W. L. Gore & Associates, Newark, Del., has introduced One-Up pump diaphragms suitable for use with most chemicals and at elevated temperatures and pressures.
Thanks to a proprietary polytetrafluoroethylene (PTFE) on the wetted side, they last significantly longer than other conventional PTFE diaphragms, claims Gore. “These diaphragms provide a dramatic improvement in service life and are considerably stronger, with greater flex life.” In general service pumps, the diaphragms’ long life and versatility will reduce both maintenance and operating costs — or your money back, says the company.
Figure 2. Proprietary bonding process between the PTFE and the elastomer overcomes traditional problems with both leaching and delamination. Source: Garlock Sealing Technologies.
Garlock has launched the Gylon Style 3545 seal. Made of pure PTFE, it suits media such as strong caustics, strong acids, hydrocarbons, chlorine, and cryogenic fluids as well as glass-lined equipment, plastic piping and low bolt-load applications. Its highly compressible outer layers seal under low bolt load, making the seals appropriate for many non-metallic flanges. Compressible layers conform to surface irregularities, especially on warped, pitted or scratched flanges, while a rigid PTFE core reduces the cold flow and creep normally associated with conventional PTFE gaskets. The soft PTFE can be cut easily from larger sheets, which reduces inventory costs and expensive downtime, while the rigid PTFE core facilitates installation, especially on large diameter flanges and in hard-to-reach areas.
Garlock also offers the Stress Saver 370 for use, e.g., with non-metallic flanges It features raised molded-in sealing rings that seal with 75% less surface area. The pure PTFE sealing surface resists a host of chemicals; a proprietary process is used to bond the PTFE to the elastomer, so that it won’t leach or delaminate (Figure 2).
For the chemical industry, the challenge clearly is to use new technologies in a way that satisfies the demands of both the regulators and the shareholders.