PTFE Diaphragms & Valves for Chemical Transfer Pumps
In chemical processing where aggressive or hazardous conditions are involved, the pumped media can be of a very low lubricity and therefore abrasive. These problems challenge the permeability of the surface and result in potentially harmful vapors or VOCs damaging pump components and leaking to the atmosphere.
Chemical Diaphragm Pumps in Processing Industries
Where chemicals are being manufactured or being brought together in the production of finished products such as paints, adhesives, resins, and coatings pumps are in dedicated hazardous areas. Any leakage either of fluids or vapors in chemical processing cannot be tolerated, thereby placing the greatest importance on diaphragm integrity. Whether used in double diaphragm oil pump or air operated double diaphragm oil pumps (AODD), the diaphragms must be chemically resistant and the pumps must be safe and reliable.
Chemically Resistant Diaphragm Pumps
With almost universal resistance to chemicals and extremely aggressive media such as aromatic or chlorinated hydrocarbons, acids, caustics, ketones and acetates, Saint-Gobain’s Flex Barrier products provide solutions to these challenges in continuous use temperatures of up to 260°C (500°F).
Used either on its own, or as part of rubber backed diaphragms, CHEMFILM® fluoropolymer films provide exceptional barrier properties for diaphragms, enabling them to withstand million to tens of millions of flex cycles – they have been shown to increase flex cycles and lifetime up to 70% higher than regular modified PTFE and reduce vapors permeability by 30% in certain applications - with little to no loss of mechanical function at elevated temperatures for as many as 20,000 service hours.
With specially designed bondable versions available, the CHEMFILM® barrier films can be bonded to the customer’s carrier diaphragm (typically rubber) and subsequently thermoformed and vulcanized, usually in a single operation. Saint-Gobain's films provide low permeability protecting both the rubber backing as well as the bonding between the PTFE and rubber. PTFE films minimize voids and improves overall diaphragm flexibility within the pump system lowering the premature failure rate and increasing overall lifespan. Available as single layer film or laminated composites, Saint-Gobain’s Flex Barrier can be thermoformed by customers to produce a diaphragm to their required size.
Reliability Requirements for Chemical Diaphragm Pumps and Valves
Made from the highest quality virgin Polytetrafluoroethylene (PTFE) resins, CHEMFILM® products have outstanding corrosion resistant properties due to the low permeability of the material and its extremely low moisture absorption characteristics (<0.01%).
PTFE rupture, a major cause of diaphragm premature failure, has been solved by the exceptional flex-life performance of Flex Barrier - with a tensile strength min. values of 3500 psi/25 N/mm², Flex Barriers represent an exceptional resistance to elongation fatigue. This is reinforced by the high elongation at break, or fracture strain, of at least 280% (min. values) and a tensile modulus of 80,000 psi (145 N/mm²)
No sterner test of Flex Barriers’ resistance to chemicals has been on the Ariane 5 space program. Working with the Ariane Group we produced a multi-layer fluoropolymer laminate that met safety and production costs criteria. enabling the rocket to enter space with a more effective fueling system.
Material Selection Guide for Chemical Transfer Pump Diaphragms
|Material||Product Code||Thickness, mm||Key Features||Optional Features|
|PTFE Skived Film Premium||0100||0.025 - 3.0||Outstanding, almost universal chemical resistance||Customization available|
|PTFE Skived Film Modified||0200||0.025 - 3.0||Low permeation and friction||Customization available|
|PTFE Skived PTFE Film Flex Barrier||LP01
0.4 - 1.0
|Excellent crack resistance and flex life in most demanding chemical applications||Customization available|
For all our materials, we offer customization options tailored to suit your needs. Please Contact Us to discuss your requirements or to request a call back from one of our pump diaphragms technical experts.