Tag Archives: vertical pump shaft bearings

Prepping Your Metal Parts

Prepare your pump parts for an upgrade to DuPont™ Vespel CR-6100

Review on Pump Parts and upgrading to Vespel CR-6100

The National Geographic Channel used to run a show called Doomsday Preppers where survivalist families would prepare for apocalyptic disasters and societal collapse. Although that sounds like a lot of fun, at Boulden, we are more concerned with helping your pumps survive adverse process conditions with an upgrade to DuPont™ Vespel® CR-6100.

 

Last month, we outlined the measurements required for a Vespel® CR-6100 installation. When you have decided to go forward with the upgrade, the first step will be to prepare the metal parts to facilitate the installation.

 

Start with a Little Chamfer

Vespel® CR-6100 is used for stationary wear components–throttle bushings, case wear rings, center-stage bushings, inter-stage case rings, vertical pump shaft bearings, throat bushings, agitator bearings, API separator bearings-basically any product lubricated wear part.

 

The material is installed with a significant press fit. To facilitate the press fit operation, the metal bore into which you will be pressing the Vespel® CR-6100 requires a small chamfer or radius (Figure 1). It is very important that any corners or sharp edges are fully broken and smoothed with a stone so that the metal edge does not remove material from the outside surface of the Vespel® CR-6100 during the press operation.

Figure 1: Chamfer or Radius Leading Edge to facilitate press fit. (Note shoulder on low-pressure side.)

 

 

 

 

 

 

 

 

 

Make Sure There is a “Shoulder” or “Step”

For any part exposed to differential pressure, it is important that the design features a shoulder or step at the low-pressure end (shown on the right side of Figure 1) to ensure the differential pressure does not dislodge the Vespel® CR-6100 during operation.

 

Some radially split multi-stage pumps (BB4 and BB5) pumps feature metal wear rings welded into the pump diffusers with no step or shoulder incorporated in the design. In this case, you can consider modifying the diffusers so that the case wear rings have an “L” shaped profile like the rings below which were used in a hydrocracker charge pump.

Figure 2: “L” Shaped wear ring profile for BB4 or BB5 pump type.

 

Conclusions

Vespel® CR-6100 can help you avoid pump seizure during extreme events like running dry. The temperature limit is 500 F (260 C), allowing it to survive infernal heat waves. The material is not affected by electromagnetic pulses. polar shifts, or solar flares. As an added bonus, Vespel® CR-6100 has an indefinite shelf life, making it an ideal material to stockpile in your underground bunker, and the material is likely to hold its value in the case of hyperinflation.

 

In reality, you don’t have to stockpile the material. Boulden carries a huge inventory of stock sizes in the USA, Europe, and Singapore. You can generally receive whatever material you need in a matter of days.

 

To prepare your pump for whatever the future holds, please contact Boulden with your application details and dimensions. We’ll be happy to walk you through the installation details–assuming we have not been wiped out by an asteroid strike.

Todays Photo

All this talk of disaster is making me hungry. This is some excellent Bun Cha in Vietnam.

 

 

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!

 

 

Measuring Your Pump

Upgrading pumps with composite wear components

Which information is needed in order to upgrade your pump to DuPont™ Vespel® CR-6100?

Review

Using Vespel® CR-6100 wear parts with reduced clearance can help your pumps be more reliable, efficient, and easier to operate. Which measurements and which process data do we need to assemble for the upgrade?

Dimensions Needed for a Quote

Let’s start with the 3 dimensions we need to determine material sizes and availability shown in Figure 1:

  • “R” Outside diameter of the rotor running against the Vespel® CR-6100
  • “B” Inside diameter of the bore the Vespel® CR-6100 will press into
  • “L” Length of the bore
  • Alternative: the O.D., I.D., and Length of the existing parts

If we have those 3 dimensions for each part plus the quantity of each part required, we can provide a quote

Dimensions of Design

Figure 1: Dimensions for designing a Vespel® CR-6100 part

To design parts for fabrication, we will need the dimensions of the mating hardware. While many wear parts have a simple O.D., I.D., and Length profile, some parts have additional features for which we will want the dimensions:

  • Some pump wear rings have profiles like an “L”, “T”, or “Z”. In those situations, we need to know each of the diameters and widths of any of the “shoulders” or “ribs” of the parts
  • Is the pump axially or radially split?
  • Are any of the parts are axially split?
  • For vertical pump shaft bearings, it will be helpful to know if there is any groove profile required-spiral grooves, axial grooves, how many, what diameter, how deep…
  • What is the existing material and clearance of the vertical pump shaft bearings?

Process Conditions

Vespel® CR-6100 works in most process services. It is manufactured from Teflon™ PFA and carbon fibers, so it is chemically resistant to nearly all process chemicals and it has a broad temperature range. There are only two general limitations:

  • Temperature range is cryogenic -300 F (-200 C) to 500 F (260 C)
  • Avoid abrasive slurries, slops, and bottoms services

To design the parts, the pump operating temperature is required in order to determine the correct press fit for the Vespel® CR-6100 parts.

 

Differential Pressure

If the components are going into a high-energy pump, such as a multi-stage horizontal charge pump or boiler feed water pump, we recommend that the patent-pending Boulden PERF-Seal™ design be used on all horizontal multi-stage pumps. The PERF-Seal™ design is fabricated from Vespel® CR-6100 and increases the efficiency gain and rotor damping associated with the upgrade. If the PERF-Seal™ is not used, we will need to know the differential pressure across the components in order to verify that they are designed correctly.

 

Figure 2: PERF-Seal center bushing from a boiler feed water pump

Conclusions

In the ideal situation, you can supply the dimensions of the parts required, the pump cross-sectional drawing, and the API data sheet for the pump. From this information, we can confirm that the service is a good fit for Vespel® CR-6100, quote the material or machined parts required, and make a recommendation on how to install Vespel® CR-6100 into the pump.

Please feel free to contact Boulden with your application details and dimensions. We’ll be happy to provide a budget estimate or a fixed quote depending on the information available. Once you decide to go forward with the upgrade, we have whatever material you need in stock in the USA, Europe, and Singapore.

Todays Photo

Petronas Towers, Kuala Lumpur, Malaysia

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!

 

 

Upgrading Pumps With Composite Wear Components Part: 1

Part 1: Minimize the Risk of Pump Seizure

Welcome to our series on upgrading pumps with composite materials. Over the next few months, we’ll cover the basics of why and how to use composite materials, specifically DuPont™ Vespel® CR-6100, to make your pumps more reliable, efficient, and safe.

Metal Parts Seize

Centrifugal pumps contain contact points between rotating and stationary parts. Most designs use replaceable wear components at these contact points: wear rings, inter-stage rings, throttle bushings, center-stage bushings, vertical pump shaft bearings, throat bushings. In the past, both the rotating and stationary parts would typically be metal.

With metal rotating and stationary components, there is a risk of galling or pump seizure. Galling can cause your pump to stick during assembly in the workshop, during alignment, or when the pump is slow-rolling in the field. This is a nuisance which can cause costly delays, returning the pump to the shop for disassembly, clean-up, re-assembly, and a return to the field. If a pump seizes during full-speed operation due to running dry, low flow, valve failure, bearing failure, shaft breakage, or another off-design scenario, the welding of metal parts together will generally cause the pump to stop abruptly, causing severe pump damage along with the potential for safety and environmental impacts.

 

new boulden

Vertical LPG pump with metal shaft bushings seized, shaft broke, impellers and bowl assemblies destroyed.

Eliminate the Metal-to-Metal Contact Points in Your Pump

At a very basic level, the reason to upgrade the wear components in your pumps to composite materials is because composite materials are completely dissimilar to metal. Due to the totally different material compositions, metal-to-composite contact does not result in seizure like metal-to-metal contact.

So, our first objective when we are upgrading our pump with composite materials is to eliminate the metal-to-metal contact points within the pump. When using Vespel® CR-6100, the rotating parts will typically remain metal and the stationary parts will become Vespel® CR-6100. With this simple change, we now have metal-to-composite contact points in the pump and the risk of seizure is minimized.

Horizontal LPG pump ran dry with Vespel® CR-6100 case rings. No damage to impellers, case, shaft, or bearing housings. Photo: Vespel® CR-6100 wear ring as found during disassembly

Horizontal LPG pump ran dry with Vespel® CR-6100 case rings. No damage to impellers, case, shaft, or bearing housings. Photo: Vespel® CR-6100 wear ring as found during disassembly.

Conclusion

Eliminate the metal-to-metal contact points in your pumps by upgrading the stationary components to Vespel® CR-6100. This simple upgrade will minimize your risk of pump seizure, eliminate nuisance repairs from pumps galling during alignment or slow-roll, and will help mitigate the risks and damage due to off-design operational events including dry-running operation.

Because the risk of pump seizure is minimized, you can now safely reduce the clearance at the wear components, setting up several additional benefits. We’ll talk about reducing the clearance in Part 2.

Until then, if you have had troubles with a pump which galls or seizes, contact Boulden to discuss upgrading the wear parts to Vespel® CR-6100. We have a huge stock of Vespel® CR-6100 standard sizes in the USA, Europe, and Singapore available for immediate delivery to your workshop.

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