So, What’s the Deal With Seals?

Does your familiarity with valves start and end with a dictionary definition? If you’re reading this article, probably not. But just in case, here’s Merriam-‐Webster’s take on valves:

[Valves are] any of numerous mechanical devices by which the flow of liquid, gas, or loose material in bulk may be started, stopped, or regulated by a movable part that opens, shuts, or partially obstructs one or more ports or passageways.

Frankly, that’s not a bad start. Valves are, in fact, numerous, mechanical and devices. And they do start, stop and regulate flows of liquids, gases and loose materials (e.g., slurries). And yes, movable parts do open, shut or partially obstruct passageways (i.e., piping and tubing).

The truth is, many valves and fittings are highly engineered devices machined to extremely close tolerances—like those CPV manufactures. And integral to any valve’s ability to serve its intended application is its sealing performance. In fact, engineering and specifying the sealing for any valve or fitting’s application is just as important as its overall design itself.

Valves are technically fittings. Though they perform different functions within a system, they do complement each other. And while it’s worth considering them separate categories when purchasing for your application, when it comes to sealing properties, they’re not all that different.

Why Sealing Matters

Whether for a valve or fitting, seals serve one purpose: reduce leaks, whether fluid or gaseous. It’s estimated that roughly 300,000 tons of fugitive emissions (the unintended discharge of gases or vapors) are released annually in the US alone. Inadequate sealing is the root cause, and better sealing is the only solution.

Beyond curtailing fugitive emissions, better sealing technology—like the CPV-‐developed line of O-‐SEAL valves and fittings—has other practical benefits. Most notably, high-‐quality seals extend the service life of the equipment used within an application. In other words, a good seal saves money, time, the environment and, potentially, prevents catastrophic failure.

While beyond the scope of this article, the predominant regulatory standards by which valves are tested and certified to ensure fugitive emission tightness are ISO 15848 in most of Europe, VDI 2440 in Germany and API 622 and 624 in the United States. CPV products meet or exceed the qualifications for all these standards.

Sealing Materials in Use Today

The materials used for mechanically sealing rotary elements of valves (e.g., valve stems) are numerous. Stainless steel, titanium, bronze, aluminum, chromium, various carbons, tungsten, silicon…the list goes on and on. But just as important, if not more so, are the flexible parts of these components.

Flexible parts are often made from synthetic elastomers, which are polymers with elastic properties. Some typical examples in use today are nitrile, chloroprene, ethylene propylene and butyl rubber. And then there’s graphite, which is a ubiquitous packing material, and polytetrafluoroethylene (PTFE, or Teflon, made famous by your nonstick cookware). Again, the list goes on and on, and even includes natural vegetable fibers like jute and cotton, along with human-‐made fibers like acrylic and melamine.

Better Seals for Challenging Conditions

When it comes to properly sealing valves and fittings, some industrial applications pose more challenge than others. Industrial gas, petrochemical and shipbuilding, for instance. All rely on high-pressure systems, and all happen to be the primary industries for which CPV manufactures.

CPV is perhaps most well-‐known for our O-‐SEAL line of valves and fittings, designed to meet the stringent requirements of the US Naval force. In fact, CPV outfits every US Navy surface vessel and submarine in operation today. The O-‐SEAL line has seen success outside of shipbuilding, though. Gas refineries, for example, rely on its leak-‐proof performance, safety and reliability.

Specific to the smaller valves found in the processing sections of refineries, the O-‐SEAL limits the release of fugitive emissions to incredibly low levels, as has been verified by independent laboratory testing. The design has a flexible O-‐ring made from ethylene propylene, polyurethane, Chemours Viton™ or, in certain cases, a custom solution. The O-‐ring is recessed within a close-‐tolerance groove on either side of the valve’s flat-‐faced union ends, offering slip-‐in, slip-‐out convenience. The bubble-‐ tight seal this creates withstands heavy vibration and pressure surge far better than gasket or metal-‐to-‐metal types seals.

Depending on the seal material selected, these valves will function from −65°F (−54°C) to 400°F (204°C). They also handle the most elusive gases such as helium and hydrogen.

The entire O-‐SEAL line of shut off, needle, check and relief valves are rated for vacuum to 6,000 psi (413 BAR) in liquid or gas service. But they’ve been tested to much higher pressures without failure. CPV’s Mark VIII O-‐SEAL fittings, for example, when heat sealed into a system by welding, orbital welding or brazing, can sustain in excess of 16,000 psi. Just take a look at the picture to the left and the chart below. In this test, Mark VIII O-‐SEAL fittings were brazed—the most basic heat-‐sealing technique, requiring only a handheld propane torch—to brass, copper, steel and stainless steel tubing. In every test, the tubing failed while the Mark VIII fittings remained intact. And in every test, the burst pressures far exceeded the fitting 6,000 psi pressure rating. You’ll notice the test using 1/16” stainless steel tubing with a steel Mark VIII threadpiece had to be terminated at a whopping 28,000 psi!

Now, while we absolutely discourage our clients from taking CPV’s valves and fittings beyond their official maximum pressure ratings, this is an undeniably impressive performance.

Sealing Up

Without adequate sealing, even the best-‐engineered, machined-‐to-‐the-‐finest-‐tolerances valves are useless to the industries that rely on them. For more than 100 years, CPV has been at the forefront of all of the above. And we have the numbers to back that up.

The Advantages of Replacing a Soft Goods Kit

The Advantages of Replacing a Soft Goods Kit A failing valve is not just troublesome, it is a potential weak link in an otherwise robust chain. Some of the smallest parts within an already compact valve are those most crucial to a system’s overall performance—they have the power to ensure smooth operation or result in catastrophic failure. It is essential, then, to maintain the performance of your valves by replacing soft goods both when necessary and proactively. And you should always follow the practice of installing soft goods kits that are designed and manufactured according to the specifications set forth for the exact valve you are servicing. Read on to learn more about the advantages of using soft goods kits.

Why Replace Soft Goods?

Soft goods need to be replaced for two primary reasons. The first and most urgent is when a valve’s sealant is leaking. Visible leakage is a clear indicator that the valve cannot function properly, and threatens the entire application’s reliability and the safety of the equipment operator.

The second reason soft goods are replaced is simply because it is smart to change them at set intervals, even if there is no noticeable damage. Employing such preventive measures ensures continued, healthy and reliable valve operation.

Soft Goods Kits and Their Benefits

Soft goods kits are the most cost-effective solution for repairing faulty valves. Rather than having to purchase a new valve assembly, it is significantly more economical to buy a kit designed to repair your otherwise serviceable valve. In many situations, the stem seal, O-Rings and packing are typically the only portion of the valve that needs to be replaced. In this case, by isolating and repairing the root problem, you now have a well-functioning system that did not necessitate the replacement of the entire structure. This stretches the lifespan of an already long-lasting valve and is more practical than starting from scratch with a new product.

Ensuring your valves operate at peak performance saves time and expense by eliminating or reducing the likelihood of unplanned repairs. Key team members are now freed to focus on other aspects of process outcomes, resulting in increased efficiency and further cost reductions. Soft goods kits are valuable because of their assurance of reliability, their ease of use in fixing an isolated problem and their time-saving convenience.

Where to Select a Soft Goods Kit

Soft goods kits include all necessary components to replace a leaking—or functioning, but older—valve part. Kits typically contain many possible replacement parts, as well as the tools needed to remove the original part. Exactly which replacement parts and which tools will depend on the original valve design’s specifications.

Individual manufacturers sell their own soft goods replacement kits. The specifications of soft goods are set by the original designers of the valve depending on the application for which they will be used. Factors like temperature and exposure to other environmental conditions, in addition to the chemicals and compounds they will be in contact with, influence every decision behind the engineering of soft goods.

For this reason, it is essential to choose a kit supplied by the valve’s original manufacturer. This ensures the same reference number, and reduces the risk of replacing parts with different filling percentages, which are, essentially, the recipes that determine the makeup that fulfills the application requirements of the soft good. It also guarantees that the new parts will not be counterfeit, and are exactly suited to your valve’s application.

Consequences of Using the Wrong Soft Goods Kit

While a faulty valve may seem to perform well with a nonspecific replacement part, it will not function to its fullest potential because it is not precision-matched to the original engineering specifications. In larger and more critical applications, it is especially important to certify that each individual part works correctly, and this can only be accomplished by using materials sourced from the original manufacturer.

It can’t be overstated: replacing soft goods with cheap or illegitimate alternatives is a danger not just to the result of the application, but to the workers controlling and being exposed to these products. The consequences of a valve error extend well beyond the valve itself. Every product and every person working with and relying on that valve will be at risk. This is especially true in high-pressure environments. To prevent failure, it is essential to replace soft goods as soon as trouble presents itself or, better yet, according to a preventive maintenance schedule.

Selecting the Right Soft Goods Kit with CPV

CPV offers soft goods kits for our durable O-SEAL and G-Series product lines. Valves from each line provide long-lasting performance, and should be checked for maintenance at regular intervals, especially if they are used frequently or in extreme conditions. The following sections will review soft goods kit selection and installation for our O-SEAL products.

An O-SEAL valve’s O-ring is recessed within a close-tolerance groove on each of the flat-faced union ends for slip-in, slip-out convenience. This creates a bubble-tight seal that can withstand heavy vibration or pressure surges far better than a gasket.

The soft goods in the cartridge are removable and are specified in different materials for different applications. The software makeup is determined by its compatibility with the liquid or gas it will come in contact with and the temperature range of the application. Because the cartridge is easily removed from the valve for maintenance or replacement, the cost of purchasing a new valve can be avoided. In most cases, the cartridge can be served off-line with a new soft goods kit for re-use another time.

While most stem seals are made of rubber, O-SEAL stem seals are fabricated from polyurethane, Viton and ethylene propylene. Please see the chart below to determine the proper material grouping shown across the top of the chart. Read down the column and select the Kit Number from the row matching the valve size or Dash Number.

For example:

A ½” 380-3 Globe valve requires a soft goods kit. The valve is used in compressor air service, and the compressor is lubricated with a petroleum-based oil. The materials listed in the first column under Material Grouping are satisfactory for this service. Continue down this column to the line for Dash No. -3 (½” pipe size) to determine that the Kit Number is 003803.

The Advantages of Replacing a Soft Goods Kit

How to Use Our Soft Goods Kit

If a seal needs to be replaced, meet our leakproof standards by using the “U” cup installation tool developed exclusively for CPV applications. An inexpensive choice, the “U” cup is a simple solution that replaces stem seals in less than a minute. By compressing the outer sealing lip and expanding the inner lip, the kit makes it easy to slip the “U” cup stem seal over the valve stem. Once the stem seal is properly installed on the valve stem, it can be easily inserted into the bonnet gland and secured without damaging the critical edges of the seal.

For step-by-step instructions on how to install “U” cup steam seals in CPV O-SEAL system valves, see the image below:

In Conclusion

Soft goods kits are an inexpensive method for repairing, rather than replacing, a faulty valve. Because every valve has specific material requirements, it is best to choose a soft goods kit from the original manufacturer, ensuring the exacting specifications and application suitability. Again, this is especially true for the most critical applications. And while soft goods kits can be used when a valve is noticeably leaking, it is wise to change out soft goods according to a predetermined preventive maintenance schedule to ensure prime valve functionality and worker safety.

CPV offers soft goods kits for both our O-SEAL and G-Series valves. For more information about CPV soft goods, or any other general queries, please visit cpvmfg.com or contact sales@cpvmfg.com.

Valve Maintenance and Tools

Valve maintenance is necessary to keep your valves running smoothly at all times. Valves are important to your process, and the results could be disastrous if they stop functioning the way they were designed to. Your valves require maintenance to work their best.

CPV Manufacturing has been the leader of valves and fittings since 1915. Safety is our first priority, so we’re dedicated to providing products that will help you avoid disaster.

Learn more about how to maintain your valves to ensure that they’re functioning properly and the tools that allow them to keep working.

O-Seal Valve Installation, Operation, and Disassembly Instructions: These will explain how to install fittings or valve end connections, from installation to operation to inspection and disassembly. There are also specific instructions on correcting leakage for tight seating and for assembly.

Valve Lubrication: This section explains the benefits of regularly lubricating valves in a system, even if the valve only performs an opening and closing action. It’s important to lubricate two surfaces that continuously slide over one another. It makes the parts last longer and work better.

While hydraulic piping systems can function without additional valve lubrication, gas piping systems function under high pressures and benefit from lubrication.

After you order your valves, CPV will detail the regular lubrication schedule and help you set it up.

Valve Flush Plugs: This section explains the function of valve flush plugs, why they’re beneficial, and how to use them.

Valve flush plugs protect the rest of the system from contamination if one section of a piping system needs to be altered, cleaned, or flushed. The three types of flush plugs are Under-Seat, Over-Seat, and Flow-Thru.

Under-Seat and Over-Seat allow for a trouble-free connection to the flushing pump. Flow-Thru plugs are meant to be inserted in valves that are in the middle of the section and being flushed or cleaned.

Valve Spacers: O-SEAL valves are exposed to the heat of welding or brazing during installation that can compromise their cleanliness and integrity. Valve spacers will help to reduce this risk.

You can also use the spacer over and over again to continue to flush the system if you encounter future problems or contamination.

The O-SEAL Valve: The Big Difference Small Valves Can Have in the Gas Filling Process

In the gas industry, products must perform correctly in order to operate safely and effectively as well as to reduce risks. CPV Manufacturing’s products are designs that have become crucial to this industry in the daily function of packaged gas operations and fill plants. These products help with the plants’ productivity and accuracy.

CPV’s O-SEAL fittings have been installed in numerous gas-filling facilities around the world and have become a standard with many gas manufacturers worldwide. CPV’s valves and fittings are known for their leak-proof performance, safety, and operative reliability.

The O-SEAL is specific to small valves found in processing sections of refineries. The seal controls the amount of greenhouse gas emitted. When the stem opens and closes the valve, there are fugitive emissions standards for a very fine amount of gas that can leak through the stem. Because of the opening and closing, a microscopic amount of gas leaks through the seal, but the fugitive emissions sets a stringent limit.

Our O-SEAL valves and fittings for the industrial gas industry are qualified under Fugitive Emissions standard ISO 15848 and leads the industry in having small valves, meaning valves under 2 inches, that qualify to the stringent standard of Fugitive Emissions.

O-Seal valves and fittings are independently tested by laboratories that tested the standard and are unique to CPV in the way that they’re are up to 3 inches, but they go up to 48 inches. The standard is very stringent.

O-Seal hand valves are flat faced and soft seated and are differentiated from other valves because of their reputation for leak-proof reliability and long service life. In addition, O-SEAL hand valves provide low torque and a hand tighten positive bubble tight seal.

The O-SEAL line includes shut off, needle, check, and relief valves that are rated for vacuum to 6,000 psi (413 BAR) in liquid or gas service. These valves will function from -65°F (-54°C) to 400°F (204°C). The O-SEAL valve line handles the most elusive gases, such as helium and hydrogen, and accommodates pipe and tube size ranging from 1/8 to 2 inches.

CPV’s unique O-SEAL System design has a flexible O-ring that’s recessed into a close tolerance groove on each of the flat-faced union ends for slip-in/slip-out convenience. This creates a bubble tight seal that can withstand heavy vibrations or pressure surges far better than gasket or metal-to-metal type seals.

O-SEAL System valves also provide users with a cost-of-maintenance advantage in an interchangeable valve cartridge. The soft goods within the cartridge are removable and can be specified in different materials for special applications. The software group is determined by compatibility with the liquid or gas and the temperature range of the application. The cartridge can be easily removed from the valve to be fixed or replaced, so you’ll avoid the cost of purchasing a new valve.

So, What&#8217;s the Deal With Seals?