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How to get Vespel® CR-6100 in a new pump?

Frequently Asked Question:

“Are the OEMs using Vespel® CR-6100?” is a question we hear every month. The answer is definitely, “yes.” All of the major API pump manufacturers use Vespel® CR-6100 for both new pumps and aftermarket upgrades.

A related question: “If Vespel® CR-6100 is so great, why don’t the OEMs include it as a standard material?”

To answer that, we need to look at how pumps are usually purchased…

Most pumps are sold into projects. The EPC contractor generally selects the pump with the lowest price which meets the bid specification. Therefore, if the bid spec allows bronze or cast iron wear rings, the OEM will probably quote bronze or cast iron because they are the cheapest materials. These materials might result in a higher life-cycle cost, but procurement personnel will not care if their decision is driven by the initial price.

Put it in the Bid Spec

If you want to maximize your pump reliability and efficiency, specify Vespel® CR-6100 for the stationary wear components in your next project. When it is part of the specification, the OEMs are happy to quote and supply Vespel® CR-6100.

If your company does not allow using brand names in the project specification, you can use the generic description for Vespel® CR-6100 from API610, Table H.3: PFA/CF reinforced composite, 20% mass fraction random X-Y oriented carbon fiber. For clarity, you can add the note “one example of which is DuPont™ Vespel® CR-6100.”

Direct Questions to Boulden

If there are any questions from the Project Engineer, EPC contractor, or OEM, please ask them to contact Boulden. We will be happy to answer any questions they have and make sure that the Vespel® CR-6100 is used correctly throughout the project.

In short, if you want Vespel® CR-6100 wear rings, vertical pump shaft bearings, or throttle bushings in your new pumps, all you have to do is ask–i.e. spell it out in the bid spec. Until next time, if you need any material for your pumps, we have a wide range of sizes in stock and ready for immediate shipment.

Helpful Links:

Boulden Installation Guide for Vespel® CR-6100

Standard Stock Sizes of Vespel® CR-6100

Vespel® CR-6100 Product Data Sheet

Vespel® CR-6100 Machining Guide

2MW Boiler Feed Pump Case Study

Amine Stripping Pump Case Study

 

Today’s Photo

Lanzarote, Spain

Lanzarote, Spain

Upgrading Pumps With Composite Wear Components: Part 3

Part 3: Reduce Clearance – Improve Pump Efficiency

Welcome to Part 3 in our series on upgrading pumps with composite wear parts.

In the first part of this series, we discussed how upgrading your pumps with composite wear parts can help avoid galling and seizing. Because composite parts do not gall or seize like metal parts, this allows you to reduce the clearance at these components in your pump.

In Part 2, we discussed how reducing the clearance at the wear rings, throttle bushings, and center-stage bushings creates a stabilizing force in your pump called The Lomakin Effect. This force helps to reduce vibration and shaft deflection, leading to longer seal and bearing life in your pumps.

Today, we will discuss how reducing the clearance in your pump also improves pump efficiency.

Centrifugal Pump Background

According to a major centrifugal pump OEM, energy consumption accounts for 44% of the life cycle cost of a centrifugal pump. You can reduce this cost by upgrading the wear components to a composite material like Vespel® CR-6100 and reducing the clearance in your pump.

The specific components where you want to reduce the clearance are the pump wear rings, inter-stage rings, center-stage bushing, and throttle bushing. These components form the barriers between high-pressure and low-pressure areas within the pump. The differential pressure across these components creates internal recirculation within the pump, resulting in a loss of pump efficiency (Figure 1).

Loss of pump efficiency

Leakage past the wear rings (QL) creates efficiency loss

 

 

 

 

 

 

When you upgrade these components to Vespel® CR-6100, you can typically reduce the clearance by 50% compared to the API minimum for metal parts. If you reduce the clearance by 50%, you reduce the internal recirculation by approximately 50%, leading to a significant efficiency gain.

Which Pumps Produce the Biggest Gains?

If we consider only efficiency gains, horizontal multi-stage pumps usually offer the best return on investment from an upgrade to Vespel® CR-6100 with reduced clearance. These pumps have multiple leak paths across wear rings, inter-stage rings, center bushings, and throttle bushings. Because they have many stages, these pumps also tend to consume a lot of power. Consider the following cases where process plants have reduced the operating costs of their multi-stage horizontal pumps:

  • A power station upgraded a 3MW boiler feed water pump with Vespel® CR-6100 along with the Boulden PERF-Seal™ design and reduced clearance and recorded a 7% efficiency gain compared to a newly rebuilt pump with original clearances.
  • A refinery upgraded their hydrocracker charge pumps with Vespel® CR-6100 along with the Boulden PERF-Seal™ design and reduced clearance and recorded 4% more throughput to their hydrocracker-a hugely profitable upgrade.
  • A product pipeline company upgraded their LPG shipping pumps with Vespel® CR-6100 and reduced clearance, resulting in a 4% efficiency gain.

Another area to consider is process pumps which are marginally undersized, requiring parallel pump operation to achieve 100% of the target process rate. Sometimes, a modification as simple as reducing the wear ring clearance can get you back to one-pump operation with a full-capacity spare pump.

The PERF-Seal™

To further increase the efficiency gain associated with reduced clearance, the components can be modified with the Boulden PERF-Seal™ design. Internal testing has shown that the PERF-Seal™ creates an additional reduction in flow across throttle bushings, center-stage bushings, and wear rings beyond what can be achieved with reduced clearance alone.

Conclusion

When you eliminate the metal-to-metal contact surfaces in your pumps and use Vespel® CR-6100 stationary wear components, you can then reduce the clearance. This reduction in clearance improves pump efficiency and lowers the operating cost of the pump. Numerous field examples exist where customers have saved tens of thousands of dollars on their annual pump operating costs with this simple upgrade.

If you have a pump where improved efficiency will save you money, contact Boulden today. We have a huge inventory of Vespel® CR-6100 standard sizes in stock ready for immediate shipment almost anywhere in the world.

For application and installation details, download the Boulden Installation Guide for Vespel® CR-6100.

Today’s Photo

Cape Town, South Africa

Cape Town, South Africa

Amine Stripping Pump Case Study

Vespel® CR-6100 with the PERF-Seal® design survived where metal parts failed

In case you missed it…

The October 2018 issue of Hydrocarbon Processing featured a case study of Vespel® CR-6100 with the PERF-Seal®  design installed in a 2.7 MW amine stripping pump.

Amine Stripping Pump
2-Stage, 2.7MW, 4500 RPM Amine Stripping Pump

Amine pumps upgraded for improved operations and reliability

An excerpt…
The amine circulation pumps are controlled to gradually ramp up to operating speed. During this ramp-up period, the pumps produce insufficient head to generate any flow into the gas absorber. Therefore, the pumps must run on a minimum flow bypass back to the suction header. This flow is controlled by a minimum flow line valve (MFLV), which should be opened before startup and then closed once full-speed operation of the pumps is established.
With a steam turbine driver, ramping up to 4,500 rpm requires approximately 15 min, which is far too long to run the pump at zero flow.
Periodically over the past 10 yr, the MFLV has been opened too late during the startup procedure, which has led to the pump seizing at the center bushing and non-drive-end (NDE) and drive-end (DE) throat bushings (FIG. 1). These components have the tightest clearance and are, therefore, the first metal-to-metal contact points inside the pump.

To read the full case study, visit the Boulden website:
https://www.bouldencompany.com/dupont-vespel/case-studies/amine-pumps
If you have a pump running at low flow, or suffering from operational issues, running dry, or seizing contact Boulden today. We can provide all of the information you need to upgrade your pump and reduce your operational headaches. We have the material you need in stock and ready for immediate shipment almost anywhere in the world.

Helpful Links:
Boulden Installation Guide for Vespel® CR-6100
Standard Stock Sizes of Vespel® CR-6100
Vespel® CR-6100 Product Data Sheet
Vespel® CR-6100 Machining Guide
3MW Boiler Feed Pump Case Study

 

Today’s Photo

The Acropolis in Athens Greece
The Acropolis in Athens Greece

 

Catacarb® Pump Case Study

A single installation of Vespel® CR-6100 saved a lot of money and troubles.

Several years ago, a refinery upgraded a Catacarb® pump with Vespel® CR-6100 case rings. The pump was a single-stage, between bearings, double suction pump. Catacarb® is a mixture of potassium carbonate and other chemicals which is used to strip gases such as CO2 and H2S from hydrocarbon streams.

For two years after the installation, the pump ran perfectly, and no one thought about the Vespel® CR-6100 wear rings in the pump.

 

Then, one day…

One day, the Operators heard one of the Catacarb® pumps making a loud pounding sound. They shut it down and switched to the spare. The noisy pump stopped without issue. The pump did not seize, the seals did not leak, and there was no release of the process to the atmosphere.

When the pump arrived in the shop, the Maintenance crew found the problem. A piece of metal had broken from an upstream valve, lodged itself in the impeller and proceeded to pound against the pump volute. The impeller suffered substantial damage shown in Figure 1:

Damaged Impeller

Figure 1: Impeller damaged by a piece of metal lodged in the pump

Disassembly revealed that the pump had been fitted with Vespel® CR-6100 case rings. The rings showed signs of contact and perhaps a negligible amount of wear, but remained in working condition as shown in Figure 2:

Vespel CR-6100 Case wear ring

Figure 2: Vespel® CR-6100 case wear ring after the incident

 

Conclusion

According to the refinery Maintenance team, without the Vespel® CR-6100, the pump would have likely seized, causing severe damage to the pump, along with the potential for seal failure and leakage of the process to the atmosphere. Instead, the plant continued to run. How much money did they save? How much trouble did they avoid? Fortunately, no one will ever know. Because the pump did not seize, the only cost was a standard repair plus a new impeller.

If you want to help your pumps avoid seizure, contact Boulden today. We have Vespel® CR-6100 in stock in a wide range of sizes in the USA, Europe, and Singapore and we can assist with any application or design questions you have. If you know what you need, just request a quote.

Until next time, Merry Christmas, enjoy the holidays and be safe.

 

Helpful Links:

Standard Stock Sizes of Vespel® CR-6100

Vespel® CR-6100 Product Data Sheet

Vespel® CR-6100 Machining Guide

3MW Boiler Feed Pump Case Study
Today’s Photo

Marché de Noël, Strasbourg, France

Marché de Noël, Strasbourg, France

 

 

 

 

Contact Us Today To Learn More About Vespel and Boulden Company!

 

 

 

 

 

 

 

 

Reformer Feed Pump Case Study

A long-term success story

Almost 10 years ago, a refinery in Europe upgraded their Reformer Feed pumps to DuPont™ Vespel® CR-6100. Last month, we checked in to see how the pumps are running.

The Application

The Reformer Feed pumps are 10-stage, axially-split, between-bearings pumps (API Type BB3), running at 2950 RPM. The product is naphtha at 185 C (365 F). There is one pump in the service, plus a spare rotor in the warehouse.

Problems in the Past

Marginal suction conditions make this a very tough service. The pumps take suction from a stabilizer tower bottom with NPSHA of only about 3 meters (10 feet). Due to the low NPSHA, it is very easy for the fluid to vaporize in the pump during start-up, causing the pump to run dry. This was formerly the normal reason for repairs due to the metal wear parts galling and seizing. If the metal parts did not seize, the throttle bushing would wear out, causing seal failures at the non-drive end.

Vespel CR-6100 wear parts

Vespel CR-6100 wear parts are installed as “inserts” into the existing metal parts for axial split pumps running at elevated temperatures.

Vespel® CR-6100 Survives

In 2009, the first pump in the service was upgraded with Vespel® CR-6100 case wear rings, center bushing, and throttle bushing. By eliminating the metal-to-metal contact points in the pump, the risk of pump seizure was essentially eliminated. Once the original pump upgrade proved successful, the spare rotor was also upgraded, but it has never been installed. The original pump upgraded is still running today. The refinery engineer commented:

We know for sure the product has vaporized in the pump at least 3 times since the upgrade, with seal failures as the only damages. We haven’t exchanged the rotor yet, although we have the spare rotor upgraded in 2010 in the warehouse. So far, no one expects the rotor to be exchanged.

As an added bonus, the site notes that they achieved a significant efficiency increase with the upgrade, which allowed an increase in unit throughput of 10%.

Vespel CR-6100 Conclusion

Where the refinery suffered with multiple failures of metal parts in the past, the Reformer Feed pump has now been running nearly 10 years with Vespel® CR-6100. The upgrade has paid for itself many times over with better reliability, efficiency, and ease of operation.

If you have a service causing you headaches, or if you are looking to increase throughput on one of your feed pumps, contact Boulden today. We have Vespel® CR-6100 in stock in a wide range of sizes in the USA, Europe, and Singapore and we can assist with any application or design questions you have. If you know what you need, just request a quote. Until next time, be safe.

 

Helpful Links:

Standard Stock Sizes of Vespel® CR-6100

Vespel® CR-6100 Product Data Sheet

Vespel® CR-6100 Machining Guide

3MW Boiler Feed Pump Case Study

Today’s Photo

Moselle river between Luxembourg and Germany

Moselle River Between Luxembourg and Germany

Moselle River Between Luxembourg and Germany

Contact Us Today To Learn More About Vespel and Boulden Company!

 

 

 

 

 

 

 

 

VibVue–Visualizing Vibration

What if You Could Actually SEE Vibration?

Background

Mechanical Solutions, Inc. is well-known for their ability to accurately diagnose difficult rotating machinery problems, AND to provide an engineered, implementable solution. They also have 22 years in solving problems using high-speed video. Recently, those two threads came together to bring the VibVue™ system to market through MSI’s Envision Motion division.

What is VibVue™?

This exciting new technology uses high-speed video to analyze vibration on a pixel-by-pixel basis, and then to visualize that vibration for the entire machine through significant amplification (up to 1000 times!) at distinct frequencies. The VibVue™ Pro system facilitates full-machine analysis and visualization at frequencies over 600Hz, enabling diagnoses involving many multiples of running speed, such as vane and blade pass. The resultant high-definition videos provide a comprehensive, realistic, data-enhanced view of the machine or piping system’s motion for problem identification and solution determination.

For example, this video of a pipeline station vent is amplifying vibration at 418 Hz. VibVue™ lets you find the needle in the haystack. To learn more, head to the Envision Motion website.

Whole Installation of the VibVue

 

 

 

 

 

 

 

Close Up of the Station Vent – Vib Vue

 

 

 

 

 

 

 

To learn more about MSI’s capabilities, including an extensive array of case studies featuring their rotating machinery solutions, go to the MSI website.

Come See Boulden

Boulden is working with MSI to help introduce this new technology. Come check out VibVue™ at the Boulden booth 1434 at the Texas A&M Pump and Turbomachinery Symposium in Houston next week.

As always, Boulden will also have Vespel® CR-6100, the Boulden PERF-Seal™ design, and some other new things for you to see.

If you can’t make it to the show, Contact Us for more information.

 

Helpful Boulden Links:

Standard Stock Sizes of Vespel® CR-6100

Vespel® CR-6100 Product Data Sheet

Vespel® CR-6100 Machining Guide

3MW Boiler Feed Pump Case Study

Today’s Photo

Mount Vernon was George Washington’s plantation house. situated on the banks of the Potomac River in Fairfax County, Virginia.

Contact Us Today To Learn More About Vespel and Boulden Company!

 

14 Reasons to Avoid Increased Wear Ring Clearance

If you increase the clearance, the long-term reliability and efficiency of the pump will suffer.

Happy Summer!

We hope you have had a chance to enjoy your summer holidays. From New Orleans to Narvik, it’s hot out there, so be safe, and wear sunscreen.

In our messages, we frequently highlight how Vespel® CR-6100 does not seize and therefore allows you to reduce the clearance at the wear parts in your pumps: wear rings, inter-stage rings, throttle bushings, and center bushings.

Today we want to look at things from another perspective–negative effects which can happen to your pump when you increase the clearance at the wear parts.

 

What can happen when you increase clearance?

If a process plant has a problem with a pump seizing during operation or galling during commissioning, the traditional response has been to increase the clearance at the wear parts.

Metal Case Ring After a Boiler Feed Pump Seizure

 

Although increasing the clearance might make the pump operable in the short term, there are several negative consequences from increased clearance.

Hydraulic Effects Mechanical Effects
Lower head Reduced rotor stability
Lower flow Potentially higher vibration
Lower efficiency–increased power consumption Potentially higher shaft deflection
Higher NPSHR–greater risk of cavitation Increased risk of shaft breakage
Higher motor load Potentially shorter seal life
Need to run steam turbines at higher speed Potentially shorter bearing life
Higher likelihood of needing to run pumps in parallel Higher risk of motor over-heating or tripping from excessive load

So, while you don’t want your pumps to seize, increasing the clearance can create some major issues. At a minimum increased clearance drives up the operating cost of the pump and likely compromises the long term reliability of the machine.

 

The Poster Pump

A while back, one of our clients had an 11-stage horizontal pump which was originally supplied with metal wear components. The pump seized soon after start-up, and the recommendation from the OEM was to increase the clearance. The pump seized again. The second recommendation was to use a “non-galling” metal alloy to address the problem. The pump seized again. The clearance was increased one more time. When the pump was started again, the overall pump vibration levels were beyond alarm limits. The multiple increases in clearance had resulted in a loss of rotor stability to the point that the pump was no longer operable.

The end of the story will be in our next email…

 

Conclusion

Until next time, if you have a pump in your shop which has galled or seized, contact Boulden to discuss an upgrade to Vespel® CR-6100. We will be happy to work through the details of the upgrade with you and we have material in stock and available for immediate shipment.

 

Helpful Links for Vespel and Pump Case Studies:

Standard Stock Sizes of Vespel® CR-6100

Vespel® CR-6100 Product Data Sheet

Vespel® CR-6100 Machining Guide

3MW Boiler Feed Pump Case Study

Today’s Photo’

Rossio Square in Lisbon Portugal with famous wave pattern stone pavement.

Contact Us Today To Learn More About Vespel and Boulden Company!

 

 

 

 

 

Make Your Vertical Pump Shaft Bearings Last Longer

DuPont™ Vespel CR-6100 resists seizing, can run dry, has high impact resistance, and a low wear rate for a long life under a wide range of process conditions.

Vertically Suspended Pumps

Vertically suspended pump types (API types VS1-VS7) use long, flexible shafts which are supported by a series of product-lubricated shaft bearings. Vespel® CR-6100 is a great upgrade for these components.

 

Typical Vespel Services

Vertically suspended pumps can be divided into two general categories: discharge through column (API Types VS1, VS2, VS3, VS6, and VS7) and separate discharge (VS4 and VS5).

 

Discharge through column pumps tend to be used in light, flashing products like butane, LPG, and natural gas liquids, or in water condensate or cooling water intake service. In flashing services, it is not uncommon for these pumps to run dry temporarily at start up, which can be a challenge for the shaft bushings. In many of these pumps the flexible shaft can create very large loads, leading to high wear rates of traditional materials.

 

Separate discharge pumps tend to be used as sump pumps. In API Type VS4 pumps, the shaft bearings can run dry at start-up until the flushing fluid arrives. Sometimes, the external water flush is turned off; sometimes the flush lines from the process fluid are plugged; sometimes the bearing grease is insufficient. In a chemical sump, the mix of chemicals can cause corrosion issues.

Vespel® CR-6100 Replaces Traditional Materials

Most vertical pump shaft bearings are made from either bronze/cast iron, carbon/graphite based materials, or stainless steel alloys. Bronze/cast iron bearings can have a high wear rate. Carbon/graphite bearings can break. Stainless steel bearings can seize.

 

Vespel® CR-6100 can replace all of these materials in process conditions from cryogenic to 500 F (260 C). Vespel® CR-6100 is low friction with a low wear rate. It is durable and impact resistant so it resists breakage during installation, transport, and operation. Plus, Vespel® CR-6100 does not seize like metal parts and is capable of surviving the run dry conditions which can occur with the flashing process fluids.

 

Documented Results

Consider the results from a long term study at an oil refinery. The plant upgraded 22 vertical pumps to Vespel® CR-6100 wear parts. The pumps were operating in light hydrocarbons, flare knock out drum, and several stop/start services like product transfer, comprising many “bad actors” in the plant. Looking at the number of repairs within this population for 5 years before Vespel® CR-6100 and 5 years after, the plant found the following.

 22 Vertical Pumps Number of Pump Repairs MTBR for the Population
5 Years Before

Vespel® CR-6100

40 2.75 years
5 Years After 

Vespel® CR-6100

8 13.75 years

Final Notes

Next time you are rebuilding a vertically suspended pump, consider upgrading the shaft bearings to Vespel® CR-6100. Contact Boulden with your process conditions and we will be happy to let you know if Vespel® CR-6100 is a good fit for your pump.

 

The Vespel® CR-6100 installation guide will walk you through the installation process. Vespel® CR-6100 is easy to machine and install, and Boulden is always happy to help if you have any questions. Finally, we have large quantities of Vespel® CR-6100 in stock and ready for immediate delivery in North America, Europe, and Southeast Asia.

 

Helpful Vespel Links:

Standard Stock Sizes of Vespel® CR-6100

Vespel® CR-6100 Product Data Sheet

Vespel® CR-6100 Machining Guide

3MW Boiler Feed Pump Case Study

 

Todays Photo

Bernkastel-Kues, Germany

 

Contact Us Today To Learn More About Vespel and Boulden Company!

The Final Installation Steps: Length and Clearance

Upgrading pumps with composite wear componentsSetting the final dimensions of your DuPont™ Vespel CR-6100 component

Review

We have discussed how to measure your pump, prepare the metal parts, and establish the press fit for your Vespel® CR-6100 installation. The final two dimensions you need to establish are the part length and the clearance.

The Part Length

Vespel® CR-6100 has an extremely low coefficient of thermal expansion in the radial plane (perpendicular to rotation). This is one of the principal reasons it performs so well in centrifugal pump components. The low coefficient of thermal expansion is achieved through the use of radially-oriented, long carbon fibers.

Conversely, the coefficient of thermal expansion along the axis is relatively high. Therefore, the part length for a Vespel® CR-6100 component should account for the axial thermal expansion at operating temperature. Table 4 of our installation guide provides the details on how to make this adjustment.

Table 4 of our installation guide provides the details on how to make this adjustment.

The Clearance

The clearance for the part is set depending on the diameter and component type. Tables 2a and 2b in the installation guide show the clearance recommendations for horizontal pump components such as pump wear rings, throttle bushings, center bushings, inter-stage rings, balance bushings, and throat bushings.

Tables 2a and 2b provide recommended minimum clearance for horizontal pump components.

Tables 3a and 3b show the clearance recommendations for vertical pump components like vertical pump shaft bearings, wear rings, and throat bushings.

Tables 3a and 3b provide recommended minimum clearances for vertically suspended pump parts.

The best way to set the clearance is to press the component into place, and then final machine the bore to the desired clearance. This is shown in steps 5a-7a in our installation guide, pages 8-9.

Where final machining after the press fit is not practical, you can design the component to have the correct clearance after the press fit. For most component geometries, you can assume the Vespel® CR-6100 will reduce at a 1:1 ratio with the press fit. This method is shown in steps 5b-7b in our installation guide, page 9.

Some sites have implemented a hybrid method. They measure the inside diameter of the Vespel® CR-6100 case wear ring after installation, and then machine the metal impeller wear ring to set the desired clearance.

Conclusions

Installing Vespel® CR-6100 is an easy upgrade to make your pumps more reliable, safe, and efficient. Follow the steps in our  installation guide and you can make your pump even better than the day it was new. If you need material, Boulden carries inventory of stock sizes in the USA, Europe, and Singapore.

Until next time, please feel free to contact Boulden with your application details or to request a quote. We’ll be happy to answer any questions you might have.

 

Helpful Links:

Standard Stock Sizes of Vespel® CR-6100

Vespel® CR-6100 Product Data Sheet

Vespel® CR-6100 Machining Guide

3MW Boiler Feed Pump Case Study

Today’s Photo

Rock of Gibraltar – was one of the Pillars of Hercules and was known to the Romans as Mons Calpe.

 

Contact Us Today To Learn More About Vespel and Boulden Company! 

The Interference Fit – Setting the interference fit value for DuPont™ Vespel CR-6100

The interference fit value for DuPont™ Vespel CR-6100

Review

We have discussed how to measure your pumps and prepare the metal parts. The next step is to machine the DuPont™ Vespel® CR-6100 part to have the correct dimensions.

Remember, Vespel® CR-6100 is used for stationary wear parts like wear rings, throttle bushings, and vertical pump shaft bearings. The rotating components running against the Vespel® CR-6100 remain metal. The Vespel® CR-6100 components are installed with an interference fit (aka “press fit”).

 

Installation Guide for Vespel CR-6100

The Boulden Installation Guide for Vespel® CR-6100 Tables 1a (Imperial) and 1b (Metric) outline the interference fit values for a Vespel® CR-6100 component based on diameter and the pump operating temperature.

If you only want the right value, follow the guide. You can stop reading and contact Boulden whenever you need material or if you would like to request a quote. If you want to know how we arrived at the values, continue reading.

 

Low Coefficient of Thermal Expansion

Vespel® CR-6100 has an extremely low coefficient of thermal expansion–about 60% lower than carbon steel in the radial plane. This property is one of the reasons Vespel® CR-6100 can survive pumps running dry and avoiding seizure.

The low coefficient of thermal expansion is a main factor in the interference fit value. At elevated temperatures, the metal parts will thermally expand more than the Vespel® CR-6100 parts. Therefore, as pump operating temperature increases, the interference fit increases.

 

Vespel CR-6100 Low Modulus of Elasticity

Vespel® CR-6100 parts press in relatively easily due to a very low modulus of elasticity. Vespel® CR-6100 can be used in temperatures up to 500 F (260 C). At maximum operating temperature, the recommended interference fit can be quite high. Due to the low modulus, the material generally presses in without issue.

 

Small Pilot Fit

To facilitate the large interference fit, machine a small pilot or “step” on the leading edge (Figure 1) of the Vespel® CR-6100 component. This will help the part sit squarely in the bore as it is being pressed in (Figure 2).

Figure 1: Pilot Fit on leading edge to facilitate press fit

Figure 2: Press fit operation

No Pins or Screws Required

Once Vespel® CR-6100 is installed with a press fit and a shoulder to retain the part against differential pressure, no further retention of the components is required. There are thousands of pumps running for many years with Vespel® CR-6100 components without retaining pins or screws.

If you insist on using retaining pins with Vespel® CR-6100, contact Boulden and we will discuss the possible designs given your part geometry.

 

Conclusions

When installing Vespel® CR-6100, make sure you are using the correct interference fit. Download our installation guide for the full installation procedure. If you need material, Boulden carries inventory of stock sizes in the USA, Europe, and Singapore.

Until next time, please feel free to contact Boulden with your application details or to request a quote. We’ll be happy to answer any questions you might have.

 

Helpful Links:

Standard Stock Sizes of Vespel® CR-6100

Vespel® CR-6100 Product Data Sheet

Vespel® CR-6100 Machining Guide

3MW Boiler Feed Pump Case Study

If you need any material or have any questions. Please contact us today. Until next time.

Contact Us Today To Learn More About Vespel and Boulden Company!

 

 

 

 

Todays Photo

Grand Canyon, Arizona USA

 

Boulden Company – Conshohocken, PA, USA | 1-610-825-1515

Boulden International, S.ar.L – Ellange, Luxembourg | +352 26 39 33 99