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How do Pilot Operated and Direct Operated Solenoid Valves Work?

On February 22, 2017, in Electrode Products, Solenoid, by Lambert

What are Solenoid Valves?

A solenoid valve is an electro-mechanical valve that is used to control the flow of liquid or gas. The solenoid starts by converting an electrical signal into a mechanical movement. The signal is then sent to a coil and the movement then occurs inside of the valve. Solenoid valves are usually be described as pilot operated or direct operated/acting.

 

Pilot Operated Solenoid Valves

2 way pilot operated solenoid valves have two chambers separated by a diaphragm. The upper chamber is connected to upstream through a pilot hole in either the cover or diaphragm. The media exerts a pressure that acts on the upper side of the diaphragm and keeps the valve closed. When the coil is charged the core lifts off the orifice seat allowing the operating chamber to de-pressurize. The thrust of the upstream pressure under the diaphragm continues, lifting the diaphragm and opening the valve.

 

Pilot operated solenoid valves only operate with a suitable upstream pressure differential and do not operate at zero pressure. Also a minimum pressure differential across the valve is required to keep them open or closed. Pilot operated solenoid valves can provide high flow rates at high pressures with lower power consumption.

 

Direct Acting Solenoid Valves

Direct acting solenoid valves do not use a diaphragm, their seal is part of the moving core. Two way NC direct acting solenoid valves have a spring that holds the core against the seal. When the coil is charged the spring is overcome and the seal is lifted from the orifice seat thus opening the valve and allowing the media to pass through the valve.

 

Two way NO direct acting solenoid valves have a fixed core which usually in the bottom section of the armature tube. The armature is located in the upper part of the valve. A stem passes through the fixed core and is coupled to the seal. This is held off the seal by means of a spring and makes a seal when the coil is energized, thus closing the valve.

 

Three way direct acting solenoid valves work in almost the same way as a two way direct acting solenoid valve. The fixed core has an exhaust orifice running through it. The plunger has an upper seal and lower seal allowing flow to or from either the body seat or exhaust.

 

Direct acting solenoid valves are used when there is no line pressure applied. Typical applications would include a cleaning line when a pump supplies bursts of water through the line. A direct operated solenoid valve would remain closed, even when no pressure is being applied (i.e. in between the busts of water). This is in contrast to a pilot operated valve, which requires some pressure for the valve to stay closed.

 

Excellent Solenoid Valve Manufacturer in Taiwan

SHAKO is one of leading and the largest professional pneumatic solenoid valve manufacturers in Taiwan. With rich experiences and in-deep knowledge, we are able to provide pneumatic solenoid valve products with excellent high quality & rapid service for various industries. If you need more information about solenoid valve series, welcome to visit the website of SHAKO.

 

 

Article Source: http://www.bmengineering.co.uk/news/solenoid-valves/How-do-pilot-operated-and-direct-operated-solenoid-valves-work

 

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What Is a Pneumatic Solenoid Valve?

On November 3, 2016, in Solenoid, by Lambert

A pneumatic solenoid valve is a type of standard electro-mechanical solenoid that, when activated by electrical power, opens a valve under positive or negative air pressure. In standard industrial applications, they have been used for many years as a type of on/off switch for pneumatically powered systems such as with air-powered drills. They have also been commonly employed in fluid control systems such as for releasing hot and cold water into a washing tub in an automatic washing machine, or for outdoor lawn sprinkler systems.

 

The pneumatic solenoid valve differs from the traditional solenoid in that the actuator controls a valve that is under some level of pressure. It can either function to release pressure and allow gas or liquid to flow when electrical current is applied, or the pressure itself can activate the valve in reverse and create an electrical signal that is channeled to a monitoring station.

 

Some pneumatic valve assemblies are also small control units that act as triggers for larger solenoids, and together these types of pneumatic solenoid valve designs are often referred to as a pilot valve or as a compressed air pilot valve. Pilot valves can be stackable, meaning that they can be arrayed in series on a pipeline or other fluid or gas flow assembly so that pressure and flow can be channeled at key points in an industrial process. A single pneumatic solenoid valve that is installed as a pilot valve also often has a manual level of actuator control. This means that the solenoid function of the unit, where the actuator opens and closes the valve, can be controlled manually by pushing a button or moving a mechanical arm. In more sophisticated industrial systems, however, the pilot valve unit is electrically controlled through a series of programmable settings for running power to the solenoid when needed to open or close the valve.

 

In automated industrial systems where large amounts of inaccessible pipeline exist that must be controlled remotely, pneumatic solenoid valve systems are often chosen, as they can be operated by ambient pressure that builds up in the system itself and they don’t require external power. This allows them to act as a type of safety valve to release pressure when needed, and, in the process, the mechanical motion of the pressure release can activate the electro-mechanical feature of the solenoid so that a brief electrical signal is transmitted to a control station to indicate that the valve state has changed. They also serve a reverse function where they can be opened or closed from the control station if an operator determines that a system is not performing properly.

 

Solenoid valve parts can range from very small units for rapid, micro-control systems, where they have a 0.4-inch (10-millimeter) diameter and can be run on low-level direct current (DC) voltages of 12 volts. High-power industrial level valves at the opposite end of the spectrum are made of strengthened steel alloys. They can handle pressures of up to 4,500 pounds per square inch (316 kilograms per centimeter squared) and temperatures as high as 1,200° Fahrenheit (649° Celsius).

 

SHAKO is leading and the largest professional pneumatic solenoid valve manufacturer. Our solenoid valves are available in 6VDC, 12VDC, 24VDC and 110/220VAC. If you need more details about solenoid valve series, welcome to visit our website and feel free to contact us!

 

Article Source: http://www.wisegeek.com/what-is-a-pneumatic-solenoid-valve.htm

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Solenoid Valves – What Should We Know About Them?

On August 26, 2016, in Solenoid, by Lambert

Have you ever used an industrial air hammer? Have you checked on your automotive starter system at one point or another? Have you ever seen an electric bell assembly? If you answer yes to any of these questions, then you probably know what a solenoid valve is.

 

Solenoid valves are electromechanical valves that are controlled by stopping or running an electrical current through a solenoid, in order to change the state of the valve. A solenoid is a coil of wire that is magnetized when electricity runs through it. The solenoid valve makes use of this solenoid in order to activate a valve, thus controlling water flow, airflow and other things with electricity. Basically, there are three types of solenoid valves: the general-purpose type, low-pressure steam type and the high pressure steam type.

 

Solenoid valves are composed of several parts such as the solenoid coil, electrical connector, bonnet nut, seal cartridge, O-rings, end connector, body and union nut. All these components are critical to the overall performance of solenoid valves. If any malfunction, it will affect the entire operation of the automotive starter system, as well as the industrial air hammer and the electric bell assembly. That is why this should always be maintained and regularly checked in order to keep the solenoid valves functioning at their best.

 

But just like any other parts of the starter system, air hammer and electric bell, the solenoid valve can get damaged after a period of time. Thus, a replacement solenoid valve will be needed. It’s a good thing that many dealers offer quality solenoid valves at affordable prices. When selecting a solenoid valve, be sure to consider the valve type, aperture size, pressure rating, coil voltage and type of connection to each port.

 

Summary, solenoid valves are an efficient method of converting electrical signals into pneumatic functions. Applying electricity to the solenoid quickly directs air through the valve and into the circuit.

 

SHAKO is leading and the largest professional pneumatic solenoid valve manufacturer. With rich experiences and in-deep knowledge, we are able to provide pneumatic solenoid valve products with excellent high quality & rapid service for various industries. Now our solenoid valves are available in 6VDC, 12VDC, 24VDC and 110/220VAC. If you need more details about pneumatic solenoid valve series, welcome to visit our website and feel free to contact us!

 

 

Article Source: http://EzineArticles.com/253875