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Saunders® special feature about diaphragm valves

Updated: Jul 11, 2023

Special features of Saunders® diaphragm valves

Since P. K. Saunders invented the original diaphragm valve in 1928, Saunders® has been leading the way in providing world-class fluid handling solutions to a diverse range of critical industries. Saunders® Industrial Diaphragm Valve range encompasses a complete line of manual and linear actuated diaphragm valves. Saunders has overcome most of the weaknesses of diaphragm valves that other brands cannot.

Saunders® solutions 

1. Due to the valve body lining and diaphragm manufacturing process and limitations, it is difficult to produce large valve body linings and large films, so the diaphragm is not suitable for large pipe diameters, but only commonly used at DN≤200mm.

Backed by more than 80 years of experience in polymer technology, Saunders® takes great pride in developing and manufacturing its polymer compounds. It’s Science Inside™, that’s the difference. As a result, the Saunders® plant produces a wide range of high-performance membranes and valve sizes for a wide variety of industrial applications.

2. Diaphragm valve is designed for aseptic production in the pharmaceutical and food industry with a stainless steel body and controlled sulfur concentration, refined PTFE membrane, ensuring the level of sterility for maximum production efficiency.

3. Diaphragm valve is a type of valve that uses a plastic diaphragm with elasticity to regulate the flow of material. This diaphragm has a latch that connects to the push pin. This push handle moves up and down thanks to the valve

Saunders® valve’s stem is not the push pin 

Diaphragm connects to the Compressor via the Threaded or Bayonet style stud depending on the Diaphragm type. The Compressor matches the Valve seat profile to provide uniform Diaphragm clamping pressure across the sealing surface area of the body. The Compressor connects to the Valve Stem which, in the Saunders® design, is protected from the elements by a bonnet/ hand-wheel design and is lubricated permanently for its entire length, maintenance-free service life.

4. One of the benefits of the Diaphragm valve design is that the Operating mechanism is isolated from the process fluid. The spindle and threaded sections are protected from scale, corrosion and solids buildup, unlike other Valve types, which often have those factors jamb their structure and make them difficult to operate in service.

The Saunders® diaphragm is an intricate design and not a simple moulded part. Layers of proprietary blended and calendared (rolled into sheet form) rubber are vulcanized with high-strength woven reinforcement. The Diaphragms are constructed with multiple layers of rubber and fabric reinforcement for optimized flex performance, even in high-cycle applications. Sealing ribs on the diaphragm's wetted face provide enhanced leak-tight sealing capabilities and lower closure torques. Proprietary formulations, uniquely owned by Saunders, deliver the necessary physical properties to provide excellent abrasion and corrosion resistance.

5. When operating diaphragm valves, do not apply excessive force when closing the valve as this can trap the diaphragm in the sealing ring and damage the diaphragm.

This is not an issue with Saunders®, it is with KDV and other brands that you can rip the studs out of the diaphragm but it is not likely the case with Saunders®. Anyone applying too much effort to the valve does not understand its principles and is probably not someone who is going to be reading this document anyway. 

6. The lowest pressure the valve can handle depends on the membrane material and the temperature of the fluid. Also, valve life is influenced by the physical and chemical properties of the fluid. Furthermore, the hydrostatic pressure of the system should not exceed the maximum diaphragm pressure level.

In contrast, the highest pressure is determined by the valve size and the Diaphragm type. Diaphragm valves are limited in their Pressure rating more by Rim Pull Effort than by the materials. If you look back at the original Saunders data, there were all rated for higher pressures than they are these days. At some point, the British Valve Association put a limit on Rim Pull effort (effort required to operate the valve) and as a result, the Diaphragm valve pressure ratings were lowered.

Saunders® equipment and being redefined its brand in the world, Daviteq is proud to be the official distributor of Saunders®/ Crane optimal solution for industrial factory systems in Vietnam. For more information and support product advice, customers can contact us by email at



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