Blaming the Valve

March 4, 2019

By: Bruce Ellis

In many situations where a system starts to suddenly fail, the valve is the first suspect. This may or may not be true, depending on the issue. If a swing check valve is being used it is important to remember they are inherently noisy, so a quiet swing check is a problem. Whereas a non-slam check valve is designed to operate quietly, so if it becomes noisy, there is a problem.

Here are 3 questions to ask to help diagnose the issue causing system failure:

  1. Did the systems components change?

Simply put, is your pump or compressor working at the same efficiency (flow rate and pressure) as when it was new? Or did something change? It’s a good idea to have a pressure gauge and flow meter installed to monitor the conditions.

  1. Did something foreign enter the system?

Foreign objects sometimes find their way into a system causing damaged components, such as impellers and pistons. These objects can possibly get jammed in a valve, causing it to become stuck in the “open” or “closed” position. This can occur when intake screens become dislodged after repairs have been done, or on new installations. There have been documented occurrences where rocks, pieces of wood and even hand tools have been stuck in valves.

  1. Has there been a change in process conditions?

The media in a process can change. Is it more acidic? Does it contain more particulate? Did the specific gravity change? Any or all of the these will change how a valve operates. Increased acidity can cause failure of the spring and corrosion of the wetted parts. Increased particulate will cause faster wear of all parts and can lead to leaks and failure of a valve and other components in the system. A thicker than normal media will put strain on a pump and can slow the “close time” of a valve.

To help save money and down time, it is highly important to have an inspection and maintenance schedule to keep your system working properly and safely.

It’s all about efficiency!

Download the DFT® Silent Check Valve 6-page Brochure now!

Material Spotlight – PTFE (Polytetrafluoroethylene)

Feb 14, 2019

By: Michael Pawlowski

From interplanetary deep space missions to sealing the fittings between the faucets and pipes in your kitchen sink, Polytetrafluoroethylene (PTFE) can be found being used in almost every aspect of our daily lives. It was discovered accidentally April 6, 1938 by Dr. Roy J. Plunkett while running experiments utilizing gasses for freon refrigeration. The white waxy substance that had spontaneously polymerised was found to have some remarkable properties. PTFE turned out to be a resin impervious to almost every known solvent with a near frictionless surface which no substance would stick to.

The unique properties of PTFE lend itself well for use in a variety of industrial, manufacturing, and engineering facilities. The superb chemical resistance and tolerance to vast temperature gradients has not only improved the efficiency of many industries but the safety for the employees that work around those conditions as well.

12 ADVANTAGES OF USING PTFE FILLED COMPOUNDS

  • Excellent chemical resistance
  • Wide range of service temperature
  • Excellent dielectric properties
  • Non-stick, low friction
  • No embrittlement or ageing
  • Smooth surface finish can be achieved
  • Non wetting
  • Outstanding corrosion protection
  • Electrical insulation
  • High thermal stability and flame resistance
  • Resistance to weathering
  • Food grade compliancy

5 COMMON GRADES OF PTFE

Virgin PTFE
“Virgin PTFE” (PTFE without a filler) is one of the most chemically inert materials known and is used in many different applications and industries.

Glass Filled PTFE
Virgin PTFE with 25% Glass fiber filler which dramatically increases compressive strength and lowers deformation under load.

Bronze Filled PTFE
The addition of Bronze to PTFE gives better dimensional stability and lowers creep, cold flow and wear.

Carbon Filled PTFE
The addition of Carbon Fibre to PTFE increases the compressive strength and wear resistance. It provides good thermal conductivity and low permeability.

Stainless Steel Filled PTFE
The material is extremely hard wearing, has excellent strength and stability under extreme loads and elevated temperatures whilst still retaining the low coefficient of friction of conventional PTFE.

PROCESSING PTFE

Because PTFE is a thermoplastic and due to its high viscosity, it cannot be processed using conventional polymer processing techniques. PTFE is processed by cold shaping and followed by heat treatment (sintering) during which polymer particles fuse to form a solid moulding.

PTFE is highly resistant to corrosion due to its chemical inertness. Unfortunately, that same chemical inertness prevents PTFE from being cross-linked like elastomers and is subject to the phenomenon of cold-flow – otherwise known as “creep”. To reduce and diminish cold-flow, additives are introduced during the preparation of PTFE compounds. Fillers, such as glass fiber found in Durlon® 9000 and 9000N gaskets, not only reduce creep but also maintain chemical inertness against aggressive and caustic chemicals but are still considered safe for use by food, drug and medical services.

Durlon® 9000 & 9000N PTFE SHEETS & GASKETS

Various shapes of inorganic fillers have been homogeneously blended with pure PTFE resins to give Durlon® 9000 its physical and mechanical properties. It is suitable for use in steel flanges and will not exhibit the cold flow problems associated with virgin PTFE or the hardness problems of some other filled PTFE products. It cuts easily and separates cleanly from flanges after use.

Certifications
Durlon® 9000 – API Standard 6FA Fire Test, TA-Luft (VDI 2440), BAM, Pamphlet 95 (Chlorine Institute), FDA Compiant, USP Class VI Certified, ABS-PDA Certified, EC 1935/2004 Compliant, DNV-GL Accreditation, RoHS Reach Declaration

Durlon® 9000NFDA compliant, ABS-PDA Certified, USP Class VI Certified, RoHS Reach Declaration

 

Durlon® 9000 is made with Teflon™ fluoroplastic. Teflon™ is a trademark of The Chemours Company FC, LLC used under license by Triangle Fluid Controls Ltd.

It’s not me…it’s you!

Jan 31, 2019

By: Chett Norton, C.E.T.

I have had many conversations over the years with end users and installers, and the majority of the time, we realize that it wasn’t the gaskets fault for blowing. I often chuckle to myself wondering how the conversation would go if a gasket could talk to its end user? I think it would be very similar to the stereotypical relationship break-up line, “It’s me…it’s not you” but just the opposite, “It’s not me…it’s you” ‑ gasket talking to the end user.

Gasket failures are far too common and in a lot of cases can be categorized into 4 main categories – as this poll explains that was conducted by the FSA on 100 gasket failures. They determined the root cause of the failure causes as:

  • Under Compression (68%)
  • Over Compression (14%)
  • Wrong Product Used (14%)
  • Other (4%)

Under Compression can be caused by not tightening the bolt enough to apply the correct load on the gasket due to manual tightening or friction that is unaccounted for or possibly due to gasket relaxation. As you begin to tighten the material it will start to “creep” due to the compressive load being applied. As the gasket thickness decreases, the originally applied load on the bolts will lessen. This is due to the thickness change resulting in a lower gasket stress or compression and can cause a leak due to permeation through the gasket or tangential between the gasket and the flange sealing surface. Additionally, unloading of the gasket can occur due to temperature or pressure cycling which can have the same effect.

Over Compression is caused by too much load on the gasket. This can be caused by not using the correct torque value or perhaps using a tightening tool that you cannot measure the torque, for example an impact gun or cheater bar extension. Over compression reduces the contact area of the gasket and crushes the gasket towards the ID allowing fluid to penetrate the gasket ID thus leading to deterioration of the gasket, damaged flanges and can result in leakage or gasket failure ‑ a huge problem.

When Wrong Product is used, it can become a serious safety issue. The material selected must be capable for the temperature, pressure and media that it is being installed into. If the gasket material is not rated for either the pressure or temperature of the application, this can cause very serious issues such as worker injury or plant down time. Additionally, the gasket must be chemically compatible with the media or the chemical can attack the gasket; causing it to prematurely break down which may cause leakage or even failure.

And lastly, the Other category could be several things, such as using the incorrect gasket size, poor method of cutting, or quite simply, it is somewhat of anomaly and couldn’t be grouped into one of the three categories above.

The good news is, 96% of the above listed failures can be eliminated as they are in YOUR control! By following these few points, you can ensure that your gasket doesn’t have to give you “The Talk”.

  • Pick the correct material, verify the pressure, temperature and media that you will be installing the gasket into.
  • Use the proper tightening procedure noted in ASME PCCC-1.
  • Lubrication is key, friction is robbing and can account from more than 50% of the required torque.
  • Always use the manufacturers recommended torque values. If you are unsure, give them a call as they will be happy you did.
  • Use a proper tightening tool, such as torque wrench.
  • Gasket creep and bolt relaxation happens, be sure to eliminate this by always remembering to re-torque within 4-24 hrs.

So, the next time you have a gasket related issue, check to make sure it wasn’t due to one of the reasons mentioned above and remember to think to yourself WWTGGDWhat Would The Gasket Guru Do?

Until next time, keep the fluid between the pipes!

At Triangle Fluid Controls Ltd., we provide Gasket Installation Training to help prevent lost production time, to decrease maintenance costs, eliminate fines and to help ease your health and safety concerns.

2017 Randy McKay Sales Award goes to…..

Triangle Fluid Controls (TFC) is pleased to award the 2017 Randy McKay Sales Award of Merit to Ryan Kelly in recognition for his outstanding sales performance with TFC. The award is given to TFC’s Regional Sales Manager (RSM) whose territory had the largest year-over-year sales increase from 2016 – 2017 and was presented August 23rd, 2018 at TFC’s headquarters in Belleville, Ontario. “I am extremely proud to present this award to Ryan Kelly for the second time in 3 years.” said TFC’s General Manager, Mike Boyd. “Ryan joined TFC in 2015 and has demonstrated a high level of energy and commitment to drive sales growth in Ontario and Manitoba. Given Ryan’s passion for his work, I am very excited to see what the future holds for Ryan and his sales territory”.

The award, created in memory of the late Randy McKay, TFC’s Central Canada RSM, was created by TFC President Mike Shorts, as a means of paying homage to the former TFC employee. “Randy did a lot for TFC, was a stand-up individual, and somebody that I personally, learned a lot about sales from. After Randy’s passing in 2015, I knew I wanted to create an award in his memory.”

The award includes two pieces: an engraved glass plaque and hand-blown glass sculpture made in a similar shape, style, and colouring to TFC’s company logo. The glass plaque will hang in TFC’s lobby with each year’s winner added to it. The making of the pieces, commissioned by a local glass blower in Wellington, Prince Edward County, and was completely documented and can be found posted online on TFC’s social media channels or by clicking here.

Sealing for Extreme Cold: Best Practices for Static Seals

As published in Pumps & Systems Magazine, July 2018

Co-written By: Chett Norton, C.E.T.

 

Flexible graphite and PTFE are commonly used in cryogenic sealing. Natural gas popularity is growing exponentially because of its low cost, low risk to transport and store, and its status as one of the cleanest burning fossil fuels. With increasing global pressure to reduce greenhouse gas emissions, the need to meet growing energy demands while reducing these emissions is more important than ever.

Click here to read entire article.

Check Valves: Back to the Basics

As published in Pumps & Systems Magazine, July 2018

By: Bruce Ellis

 

Check valves, or one-way valves, are designed to stop back-flow and, ultimately, to protect pumps and compressors. They are available in several styles and sizes, from 1/8 inch to as large as may be required. Check valves are found in many industries and with various applications ranging from municipal water to mining and natural gas. The three most common types are swing check valves, double-door check valves and silent spring-assisted axial flow check valves.

Click here to read entire article.

Sanitary Valves – keeping it clean!

April 26, 2018

By: Bruce Ellis and Sylvia Flegg

 

There is an ever-increasing demand for dependability, efficiency and energy savings when selecting valves – as it needs to be the correct one! And a function that is often overlooked is the valve’s ability to minimize energy consumption.

 

Principles of Operation

An essential element in the design of pumping systems is the proper selection of the pump discharge check valve, whose purpose is to automatically open to allow forward flow and automatically return to the closed position to prevent reverse flow when the pump is not in operation.

Check valves are generally made up of plastic or metal. In most sanitary applications you will find the composition of the valve being 316L stainless steel and are CIP (Clean In Place) capable.

Cracking pressure (the minimum upstream pressure at which the valve will operate) is also an important design element of the sanitary check valve.

When selecting a sanitary check valve, you should look at the following criteria:

  • Non-slamming characteristics
    The amount of time it takes for the Check Valve to close and the way in which the disc travels from the open to the closed position.
  • Disk design
    Location is a key factor here.
  • Cost
    Is the initial purchase price competitive? The main things a buyer should consider are system downtime, valve location and cost of parts and labor.
  • Application
    The importance of each selection criteria must be weighed to make an informed selection on the valve best suited for the application.

 

Our solution – the DFT® DSV® Sanitary Check Valve
The DSV® Sanitary Check Valve is an edge/centre guided disc design valve for applications where CIP designs are required.

They are used mainly in food, chemical & cosmetic factories. These valves are available in horizontal (self-draining) and vertical styles.

The DSV® valve meets USDA and 3A Sanitary Standards and Pharmacopeia (USP Class VI) certifications.


The valve itself is manufactured from 316 stainless steel polished to 25RA and is available polished to 15RA and is fastened with a quick release clamp and elastomeric body seal to permit fast and easy access to the internals. The disc and seat are lapped to provide excellent shutoff.

 

Features:

  • 1/2” to 4” line size
  • 150 CWP, 108 ASME pressure class
  • Meets 3A Standard 58-01
  • CIP (Clean In Place)
  • Clamped ends
  • 316L body and seat
  • 316 disc, spring & guide assembly
  • 32 Ra internal surface finish (#4 Ground Finish)
  • Electropolished spring (.16 to .66 psig cracking pressure)
  • EPDM body seal (300°F max temp.)
  • Edge-guided disc (1/2” thru 2”)
  • Edge/Center-guided disc (2-1/2”, 3”, 4”)
  • Spring assisted silent closing, non-slam
  • Tight shutoff – lapped disc & seat
  • Horizontal or vertical installation

 

Options:

  • 15 Ra internal finish
  • Tuf-Flex® or Viton® body seal
  • Straight thru inline or offset inlet/outlet

 

Download the DFT® Silent Check Valve 6-page Brochure now!

8 Gasket Myths – Debunked

March 13, 2018

By: Chett Norton, C.E.T.

 

As a gasket application’s engineer, I spend a lot of time speaking with people on the phone or in person on site discussing gaskets. Whether it is material selection, installation or trouble-shooting gasket failures, there are many common things I hear people talk or ask about. So, this month I am writing to try and clear the air and help shed some truth on common things that are either thought to be true or practiced in field.

 

1. Thicker gasket material is better

People generally request thicker material due to an excessive gap or misaligned flanges. They think that the thicker material will fill the void; however, what they may not be aware of is creep/relaxation. Gasket creep/relaxation is somewhat linear (depending on the material) and the amount of material creep increased with gasket thickness. Want less creep, go thin or go home! Also, things such as torque retention, higher blow-out resistance and leakage (through gasket permeation) are much better with thinner materials.

 

2. Gasket colours indicate the materials are the same

”I’ve always used a blue gasket, so I need a blue gasket” is a common phrase heard time and time again. Gasket colour is generally meaningless. But in some cases, competitors may choose the same colour for their entire product line. So, to be sure, instead of asking for a specific colour, verify the pressure, temperature and media so that the proper material will be selected for your application.

 

3. Torque values are the same for all gasket materials

All torque values are not the same. Firstly, when looking at torque charts please be sure to read the fine print to verify bolting material, % of bolt yield used, K-Factor used and the maximum allowed compression for each material. For most soft gaskets, the maximum gasket compression is 15,000psi, however for semi-metallic gaskets like SWG’s and Kammprofile’s the maximum compression is more like 20,000-30,000 psi so there is good chance you could possibly crush the gasket if you use an incorrect value.

 

4. Leaking gaskets just need to be retightened

If a gasket is leaking, do not retighten. Particularly with soft gasket materials, hot torqueing is very dangerous. Once compressed gaskets reach an elevated temperature they can become brittle and further tightening can cause the gasket to crack. This can further increase the leak or even worse, cause a gasket blow out! If a gasket is leaking, it should be replaced!

 

5. All gaskets are made the same and perform the same

Not true. There are many types of methods for the manufacturing of sheet materials such as the calendar method, skived method and even the beater add which all give the material different properties. The properties shown on gasket technical data sheets are for QC purposes and allow you to somewhat compare “apples to apples” however they do not actually give you performance data but are merely indicators on how they may perform in certain applications. There are some tests out there like the FSA Steam test which are representative data on how the product will perform in steam applications. There are others for specific properties so be sure you are understanding the correct test values and how they will benefit or affect your sealing application. And you may want to use the materials ASTM F104 line call to truly compare gasket materials because it is the preferred method to ensure you are on a level playing field.

 

6. Grease or lubricant is a good way to hold a gasket in place during the installation process

Getting a gasket into position during an installation can be tricky, so sometimes people use a dab of grease or lube on the gasket to get it to stick to the sealing face during bolt up. This is not a good idea for two reasons: the grease can chemically attack the gasket material and it also lubricates the sealing face which allows the gasket to be pushed out easier by the system pressure. Now remember, we are trying to compress the gasket enough to fill the flange serrations and have them “bite into” the gasket to resist being pushed out by the system pressure. Putting grease on the gasket negates what we are trying to achieve…..so don’t do it!

 

7. Softer materials seal better

Firmness is also referred to as the materials ability to resist flow. Softer materials are not necessarily better, but they are good for applications where the material needs to confirm to worn flanges or uneven flanges. It is quite common for the material to have more creep when softer, so this may not be a desirable trade off when choosing the material. For higher temperature and higher pressure applications, material hardness and sealing surface finish need to be strongly considered.

 

8. Gasket installation procedure doesn’t affect sealing performance

Gasket installation is the most influential factor that affects sealing performance. If you do not install the gasket using a correct method such as the Legacy Method (see figure 1), an alternative method listed in ASME PCC-1, Appendix F or the method recommended from the manufacturer, you run the risk of not getting the most out of your gasket. Using a proper installation method helps the installer bring the flanges together in parallel which lessens the risk or crushing the gasket or unevenly loading the gasket which can cause leaks. Furthermore, it ensures that the load applied to the gasket (via torqueing) is correct and consistent which is important in gasket sealing performance.

 

 

 

 

 

 

 
 

 

 

 

Figure 1. Legacy Method Bolt Tightening Pattern

 

So, there you have it, hopefully this sheds some light on some common myth’s when selecting or installing gaskets. If you have one that wasn’t covered, feel free to drop me a line at [email protected] or @TFCGasketguru on twitter and we will get you on your way to better sealing!

Until next time, keep the fluid between the pipes.

Download the Durlon® Gasket Manual now!

How Gaskets are Measured

February 23, 2018

By: Chett Norton, C.E.T. and Sylvia Flegg

Gaskets come in all shapes and sizes: round, oval, rectangular etc. Accurate measurement size is important because it ensures that the gasket will fit properly and will not get in the way of the installation. Additionally, measurement is managed by QC, assuring that the gasket will comply with either the customer specifications or tolerances given by specific cut gaskets standards such as ASME B16.21 & EN1514-1. To help illustrate some of these points I am going to give you two specific examples of what to measure and what to avoid doing.

 

Ring gaskets are quite simple to measure because you only need to verify two measurements: Inside Diameter (ID) and Outside Diameter (OD). Ring gaskets are generally used in raised face (RF) flanges as the gasket is centered inside the bolts. Generally, it is not recommended to use ring gaskets in full face flanges as they are thinner and more fragile. Since the ring gasket OD does not line up to the edge of the flange, any bending of the flange (flange rotation) caused by tightening bolts could result in severe damage.

Full face gaskets are a bit more difficult to measure because there are five things that you need to verify correctly: Inside Diameter (ID), Outside Diameter (OD), Bolt Circle Diameter (BCD), bolt hole diameter and the number of total bolt holes.

 

Full face gaskets are commonly found in flat faced flanges but are also occasionally used in raised face (RF) flanges. For ease of use in RF flanges, installers insert the gasket between the two flanges and insert two or more bolts to align the gasket before installation. Although using a full face gasket in a RF flange adds cost to the installation, this minimizes the gasket from being improperly centered and makes the installation process easier.

Measurement Methods

The most common hand tool used for measurement is a tape measure or ruler. Either can easily allow the person to check the ID and OD of the gasket by visually verifying the dimensional increments on the tool. Bolt holes and the bolt circle diameter of a gasket are a little trickier; however consistent measurements can be obtained with a little practice. These types of measurement tools should not be used when high precision measurements are required.

Vernier Calipers are another handheld tool that are much more accurate than rulers and tape measures. The digital read allows measurements to as low as 0.001” increments. Vernier calipers come in various size ranges, so if you have range of gaskets sizes to measure, there is a good chance that may need two or three sets to cover the full range of sizes that you need.

The two methods I have listed above both have one major disadvantage in common when it comes to measurement – human error. When trying to measure gaskets, they can become “egg shaped” or oval. The simple way to eliminate this error is to use a jig or a pass/fail fixture that allows you to insert the gasket without having to physically measure it. If the gasket fits, it passes and if the gasket does not fit then it is rejected. The down side to this type of fixture is that it can be costly to make and you will need a fixture for each individual gasket size.

 

So there you have it! I hope this gives you some oversight on what to look for, or consider when determining gasket measurement.

Until next time, keep the fluid between the pipes!

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