be included?
  • Who should close the preventive maintenance tasks as they are completed?
  • What will you use the system when maintenance personnel are absent?
  • Should spare parts lists be included on the task list?
  • If spares are included on the task list, should stock levels automatically draw down when the PM is completed?

The answers to these question come down to company policy, industry requirements, regulations and personal preference.

3. Assess and Adjust Your Equipment Maintenance Program

Constantly assessing your preventive maintenance program is an integral part of managing this system effectively. Equipment runtime schedules change, equipment demand changes, personnel change, maintenance technologies and procedures change. Your primary assessment tool is equipment maintenance data. The longer you use your CMMS system the more data it accumulates. Assuming that you chose a CMMS that provides extensive analysis and reporting, this data is now a valuable decision-making store. Use this data for OEE (overall equipment effectiveness) and reliability analysis. Choose a CMMS that uses MTBF (mean time between failures) to suggest preventive maintenance task intervals. Using real runtime data to set PM task intervals eliminates guesswork.

Being a proactive maintenance manager you should be adjusting to these changes as needed. Here are some things to look out for and some ideas on how to react. Keep in mind that sometimes there is no substitute for an experienced maintenance manager’s intuition.

Equipment Runtime Schedule Changes

In some situations, preventive maintenance can only be performed while equipment is in a scheduled shut down period. This creates a problem for maintenance scheduling. Here are some ways to manage this situation.

  • Non-maintenance machine operators can complete some simple maintenance procedures such as minor lubrication tasks.
  • Double-team certain equipment when it is down.
  • Adjust maintenance schedules.
  • Use automated maintenance devices, such as lubricators.
  • Implement preventive maintenance procedures during unscheduled downtime.

Equipment Demand Changes

Equipment demand relates to more than just runtime schedule changes. Demand reflects the actual time equipment is running and how much work it performs during the scheduled period. Obviously triggering PMs based upon calendar days would not be appropriate in these cases. It is best to trigger PMs in this case based upon runtime hours, cycles, cuts or whatever the appropriate meter unit is for that equipment. Consequently this equipment should have a counting device or be connected to the system that automatically triggers preventive maintenance work orders through an OPC compliant data connection.

Select a CMMS software solution that reads OPC data directly from the equipment then automatically responds with a preventive maintenance work order at exactly the right moment.

Personnel Changes

The best way to overcome this inevitable change is to have detailed listings of preventive maintenance tasks, intervals, spares requirements and history. Make sure this information is available to pass on to the new person. The more organized your system is the easier is to move seamlessly through this change. Once again, a good preventive maintenance software solution addresses this need.

Additionally, ongoing training and cross training in various maintenance processes can offset personnel change issues.

Changes in Maintenance Technologies and Procedures

An example of this type of change could be a new sensor that provides critical maintenance data to an OPC server. This data in turn indicates the correct PM interval. Another example could simply be running the equipment only when needed. This action saves energy resources and may reduce wear and tear on the equipment.

Software is constantly improving. Desired options with preventive maintenance software solutions are as follows:

  • Is there a role-based permission capability that allows the maintenance technicians to close their own PMs?
  • Is there a mechanism to validate PMs closed by technicians?
  • Does the ability to temporarily assign tasks to an alternate maintenance technician exist?
  • Is it possible to gather runtime data through an OPC compliant data network and issue work orders automatically.

Summary

Preventive maintenance is the one of the primary responsibilities of the maintenance manager in a manufacturing environment. Many maintenance department activities are affected by, and rely on a successful preventive maintenance program. More importantly, success of the manufacturing facility as a whole is directly proportional to the quality of the design, implementation and management of the preventive maintenance system.

Protecting Storage Tanks From Lightning

Providing adequate and effective lightning protection for storage tanks constitutes a beneficial and cost-effective step in assuring both personnel safety and reliability. Fortunately, securing such protection is not difficult or complicated, and guidance is readily available. It helps to become familiar with some basic recommended practices and standards for reference. We will be referring to the National Fire Protection Association NFPA 780, Standard for the Installation of Lightning Protection Systems; the American Petroleum Institute API 545, Recommended Practice for Lightning Protection of Aboveground Storage Tanks for Flammable or Combustible Liquids; and the American Petroleum Institute API 2003, Recommended Practice for Protection Against Ignitions Arising Out of Static, Lightning, and Stray Currents.

Whenever considering lightning protection, it helps to fall back upon the three basic steps: bonding and grounding, surge suppression, and structural lightning protection.

BONDING AND GROUNDING. The first consideration is bonding and grounding. According to API 545, flat-bottom tanks are inherently self-grounding for lightning protection purposes. The mass of the tank and surface area of its bottom in contact with whatever material it occupies provides a sufficiently low-impedance path to conduct lightning currents without increasing the risk of ignition. This applies whether or not a non-conductive containment membrane is in place under the tank.

It should be noted that, although adequate for lightning grounding, the path to ground may be high resistance, rendering it unsuitable for AC power grounding. In the event of an AC power ground fault, the lack of a low-resistance return path may leave the tank energized. Therefore, we recommend at least one, and preferable one each 100′ of tank perimeter, “solid” connection to ground. This usually consists of a conductor attached to a grounding tab at the base of the tank shell running to a ground rod or to the grounding grid.

Bonding is simply a matter of electrically connecting different masses of inductance (metallic masses) together to maintain them at the same potential, to equalize changing potential, and to provide a path for lightning current between them.

The major area of concern is obviously the floating roof. On an external floating roof tank, there are three lightning events that can cause arcing between the roof and tank shell. The first is a direct strike to the roof itself or its appurtenances. In this case, all of the lightning energy must flow across the seals to the tank shell and to ground. The second is a direct strike to the top of the tank shell. In this case, the lightning energy flows down the shell to ground, and the roof potential must be equalized to that of the tank shell. In the third case, a nearby strike changes the potential of the tank shell, and much less difference in potential must be equalized between the roof and tank shell.

Lighting energy consists of two components with an intervening transition component. The first is a high-energy, short-duration surge of energy. The second is a lower-energy, longer-duration event. The first segment, although conveying high amperage, is so short that it does not normally cause ignition. Think of passing your finger quickly through the flame of a candle. However, the second segment consists of a few hundred amps (about equivalent to the electrical service into your home) over half to three-quarters of a second. When faced with resistance between the floating roof and tank shell, it can easily produce sufficient heat to cause the ignition of any flammable gasses present. Think of your kitchen stove on steroids.

Therefore, two types of conductors are required between the floating roof and tank shell. The first is a sliding contact between the roof and shell, and is intended to handle the short-duration, high-energy pulse. This has historically been addressed by the use of shunts between the roof and tank shell. These were developed to overcome the shortcomings on non-conductive seals. However, most modern tanks employ metallic shoes as the primary seal between the roof and shell. These shoes have many times the surface area of shunts. According to wording which will presumable be adopted in the next revision of both NFPA 780 and API 545, the presence of primary metallic shoe seals will negate the requirement for shunts.

Shunt Primary Metallic Shoe Seals

However, contacts sliding on contaminants produce arcing and sparking, raising the need for a second type of conductor, the bypass conductor. This is a hard electrical connection between the floating roof and tank shell. Because the bypass conductor must be of sufficient length to allow full range of motion of the tank roof, it requires time to become conductive. When it becomes conductive, it quenches any arcing at the sliding contacts, and conducts the long-duration, lower energy second segment of the lightning strike.

Bypass conductors

Another area of concern is thief hatches. The hatch itself rests on a rubber seal and is connected to its collar by a pin-type hinge. In the field, we have measured a high resistance between the thief hatch and its collar. Lightning current flow across that resistance is capable of producing sufficient heat and arcing to cause ignition. Therefore, a flexible jumper between the hatch and collar should be added to each.

SURGE SUPPRESSION. The second step in securing adequate protection is surge suppression. Any conductor running to or from a tank is perfectly capable of introducing all types of mischief. A surge suppressor is simply a device that keeps that from happening. Typical conductors found on a tank include AC power for site lights, pumps, valves, etc., and for data collection including levels, temperatures, flow rates, etc. Surge suppressors should be installed at the tank end of such conductors and also at their origin. This will limit the transient gremlins in their mischief.

STRUCTURAL LIGHTNING PROTECTION. The third step in securing protection is structural lightning protection. When we think of structural lightning protection we normally think of lightning rods on the roof of a building. It is important to remember that the purpose of a lightning rod system is to convey lightning energy around a non-conductive structure, such as a house or barn, thereby keeping that structure from burning down.

Note that there is absolutely no benefit to installing lightning rods on a tank. According to NFPA 780, the tank itself is inherently self-protecting. There are three components that make up a lightning rod system: the lightning rods, conductor system and grounding system. On a tank, the tank itself is of sufficient thickness to be substituted for the lightning rods, the shell is of adequate cross section to be substituted as the conductor system, and the site ground is more than adequate for lightning protection purposes. Therefore, the tank is self-protecting without the need to install additional components. Lightning rods would only tend to attract lightning to the tank.

There is, however, a technology alternative to conventional lightning rods. These are streamer-delaying air terminals. These air terminals, colloquially known as “fuzzy ball™” lightning rods, are designed to interrupt the lightning completion process by delaying the formation of lightning-completing streamers from objects on the surface of the earth.

A lightning strike begins with the formation of stepped leaders from the base of the storm cloud. These leaders jump in steps of around 150′, working their way downward towards the surface of the earth. When they reach to within 500′ or so of the surface, they begin pulling streamers of ground charge off of objects on the surface. Whichever streamer meets a stepped leader first determines what gets hit. As the ground charge builds on a streamer-delaying air terminal, the sharp points break down into corona under a low potential. When it comes time for a streamer to form from a protected object, the ground charge that would constitute the streamer has been partly dissipated into the atmosphere, thereby reducing the likelihood of a direct strike.

We use NFPA 780 as the design standard for protecting a tank. As the tank contains flammable material, we reduce the diameter of the rolling sphere to 100′, reducing the spacing between air terminals to jus over 12′. We install them around the perimeter of the tank shell on the foam injection plates and rim, and on the gauging platform. We also install them on the walkway handrail, if one is installed.

Streamer delaying air terminals on storage tanks

API 2003, Annex C, Direct Stroke Lightning Protection, C.1 notes that conventional lightning protection systems do not protect against indirect lightning currents or induced voltages. These are both major causes of ignition, particularly in production tanks. It further notes in C.2.1 that, according to vendor claims, streamer-delaying systems may have some benefit in protecting against indirect lightning currents of induced voltages. This type of performance is obviously preferable.

In the real world, we have seen a very high success rate with operators installing this type of system. Indeed, the cost has been justified many times over in both actual savings associated with extinguishing a fire and reducing lost time in service.

3 Keys to a Successful Preventive Maintenance Program

Preventive maintenance planning and practices influence most major maintenance department activities in a manufacturing environment. Here are some examples of this.

  • Equipment downtime is largely affected by preventive maintenance or the lack there of.
  • Repair work orders are subjected to the influences of the preventive maintenance program.
  • Purchasing and inventory are affected by preventive maintenance for routine replacement of expendable spares as well as repair parts required for unexpected downtime.

As evidenced by the points above, preventive maintenance should be “first base” for any maintenance department. Unfortunately sometimes routine preventive maintenance activities often do not get the attention or credit they are due. This is a mistake. So what are the keys to a successful preventive maintenance program?

1. Careful Planning of the Preventive Maintenance Program

Planning a preventive maintenance program involves the following:

  1. Determine tasks and intervals needed to maintain the equipment.
  2. Ensure that the appropriate resources are in place.
    • Schedule maintenance personnel for maximum preventive maintenance wrench time.
    • Understand how scheduled equipment downtime and maintenance personnel scheduling interface.
    • Manage spares effectively.
  3. Select a scheduling and accountability system (preventive maintenance software, CMMS software or equivalent)

Determine Maintenance Tasks and Intervals

A good preventive maintenance (PM) task list contains the following components:

  • The equipment item.
  • The task(s).
  • The person the task is assigned to.
  • A task interval.
  • A start date and due date.
  • Optional: Detailed instructions and pictures if needed.
  • Optional: Task completion sequence.

Begin with your equipment list. Next gather appropriate tasks for preventive maintenance task lists from OEM manuals or online manuals when possible. This is a good place to start, especially with newer equipment. In some cases, the equipment warranty is dependent upon following the OEM recommendations. Another source of tasks is the maintenance manager’s experience and intuition. Yet another source is branch locations running similar equipment.

When developing a task list, consider the reusability of the task descriptions. Reusability refers to using the same task description on potentially multiple equipment items. The benefit is that there are fewer tasks, no duplicate task descriptions and better reporting and analysis of PMs. Consider these examples:

REUSABLE task description: Lubricate Roller Chain(s)

NOT REUSABLE: Lubricate Roller Chain(s) on Conveyor #1

In the first example this task, Lubricate Roller Chain(s), is appropriate for any equipment with a roller chain. In the second example, Lubricate Roller Chain on Conveyor #1, is only appropriate on the Conveyor #1 PM task list. Imagine how cumbersome your preventive maintenance software management efforts become if you are not using reusable tasks. Another example that may cause problems later is naming conventions such as 30 Day PMs or Weekly Tasks. This creates unneeded redundancy, as the interval (30 in this case) is included in the PM record already. Additionally there is no task description here that refers to the actual work performed.

How do you create reusable tasks? Begin with the most generic tasks you can think of and create these first. Examples could be Inspect, Clean, Lubricate, etc. After these task descriptions have been created, go to the next step and create tasks that are somewhat more specific. Here are some examples: Check Wiring, Replace Lubricant, Lube Chains. Continue with increasingly more specific tasks always trying to avoid including the equipment or equipment component in the task description. Eventually, for specialized tasks that are only performed on specific equipment, it may become necessary to include a component of the equipment in the task description. Keep the task description short and focused on the actual task. Obviously if the task description is short, it may not fully describe the job. This is where detailed instructions and pictures are used.

Next, determine what interval units are needed for your PM system. Calendar-based PMs usually will use a day interval. For example every 7 days Lubricate Roller Chain(s). Other tasks may be demand based or based upon the actual runtime of the equipment. In some cases, hours or minutes may be appropriate. As you gain experience with this set of PM tasks and intervals changes to the tasks and intervals may be warranted. Consequently choose a system that makes editing existing PMs simple and without historical data loss.

Ensure that Adequate Resources are in Place

Listed below are resources you need for a successful preventive maintenance program:

  • Trained and available personnel.
  • Adequate spares, expendables, lubricants, drive chain, bearings, etc.
  • Time in the production or equipment runtime schedule to perform PMs.
  • A motivated team of maintenance professionals.

Personnel must be trained and capable of safely performing the required work. Vigorously enforce proper lockout/tagout procedures. Stock on hand for expendables and other spares used for PMs has to be adequate. Inadequate spares not only prevents completion of the PMs, but also hurts motivation when personnel attempting to perform their job are hindered by a lack of spares. As such, the purchasing department has to have an ordering system that stays ahead of preventive maintenance spares requirements. Additionally an accountability system (CMMS) helps track spares use for restocking purposes. In summary, show your maintenance technicians how important you believe preventive maintenance is by providing the materials and training needed for these important tasks.

Time is a resource. Time must be available so that personnel can perform their work. This may require scheduling changes so that maintenance personnel are available during scheduled equipment downtime. Given the right resources, your maintenance team cannot help but be motivated to succeed with equipment maintenance.

Use a Maintenance Software Solution to Track and Manage Maintenance

Now that the tasks, intervals, personnel, training and scheduling are established it is time to load the data into a preventive maintenance software system. With so many CMMS choices, it is important to do your research carefully. Approximately fifty CMMS companies go out of business annually and fifty more replace these. Choose a well-established long-term CMMS company that has a proven record of accomplishment. Ask the following questions when choosing a CMMS:

  • How long has the CMMS company been in business?
  • How flexible is the preventive maintenance system?
  • Are there different task list formats available?
  • Is it possible to automate task list issuance?
  • Do technicians have the ability to close their own PMs while maintaining the integrity of the data?
  • Is it possible to close PMs without leaving the plant floor?
  • How easy (or hard) is it to adjust preventive maintenance task schedules?
  • Are labor and parts costs easily summarized and reported?
  • Is there an objective way to know how to optimize task lists or task intervals based upon downtime or reliability data?

When evaluating a CMMS it is best to run a demonstration copy of the proposed system with your own sample equipment and tasks. Use the system for at least 30 days. Issue preventive maintenance task lists to your personnel. Get their buy-in by demonstrating the usefulness of the system. Prove to yourself and your maintenance technicians that using the software makes both of your jobs easier. Most importantly confirm that this system has the potential to improve equipment availability and reliability.

Consider support and training as part of the initial investment. CMMS software training is well worth the investment as it brings the maintenance department up to speed quickly with the CMMS and instills confidence in its use. This leads to better compliance in entering and updating data.

Price is important, however the real cost benefit of CMMS comes not from the initial investment in CMMS but in the ongoing use and benefits derived from that use. Some CMMS software solutions are subscription-based. Others are a one-time investment with a perpetual license. While there are several factors to consider in CMMS selection, initial investment (price) should be a low priority when the budget allows. Ask yourself this question: “Do you want to trust millions of dollars in equipment assets to a cheap CMMS?”

2. Implement Your New Preventive Maintenance Program

Now it is time to start reaping the benefits of your new preventive maintenance program. Here are a few questions to consider when implementing your new PM program:

  • Should tasks lists be printed, emailed or simply viewed through a tablet or smart-phone?
  • How are tasks closed and what data should be included?
  • Who should close the preventive maintenance tasks as they are completed?
  • What will you use the system when maintenance personnel are absent?
  • Should spare parts lists be included on the task list?
  • If spares are included on the task list, should stock levels automatically draw down when the PM is completed?

The answers to these question come down to company policy, industry requirements, regulations and personal preference.

3. Assess and Adjust Your Equipment Maintenance Program

Constantly assessing your preventive maintenance program is an integral part of managing this system effectively. Equipment runtime schedules change, equipment demand changes, personnel change, maintenance technologies and procedures change. Your primary assessment tool is equipment maintenance data. The longer you use your CMMS system the more data it accumulates. Assuming that you chose a CMMS that provides extensive analysis and reporting, this data is now a valuable decision-making store. Use this data for OEE (overall equipment effectiveness) and reliability analysis. Choose a CMMS that uses MTBF (mean time between failures) to suggest preventive maintenance task intervals. Using real runtime data to set PM task intervals eliminates guesswork.

Being a proactive maintenance manager you should be adjusting to these changes as needed. Here are some things to look out for and some ideas on how to react. Keep in mind that sometimes there is no substitute for an experienced maintenance manager’s intuition.

Equipment Runtime Schedule Changes

In some situations, preventive maintenance can only be performed while equipment is in a scheduled shut down period. This creates a problem for maintenance scheduling. Here are some ways to manage this situation.

  • Non-maintenance machine operators can complete some simple maintenance procedures such as minor lubrication tasks.
  • Double-team certain equipment when it is down.
  • Adjust maintenance schedules.
  • Use automated maintenance devices, such as lubricators.
  • Implement preventive maintenance procedures during unscheduled downtime.

Equipment Demand Changes

Equipment demand relates to more than just runtime schedule changes. Demand reflects the actual time equipment is running and how much work it performs during the scheduled period. Obviously triggering PMs based upon calendar days would not be appropriate in these cases. It is best to trigger PMs in this case based upon runtime hours, cycles, cuts or whatever the appropriate meter unit is for that equipment. Consequently this equipment should have a counting device or be connected to the system that automatically triggers preventive maintenance work orders through an OPC compliant data connection.

Select a CMMS software solution that reads OPC data directly from the equipment then automatically responds with a preventive maintenance work order at exactly the right moment.

Personnel Changes

The best way to overcome this inevitable change is to have detailed listings of preventive maintenance tasks, intervals, spares requirements and history. Make sure this information is available to pass on to the new person. The more organized your system is the easier is to move seamlessly through this change. Once again, a good preventive maintenance software solution addresses this need.

Additionally, ongoing training and cross training in various maintenance processes can offset personnel change issues.

Changes in Maintenance Technologies and Procedures

An example of this type of change could be a new sensor that provides critical maintenance data to an OPC server. This data in turn indicates the correct PM interval. Another example could simply be running the equipment only when needed. This action saves energy resources and may reduce wear and tear on the equipment.

Software is constantly improving. Desired options with preventive maintenance software solutions are as follows:

  • Is there a role-based permission capability that allows the maintenance technicians to close their own PMs?
  • Is there a mechanism to validate PMs closed by technicians?
  • Does the ability to temporarily assign tasks to an alternate maintenance technician exist?
  • Is it possible to gather runtime data through an OPC compliant data network and issue work orders automatically.

Summary

Preventive maintenance is the one of the primary responsibilities of the maintenance manager in a manufacturing environment. Many maintenance department activities are affected by, and rely on a successful preventive maintenance program. More importantly, success of the manufacturing facility as a whole is directly proportional to the quality of the design, implementation and management of the preventive maintenance system.

Three Huge Reasons Humidity Control Is So Important in Industrial Environments

When it comes to industrial environments, there’s no doubt within the industry that maintaining effective control of humidity is essential. It’s a key part of the operation of countless factories across the globe and can make the difference between success and failure in many areas of industrial production.

But why is that the case? After all, humidity has been a constant for as long as there’s been air and plenty of things have been produced in that time, right?

That may be true, but it doesn’t tell the whole story – a story of increasingly complex manufacturing and industrial processes that benefit greatly from tight humidity control. Here’s three huge reasons why industrial environments now live or die by their humidity control.

Staff health and wellbeing

You only need to spend a day outside on a humid day to know that high levels of RH (relative humidity) can have a debilitating effect on your ability to function properly. However, it’s low RH which industrial businesses are keen to avoid.

Low RH can lead to dry and itchy eyes and cause the respiratory system to dry out, leading to dehydration in staff. Additionally, it causes a dramatically increased spread rate of pathogens like the influenza virus, which survives best in low RH environments.

On top of these issues, low RH has been linked to conditions like Sick Building Syndrome and the intensity of chemical pollution, caused by gases from materials used inside industrial buildings.

Taken together, these issues lead to a poor working environment for staff, and can even violate health and safety guidelines within certain nations.

Building maintenance

When water in the air interacts with cold surfaces, it creates condensation. Within industrial premises, which typically feature large amounts of exposed metalwork and very little by way of traditional insulation, this water can have a devastating effect on the health of your building.

By allowing condensation to develop, you encourage the build-up of both rust and mildew on surfaces which can in turn affect both the structural integrity and air quality of your building.

Product output

Industrial manufacturing businesses survive by what they output. Whether that’s car parts of pre-fab buildings, what a business outputs determines its success.

Humidity plays a crucial role in ensuring that products are manufactured to the highest possible standards by eliminating the role that high RH plays in spoilage. Consider, for a moment, that cardboard remains by far the most common material for packaging products of all kinds.