What is the Best AODD Pump Diaphragm?

The Next Generation: Internal Piston Diaphragms

While Wilden did not invent the IPD, its engineers have been able to develop a unique IPD design that uses the same hardware as standard full-stroke diaphragms, which means there is no tradeoff in performance when using a Wilden IPD, something that can’t be said for other IPD-diaphragm designs (see illustration below).

Specifically, Wilden has designed new models of IPDs,  which can achieve a traditional stroke length that will optimize flow rates, suction lift and efficiency.

Wilden’s Chem-Fuse Diaphragms deliver an elevated level of pumping performance, which makes them ideal for high- volume chemical and industrial liquid-handling applications. Most significantly, elimination of the potential leak point at the outer piston makes Chem-Fuse diaphragms the best choice when the application involves the transfer of critical, dangerous or hazardous liquids.

Additional features of Chem-Fuse diaphragms include:

• Elimination of outer piston abrasion for longer diaphragm life, especially when pumping abrasive fluids
• Easy cleanability for faster changeovers between product
• Up to 100% increased flow and suction lift compared to other reduced-stroke IPD diaphragms
• Wil-Flex construction, which makes them 50% less expensive than PTFE-laminate diaphragms
• Compatibility with Pro-Flo® SHIFT bolted metal and plastic pump models
• Size availability from 25 mm (1″), 38 mm (1.5″), 51 mm (2″) and 76 mm (3″)
• Temperature ranges from -40oC to 170oC (-40oF to 225oF)
• Availability of high-pressure models for use with Wilden H800 model pumps

Diaphragm Performance Optimization Examples

Talking about the concepts behind the improvements in diaphragm construction and performance is one thing, but real-world examples are another. Since they have been introduced to the market, the Chem-Fuse IPDs have gained rapid acceptance from their users. Here are several examples.

• A U.S.-based paint manufacturer was using 2″ Wilden AODD pumps with standard Wil-Flex diaphragms to move a titanium dioxide (TiO2 ) paint slurry in its manufacturing operation. The Wil-Flex diaphragms were wearing out every three to six months because of the TiO2 slurry’s abrasiveness. However, since switching to Chem-Fuse IPDs, the pumps have been running for more than three years without needing to be replaced, an increased life span of 6 to 12 times the original diaphragms.
• A U.S.-based company that manufactures a polishing compound for glass and plastics – which is twice as abrasive as TiO2 – was using 1″ plastic Wilden AODD pumps for the operation. After experimenting with numerous diaphragms, the company switched to Chem- Fuse IPDs in early 2016 and has not had a diaphragm fail since.
• A U.S.-based glass manufacturer that produces large telescopic lenses for use in aerospace applications uses an abrasive silica to polish the faces of the lenses. To facilitate this polishing process, the customer utilizes Wilden 2″ ductile-iron AODD pumps. After experiencing failures with standard rubber diaphragms, the manufacturer turned to Chem-Fuse IPDs, which provide the flow rates and suction lift that are necessary to successfully perform the silica-pumping process while protecting against harmful leaks.
• A company that develops nutritional ingredients that are used in the production of animal feeds uses approximately 90 Wilden pumps in its manufacturing operation. The pumps were initially equipped with Teflon® diaphragms, but switched to Wil-Flex diaphragms. However, the abrasive nature of the liquids that were being handled was causing premature failure to the Wil-Flex diaphragms. As a solution, all 90 pumps have been converted to Chem-Fuse IPDs and the user has experienced increased diaphragm life, while eliminating any chance that product-to-product cross- contamination will occur.

Over the years, the diaphragms that play such an important role in the operation of AODD pumps have undergone some very meaningful revisions in their designs and materials of construction. The most recent has been the development of integral-piston diaphragms that can eliminate the wear and product-containment concerns that have hampered standard diaphragm models, but do it while producing a stroke length that can optimize flow rates, suction-lift capabilities and efficiency. Wilden has contributed to this “path for the diaphragms of the future” by creating the Chem-Fuse IPDs, which have already begun to leave their mark on many critical liquid-handling applications in the chemical and industrial markets.

Wilden is the global leader in air-operated double-diaphragm (AODD) pumps and a product brand of PSG, a Dover company. This article was written by James Farley, Sr. Director Product Management.