Diaphram valves, more properly known as diaphragm valves, are inline devices that utilize a membrane to transect a pipe completely or partially in order to regulate the flow of liquid, gaseous, or semi-solid process streams.
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Applications of Diaphram Valves
Many industries use of diaphram valves in their daily operations to monitor and control the flow of such materials as silicones, adhesives, oils, chemicals, water, cleaners, sanitizers, coatings, and fuel. These industries include biopharmaceutical, agriculture, irrigation, plumbing, medical, water treatment, chemical and food processing, pulp and paper, mining, and energy production.
How Diaphram Valves Work
The function and design of a diaphragm valve is relatively simple. The body of the valve is a cylindrical or spherical device that is attached to the necessary piping. This compartment houses the actuating device and stem or rod. Placed directly in front of the rod is the diaphragm. On the opposite side of the pipe is a raised bump. When the compressed air, hydraulic fluids, or manual turning engages the stem, it presses down on the diaphragm, which is stretched to the desired depth. To shut off flow completely, the diaphragm must cover the entire diameter. When the valve is open the stem retracts and the diaphragm returns to its relaxed position, allowing fluids, gases, and particulates to pass freely below.
Types of Diaphram Valves
While a number of different valves are widely available, the use of an elastomeric diaphragm in these particular valves significantly reduces both cost and the risk of leaks. Process valves such as these are capable of starting, stopping, and modifying flow rates and pressures, as well as ensuring the proper flow directionality. These tasks can be performed through the use of automated systems, as with electrical, hydraulic, and pneumatic diaphragm valves. Alternatively, manually operated membrane valves are also widely available. In simplified terms, when the diaphragm is engaged by any of the aforementioned actuating devices, the diaphragm (or membrane) is stretched to the opposite side of the valve. This effectively forms a barrier. The chemical composition of a process flow, as well as the material construction of each diaphragm valve component, should be carefully considered, as incompatible materials can lead to mechanical failure or malfunction as well as product contamination. Compatible valve materials include polypropylene, ethylene, copper, brass, stainless steel, PVC, CPVC, and other durable and chemically resistant materials.
Points to Consider When Selecting a Diaphram Valve
In addition to the material construct of a diaphragm valve, it is important to consider media type, temperature, and pressure ratings, frequency of operation, diameter and other dimensions, required end connections, and process stream velocity. Diaphragm valve manufacturers and retailers can provide helpful insight and should be consulted before purchasing or installing such a device if any uncertainty persists. Proper installation of a suitable valve provides a reliable and leak-proof flow control device for any plumbing or material transport operation.