Performance Plastics Improves Compressor Valve Performance With Poppets Made From VICTREX® PEEKPolymer

Manufacturers of check valves and pressure relief valves for hydraulic and pneumatic compressors are constantly looking for ways to improve the performance of their products. Valve performance, more than any other component, determines compressor efficiency.

To achieve reduction in fluid leakage, noise and cost, and extended valve life, Performance Plastics (PPL), recommends replacing the metal poppets with poppets made of VICTREX® PEEK™ polymer, a high performance thermoplastic. Experience has shown that converting to a poppet made from VICTREX PEEK polymer provides tremendous improvements in productivity.

ALLOWS WIDER OPERATING RANGE

One of the major benefits of using VICTREX PEEK polymer   is that it allows the valves to operate in high and low pressure applications. It increases the number of applications in which valves and compressors can be used.

SUPERIOR IMPACT RESISTANCE

VICTREX PEEK POLYMER —

Ideal Replacement for Metal Poppets

Metal poppets have always posed a number of challenges. They can be difficult and costly to machine and the sealing surface can be inconsistent due to difficulties in machining defect-free seat surfaces.

As a replacement for metal, VICTREX PEEK high performance polymer is an engineering solution due to its outstanding combination of properties. Substituting plastic for metal maintains strength while improving corrosion resistance, reducing weight, and allowing for greater design flexibility.

Another benefit of using VICTREX PEEK polymer is its superior impact resistance. According to Performance Plastics, one of the primary reasons why valves fail are the fissures brought on by repeated impact pressure. PPL has had applications where VICTREX PEEK polymer has passed two million impact cycles and another where it has passed 20 million impact cycles.

BETTER SEALING AND WEAR RESISTANCE

Because VICTREX PEEK polymer is compliant and can conform to the mating seat surface, it provides better sealing performance and less leakage than metal poppets. It also offers excellent wear resistance and improved wear conditions on the mating seat surface. Wear and damage to the mating seat surface is a big issue with metal poppets and re-work of pumps and valve assemblies is both costly and time consuming on the production line.

PROPERTIES OF VICTREX PEEK POLYMER

  • High Temperature Resistance — Can withstand continuous operating temperatures of up to 260°C (500°F). Also maintains short-term mechanical properties at temperatures approaching its melting point of 340°C (644°F).
  • Wear Resistance — Outstanding wear resistance over wide ranges of pressure, velocity, temperature and counterfacial
  • Mechanical Properties — Excellent strength, stiffness and long-term properties, such as creep and fatigue, retained over a wide range of temperatures and
  • Chemical Resistance — Exhibits outstanding resistance to a wide range of chemical and corrosive environments, even at elevated temperatures up to 200°C (392°F).
  • Hydrolysis Resistance — Retains high levels of mechanical properties and dimensional stability when continuously operating in water, brine or steam at elevated temperatures and
  • Dimensional Stability — Remarkably stable, resisting changes to its properties due to temperature, moisture, chemical attack or physical

METAL REPLACEMENT APPLICATIONS

Metal to plastic conversions and metal part replacement applications are areas of expertise at Performance Plastics. Because of its superb all-around properties, Performance Plastics has used VICTREX PEEK polymer successfully in many metal replacement applications including:

  • A poppet made with VICTREX PEEK polymer replaced a two-piece metal assembly, resulting in a significant cost reduction. It also improved initial product quality and reduced customer valve rework from 200 units per month to less than
  • Poppets made with VICTREX PEEK polymer provided more sensitivity than the metal poppets, resulting in more consistent pressure relief actuation performance. The plastic poppets also provided a lower noise level than the metal

SUMMARY

Performance Plastics is confident that their experience and proven track record in the high performance area can greatly benefit customers by solving some of their most difficult applications.

Victrex is an innovative leading manufacturer of high performance polyketones, including VICTREX® PEEK™ polymer, VICOTE® Coatings and APTIV™ film.

These materials are used in a variety of markets and offer an exceptional combination of properties to help processors and end users reach new levels of cost savings, quality and performance. All Victrex material production comes under Victrex’s ISO 9001 quality registration.

Victrex USA, Inc.

300 Conshohocken State Road Suite 120

West Conshohocken, PA 19428 USA

Tel: + (1) 800-VICTREX Tel: + (1) 484-342-6001

Fax: + (1) 484-342-6002

Email: [email protected] www.victrex.com

Performance Plastics, Ltd., is one of the pioneer molders specializing in injection molding high performance plastics, and other high performance resins. The company develops innovative, cost effective manufacturing solutions for applications that require highly engineered plastics, sophisticated part geometry, tight tolerances, and technical expertise.

Performance Plastics, Ltd.

4435 Brownway Avenue

Cincinnati, OH 45209

USA Tel: + (1) 513 321-8404

Fax: + (1) 513 321-0288

Email: [email protected] www.performanceplastics.com

VICTREX PLC BELIEVES THAT THE INFORMATION CONTAINED IN THIS BROCHURE IS AN ACCURATE DESCRIPTION OF THE TYPICAL CHARACTERISTICS AND/OR USES OF THE PRODUCT OR PRODUCTS, BUT IT IS THE CUSTOMER’S RESPONSIBILITY TO THOROUGHLY TEST THE PRODUCT IN EACH SPECIFIC APPLICATION TO DETERMINE ITS PERFORMANCE, EFFICACY AND SAFETY FOR EACH END-USE PRODUCT, DEVICE OR       OTHER APPLICATION. SUGGESTIONS OF USES SHOULD NOT BE TAKEN AS INDUCEMENTS TO INFRINGE  ANY  PARTICULAR  PATENT.  THE  INFORMATION  AND  DATA  CONTAINED  HEREIN  ARE  BASED  ON  INFORMATION WE BELIEVE RELIABLE. MENTION OF A PRODUCT IN THIS DOCUMENTATION IS NOT A GUARANTEE OF AVAILABILITY. VICTREX PLC RESERVES THE RIGHT TO MODIFY PRODUCTS, SPECIFICATIONS AND/OR PACKAGING AS PART OF A CONTINUOUS PROGRAM OF PRODUCT DEVELOPMENT.

VICTREX PLC MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, A WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE OR OF INTELLECTUAL PROPERTY NON-INFRINGEMENT, INCLUDING, BUT NOT LIMITED TO PATENT NON-INFRINGEMENT, WHICH ARE EXPRESSLY  DISCLAIMED,  WHETHER EXPRESS OR IMPLIED, IN FACT OR BY LAW. FURTHER, VICTREX PLC  MAKES  NO  WARRANTY  TO  YOUR  CUSTOMERS  OR  AGENTS,  AND  HAS  NOT  AUTHORIZED ANYONE TO MAKE  ANY  REPRESENTATION  OR  WARRANTY  OTHER  THAN  AS  PROVIDED  ABOVE.  VICTREX  PLC  SHALL  IN  NO  EVENT  BE  LIABLE  FOR  ANY GENERAL, INDIRECT, SPECIAL, CONSEQUENTIAL, PUNITIVE, INCIDENTAL OR SIMILAR DAMAGES, INCLUDING WITHOUT LIMITATION, DAMAGES FOR HARM TO

BUSINESS, LOST PROFITS OR LOST SAVINGS, EVEN IF VICTREX HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, REGARDLESS OF THE FORM OF ACTION.

VICTREX® is a registered trademark of Victrex Manufacturing Limited. PEEK™, PEEK-HT™ and APTIV™ are trademarks of Victrex plc. VICOTE® is a registered trademark of Victrex plc.

 

Proprietary Tool Design Software Contributes To Precise Sealing Surface

  • Market: Oil & Gas
  • Project Requirement: Produce an “out-of-mold” net shape fiber reinforced PEEK seal holding dimensional tolerances of .0003 inches.

Overview

Mating parts providing a fluid or gas seal are critical components in most mechanical systems. We commonly think of them in valves and connector assemblies, but they are also found in pressure vessels, compressors, pumps, motors, engines, transmissions, and almost all mechanical power trains. Seals, especially those that mate to moving parts, have a demanding set of quality requirements. Each application has its own specific needs, but all seals are characterized by tight dimensional tolerances and excellent surface finish.

 

compressor valve plate with thermoplastic seals

Dresser-Rand is among the largest global suppliers of custom-engineered rotating equipment solutions for long-life, critical applications in the oil, gas, chemical, petrochemical, process, power, military, and other industries worldwide.  Their industry leading Magnum™ valves are used in all brands of reciprocating compressors, where they are known for operating at high compressor speeds and pressure differentials. The product contains 30 to 100 valve elements manufactured from a fiber reinforced PEEK thermoplastic, providing the high strength and low inertia necessary for reliability at high operating speeds.

 

Challenge

Dresser-Rand engineers wanted to improve the usable life and leakage profile of their Magnum valve without absorbing any increase in component cost.  The sealing surface specifications were tightened to 0.0005 inches (12.7 µ) which was key to accomplishing the performance improvements.

thermoplastic sealing valve

Dresser-Rand’s then current supplier of this component was unable to meet the more stringent sealing surface dimensional tolerances “out of the mold” necessitating a finish machining operation to bring the part into tolerance.  However, machining the sealing surface removed the resin-rich surface of the part creating micro-cracks in the surface and exposing reinforcing fibers. Both of these unavoidable consequences of machining negatively impacted component performance, useful life and cost. While it’s never easy to get “something for nothing”, Dresser-Rand knew the right people to talk to, the injection molding thermoplastic experts at Performance Plastics, LLC (PPL).

Solution

Performance Plastics knew eliminating the machining operation would improve strength, reduce trapped impurities, and lower manufacturing cost.  Thus, PPL’s engineering team focused on producing a “true net shape” part directly out of the mold.   Key to accomplishing the customers goals involved leveraging the Company’s proprietary, iterative tool design process.  It required making a 3D CT scan of preliminary molded parts measuring, in this case, approximately 1 million critical part dimensions.  This analysis identified minute distortions.  Utilizing internally developed proprietary software, PPL integrated the CT scan data with CAD/CAM software to make exacting mold modifications eliminating the out of tolerance conditions.  This process contributed to producing a best in class “out-of-mold” conforming part.

The manufacturing process also had to be optimized to produce the desired performance results.  Although the material posed molding challenges, PPL decided to direct gate the part at the top to ensure symmetry of material flow throughout the cavity, critical in achieving roundness to the sealing surface.

Results

The results of development program surprised everyone. PPL achieved “out of mold” net shape parts with a seal surface capable of meeting sealing ranges of 100 psi to 3,000 psi, with no porosity and consistently meeting dimensional tolerances of 0.0003 inches, or 7.62 µ. Eliminating the need for subsequent finish machining dropped the leakage rate for the valve by 50%, from 1.0 scfm to 0.5 scfm. At the same time, Dresser-Rand reported a doubling of estimated lifetime from 10M to 20M cycles between valve element replacement. Lastly, PPL’s direct gating approach improved material efficiency, by eliminating the sprue and runner system, resulting in a lower price per part.  Dresser-Rand’s customers benefitted from improved performance, increased service life and lower maintenance costs.

For more information about our net shape molding process please contact us.

PPL Races To Solution With Thermoplastic Gear

  • Market: Automotive
  • Project Requirement:  Develop a longer lived, more efficeint drop in replacement for a metal component
  • Project Requirement:  Develop a material with a low coefficient of friction not needing lubricating fluids

Overview

Metals have been the first choice of design engineers for almost three centuries. Developments in highly engineered thermoplastics materials are challenging that dominance. The aerospace and automotive industries have led the charge in this dramatic changeover, initially driven by the need to reduce weight to gain fuel efficiency. Advanced thermoplastic and thermoset systems, including fiber reinforced compositions, are now finding their way into almost every industry.

Some of the benefits arising from metal to plastic conversion are:

  • Reduced part weight and inertia;
  • Net shape (or near net shape) manufacturing, improving material efficiency;
  • Simplified manufacturing processes, with higher repeatability and less scrap;
  • Higher tensile strength with proper part design;
  • Increased part lifetime in corrosive and/or abrasive environments;
  • Greater conformability, providing improved sealing characteristics;
  • Increased lubricity;
  • Greater design flexibility.

Challenge

Race car engineers are always looking for a performance edge with their drive trains. Keeping power output up at maximum level is critical racing success. So when engine mechanics noticed their bronze distributor gear showed noticeable wear by race end, they knew vehicle performance was significantly degraded. The key question was whether or not material substitution could provide them with a longer lasting, higher performing gear.

Fortunately, the designers turned to Performance Plastics, LLC (PPL) for help. Working with Victrex plc, a supplier of high performance thermoplastic polymers, PPL developed an injection molded replacement for the conventional bronze alloy gear. As with most metal to plastic conversions, the first and most critical step is material selection. In this application, the part had to maintain structural rigidity at 120°C (250°F) operating temperatures while being subjected to oil and gasoline vapors.

Solution

PPL teamed with Victrex® technical development engineers to create a custom resin able to survive the high under hood operating temperatures and the abrasion from material to material contact.  Our collective efforts resulted in a unique carbon fiber filled PEEK compound embedded with additives obviating the need for additional lubricants.  PPL injection molds gear blanks to near net shape which are then finished by machining the gear teeth to the desired involute shape.  The injected molded PEEK gear is capable of maintaining a high level of its physical properties while operating close to its melt temperature of 343°C (645°F), well in excess of the requirement.

Results

The new gears were tested in a number of cars before being used in actual races. The gears were examined for surface cracks, chemical attack, distortion and abrasion. Initial testing showed no detectable wear in over twenty-four hours of racing. Additionally, the new gears provided an 81% reduction in part mass and inertia, helping to deliver faster throttle response and more horsepower to the drive wheels. After multiple years on the racing circuit, a single gear is now being used for an entire season, as opposed to being replaced after every race.

For more information about metal to plastic conversion please contact us.