Solenoid Valves

About Solenoid Valves and Solenoid Valve Manufacturers Including: 3 Way Solenoid Valves, 12 Volt Solenoid Valve, Air Solenoids, Air Valves, Gas Solenoid Valves, Miniature Solenoid Valves, Plastic Solenoid Valves, Pneumatic Valves, High Pressure Solenoid Valves, Proportional Solenoid Valves & Solenoid Water Valves.

Solenoid valves are one of the most common flow control valves in commercial, industrial, and home tools and appliances. Ice cube makers, refrigerators and dishwashers are a few home appliances that operate with solenoid water valves. Proportional solenoid valves, air valves and air solenoids are manufactured for air and gas flow regulation and are most often pneumatic. A wide range of industries use pneumatic and air valves to power industrial tools and motors, for heating and cooling, electronic, medical and dental equipment. Solenoid hydraulic and water valves are also used in oil tooling, aerospace, fuel systems and automotive industries. Hydraulic valves regulate flow of fluid or water and include proportional solenoid valves and solenoid water valves. Solenoid valves provide excellent solutions to regulating fluid and air flow. The solenoid valve is powered by natural pressure and electromagnetic force; having fewer moving parts is considered good design, since moving parts require maintenance. Solenoid valves are also easily operated by remote devices that activate the solenoid coil, making solenoid valves extremely useful for operating potentially dangerous machinery or inaccessible lines. Able to be 2-way 4-way or 3-way valves, a 3 way solenoid valve is a type of flow control valve that has three connections and two orifices. In addition, there are 3v, 6v and 24 volt solenoid valves; however, 12 volt solenoid valves are the standard. Constructed from plastic materials, plastic solenoid valves are primarily used in applications that require corrosion or chemical resistance. Miniature solenoid valves are most commonly used in medical applications such as gas analyzers, biotechnology equipment, and portable medical devices since they offer excellent control of acids, analytical reagents and bases.

Solenoid valves control the flow of gases or liquids through tubes, as regular valves do, but unlike other valves, solenoid valves can be controlled remotely. Operated electromechanically by a solenoid, which is a magnetized coil activated by electrical charges, solenoid valves control the flow of gases or liquids precisely through targeted electrical charges, sensor cue or by hysteresis (device memory). In many valves - such as pneumatic and diaphragm valves - liquid or gas pressure changes help to close and activate the valve. In a normally closed (NC) valve, a plunging pin or rod within the valve is held blocking the passage of air or fluid by a solenoid coil; the air or fluid pressure coming into the valve helps keep the valve shut as long as the pin blocks the passage. In order for gas or fluid to flow through the valve, an electromagnetic charge is run through the solenoid coil, which becomes active and lifts the plunger out of the passage and allows flow through the entire valve. Normally open (NO) valves are the opposite; they remain open until the solenoid is activated and pushes down the plunger, blocking flow and creating pressure to keep the valve closed.

Solenoid valve manufacturers make two general types of valves: direct-acting and pilot-operated. Direct-acting solenoid valves have a plunger that is in direct contact with the in-flow opening in the valve body, or orifice. This plunger is used to open and close the orifice, which permits or hinders flow. The pilot-operated solenoid valve, which is actually a combination of a pneumatic or hydraulic valve and a smaller solenoid valve, works with a diaphragm rather than a plunger, using differential pressure to control the flow of gases or fluids. In pilot-operated valves, often the same as diaphragm valves, there is a solenoid-operated vent which is opened to allow the pressure to equalize, permitting fluids or gases to flow through the diaphragm in the valve's larger chamber. Both direct-acting and pilot-operated valves use solenoid coils to move parts and create flow. Direct-acting solenoid valves need more power to be activated initially, but they can remain open (or closed, in a NC valve) with relatively little power and respond much more quickly to activation than pilot-operated valves.

A distinction must also be made between pneumatic valves and hydraulic valves. Pneumatic valves utilize compressed air to regulate flow, while hydraulic valves use fluids such as water or oil, which compress far less than gases; thus pneumatic valves can offer highly pressurized gas flow, while most hydraulic valves regulate fluid flow at lower pressures. Hydraulic valves can, however, provide powerful force and are frequently used with water or petro-based oil to move heavy equipment or engine parts at high speeds. Pneumatic power is considered cleaner and lower maintenance than hydraulic power, due to the absence of degrading fluids which produce waste and must be maintained. Both pneumatic and hydraulic valves can be activated or piloted by solenoids.

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Solenoid Valve Types

• 2-Way solenoid valves are used for hydraulic and pneumatic applications. 2-Way solenoid valves have two ports called pressure and service ports.
  
• 3-Way solenoid valves are for hydraulic and pneumatic applications. 3-Way solenoid valves have three ports, one being the pressure port, one the tank and the last, the service port.
• 12 volt solenoid valves are the standard amount of voltages supplied by the direct current (DC) power source.
• Air solenoids are control air flow in a pneumatic system.
• Air valves regulate the release of air.
• Gas solenoid valves are one of the most common flow control valves that that handle and control the flow of gaseous media.
• Hydraulic solenoid valves use fluid pressure and are ported through the return line to the reservoir.
  
• Miniature solenoid valves fit easily into a small area and also measure or dispense small amounts of material. Mini solenoid valves are particularly useful in medical applications.
  
• Plastic solenoid valves are primarily used in applications that involve corrosion or chemicals.
  
• Pneumatic solenoid valves are similar to the hydraulic version in that they both use pressure. However, the return port of a pneumatic valve, which uses air, is exhausted to the atmosphere.
• High Pressure solenoids are solenoid valves that control the flow of fluids or gases in high pressure applications.
• Proportional solenoid valves have direct-acting control valves with linear characteristics. Proportional solenoid valves control accuracy, hysteresis and repeatability within close tolerances.
  
• Rotary solenoids valves have three bearing balls that ride on an inclined plane and turn linear motion into rotary motion. The magnetic arrangement permits direct rotational motion.
• Solenoid water valves are electrical devices that control water flow.

Solenoid Valve Terms

Analog Position Sensor - Position sensor whose voltage output differs through various values.

Bubble-Tight Sealing - A circumstance in which there is no leakage of air from between the internal sealed ports of the valve, whether in the energized position or not, in a five second time period. Soap bubbles are used to detect leakage.

Closed State - A situation in which the tubing is pinched in the valve.

Coil Voltage - The maximum voltage to which the coil must be energized for the valve to achieve its highest specified capacity.

Continuous Duty - Energizing a solenoid valve at a constant level of power for its entire on-time.

Current Drain - The quantity of current in amperes flowing through a solenoid valve coil when it is energized.

Cycle - The normal opening and closing of a valve.

Cycle Rate - The measure of how many times a valve is able to open and close within a set period of time.

Duty Cycle - Proportion of time that the solenoid receives power.

Flow Control - A feature that allows for the manual reducing or controlling of flow.

Flux Plate - Magnetic steel plate that helps transmit magnetic flux in the magnetic circuit of a solenoid valve from the enclosure to the sleeve construction. A flux plate is necessary on valves with a body construction consisting of a non-metallic body.

Frequency Response - Changes with the output variable in steady-state conditions, caused by a sinusoidal input variable.

Gain - Association of input to output or the sensitivity of a device.

Hysteresis - The variation between up-scale and down-scale outcomes in equipment response, when exposed to the same input from the opposite direction.

Normally Closed - A term that refers to a valve that is closed when unenergized.

Normally Open - A term that refers to a valve that is open when unenergized.

Open Loop - A system in which direct feedback is not supplied to gauge the response.

Position Sensing - Employing electronic sensors to watch the position of the valve and provide electronic feedback.

Pulse and Hold - Increases function of solenoid valves by reducing power consumption and heat generation. The valve is opened and held open at decreased power.

Pulse Width Modulation (PWM) - A technique that utilizes a modulated wave function to control analog devices.

Repeatability - The ability of the equipment to generate consistent results on successive tests.

Stroke - The space the plunger covers during a state change.