Intro4u2u

Single component diaphragm valves are designed to provide a precise fluid supply depending on the application. The dispensed output can be a bead, dot or fill. Material pressure upon the valve forces the diaphragm to allow material through the fluid body and out the dispensing tip. Applying air pressure to the top of the diaphragm forms a seal, thus, closing off the valve. Diaphragm valves generally have a low number of moving parts and are often used to dispense low viscosity fluids including cyanoacrylates (superglue).

Diaphragm valves are related to pinch valves, but use an elastomeric diaphragm, instead of an elastomeric liner in the valve body, to separate the flow stream from the closure element.  Instead of pinching the liner closed to provide shut-off, the diaphragm is pushed into contact with the bottom of the valve body to provide shut-off.  Diaphragm valves are excellent for controlling the flow of fluids containing suspended solids and offer the flexibility of being installed in any position.  These types of valves have found widespread use in the pharmaceutical, food processing, and water treatment industries.

Manual diaphragm valves are ideal for flow control by offering a variable and precise opening for controlling pressure drop through the valve.  Actuated varieties can offer features as adjustable opening, positioners for precise flow control, and electric relay of valve position.

The advantages provided by diaphragm valves are many.  They are extremely clean, and can form a nearly leak-proof seal for tight shut-off.  The diaphragm design provides for easy maintenance and repair as it can be replaced without disturbing the piping line.  However, they are limited to moderate temperatures (-60 to 450°F) and pressure service (approximately 300 psi) by the mechanical properties of most common diaphragm materials. They cannot be used in multi-turn operations.

Diaphragm valves are available in two basic forms: weir type and straight through types.

The weir design is best for general use applications or for tough corrosive and abrasive services.  The straight through type can be used in situations where the flow direction changes within the system.  They are excellent for use with sludge, slurries and other viscous fluids.  Both styles provide a streamlined path for fluid flow that yields minimal pressure drop across the valve.

Single component diaphragm valves offer a number of specific advantages when working with viscous fluids.  First, their single part construction lacks specific weak points that multiple part devices have.  Therefore, they can accommodate the greater pressures and stresses that accompany high viscosity products.  Additionally, these diaphragm valves have fewer seam locations that could allow external air ingress that would cause aerobically curable products to harden. The result of this would be product backing up in the system and eventual seizure, leading to production downtime and extensive cleaning.

Related keywords: bronze valve, toro sprinkler valve, reed valve, component engineering, valve lapping, grinding valve, timing valve, component case, tufline valve, com component, lapping valve, component extrusion, quick exhaust valve, telescoping valve, lucifer valve, inert valve, union valve, habonim valve, thermoplastic valve, diaphragm valve manufacturer