solenoid valves provide a cost effective compact system design
Solenoid Valves are devices that use a solenoid to Control Valve activation. Actuation methods include electric, electro-hydraulic, electro pneumatic, and pneumatic. Unpowered states include normally open and normally closed. In a tandem center solenoid valve, the pressure and tank ports are connected while the service ports are blanked. This allows system unloading while still providing isolation of the service lines. In a float center solenoid valve, the supply pressure port is closed. All others ports are interconnected. This allows the supply to be shut off while enabling the load to move or free wheel with flow available to other services.
Solenoid valves include ball and butterfly valves. Ball valves provide tight shut-off and characterizable control. They have high rangeability due to the design of the regulating element, without the complications of side loads typical of butterfly or globe valves. Butterfly valves control the flow of gas or liquid by means of a disk, which turns on a diametrical axis inside a pipe or by two semicircular plates hinged on a common spindle, which permits flow in only one direction. They are normally used as throttling valves to control flow. Butterfly valves are solenoid valves that offer a rotary stem movement of 90 degrees or less, in a compact design. Unlike ball valves, butterfly valves do not have any pockets in which fluids may become trapped when the valve is closed.
Cartridge valves are solenoid valves that are inserted into manifolds to provide a cost effective compact system design. Pinch valves have a flexible elastomer body that can be pinched closed, cutting off flow, using a mechanism or fluid pressure. Diaphragm valves are similar 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.
Gate or knife valves are solenoid valves in which a flat closure element slides into the flow stream to provide shut-off. Gate valves are usually divided into two types: parallel and wedge-shaped. The parallel gate valve uses a flat disc gate between two parallel seats, upstream and downstream. Knife valves are of this type, but with a sharp edge on the bottom of the gate to shear entrained solids or separate slurries.
Globe valves are solenoid valves with rounded bodies. They are widely used in industry to regulate fluid flow in both on/off and throttling service. Needle valves have a slender, tapered point at the end of the valve stem that is lowered through the seat to restrict or block flow. Fluid flowing through the valve turns 90 degrees and passes through an orifice that is the seat for a rod with a cone shaped tip. These small valves are widely used to accurately regulate the flow of liquids and gases at low flow rates. The fine threading of the stem and the large seat area allow for precise resistance to flow.
