Solenoid Valves

A Solenoid Valve is an electromechanical component, for use with hydraulic or pneumatic applications, consisting of two (2) sections:

The Solenoid converts electrical energy into magnetic energy which, in turn, opens or closes the valve mechanically. Simply put, an electrical current allows the solenoid to magnetically energize the valve allowing it to open or close, thereby regulating and directing the flow of a specific medium.

The internal components of a pressure vessel vary by manufacturer. The majority of Parker Hannifin Corporation solenoid valves utilize a “plunger-type” mechanism which is electromagnetically actuated, direct operating with resilient inserts that seal upon the orifice. Valves are available from sub miniature low flow to large orifice high flow and for varied usage including explosion proof, vacuum and submersible.

The seals used in a solenoid valve are dependent upon the media. Standard type gases and liquids, such as oil or water, will use a Buna N compound rubber. More acidic based liquids may require specialized rubber seals. Higher temperatures may require a Viton or similar rubber compound. Housing options also play a key role in providing a safe environment for the system and its’ Operator.

The term Solenoid refers to a loop of wire, often wrapped around a metallic core, which produces a magnetic field when an electric current is passed through it.

A Valve is a device that regulates and directs the flow of a specific medium, i.e., gases or liquids by opening, closing, or partially obstructing various passageways. Normally Open and Normally Closed valves refer to the "default" valve state that results when electrical power or other control methods are removed. Such valve states are usually selected by a consideration of system safety during a power failure.

Solenoid valves are the most frequently used control elements in fluidics and are used in a variety of applications that include fluid power, pneumatic and hydraulic systems. Their tasks are to shut off, release, dose, distribute or mix fluids. Solenoids offer fast and safe switching, high reliability, long service life, good medium compatibility of the materials used, low control power and compact design.

Solenoid valves are used to control the flow of a variety of liquids and gases such as steam, water, air, nitrous, and oil. They are essential components in equipment used in the preparation and presentation of food products. They are also used in beverage dispensing equipment, commercial water coolers and draining devices incorporated into restaurant and cafeteria operations.

Solenoid valves are found in many of the sub-systems used to assist in the control of a variety of vehicles. Solenoid valves are used on off-highway construction equipment, buses and trains as components in their braking, shifting and door opening/closing systems. They also assist in the portable refrigerant recovery equipment.

Performing important functions in the operation of heavy duty commercial equipment, they play a key role in the laundry industry to control water entry to the machine. Solenoid valves are used in the operation of bottle and dish washing equipment, as well as the car wash industry and photographic processing. Additional uses are found in the operation of office copiers and printers. They control paint sprayers and fuel dispensing systems. Solenoid valves can be found in medical and dental equipment such as analyzers and sterilizers.

Chemical plants, petroleum refineries, off-shore oil platforms, distillation plants, sewage treatment facilities, and grain elevators all use explosion proof valves for safety. In the paintball industry, solenoid valves are commonly used to control a larger valve used to control the propellant (usually compressed air or CO2).

Solenoid valves are used in fluid power pneumatic and hydraulic systems to control cylinders, fluid power motors or larger industrial valves. They are found in shop floor applications from product and process test equipment to machine tool equipment, industrial compressors including welding and flame cutting machinery.

Solenoid-controlled valves are often used in irrigation systems, where a relatively weak solenoid opens and closes a small pilot valve, which in turn activates the main valve by applying fluid pressure to a piston or diaphragm that is mechanically coupled to the main valve. Automatic irrigation sprinkler systems also use solenoid valves with an automatic controller.

Other common uses for solenoid valves are in central heating. The solenoid valves are controlled by an electrical signal from the thermostat to regulate the flow of heated water to the heating elements within the occupied space. Solenoid valves are in humidifier reservoirs to maintain proper climate control. They are also used in systems that reclaim refrigerant from window and roof top air-conditioning systems.

As you can see, solenoid valves play an important role in keeping the wheels of industry turning!

 

 

Founded in 1918, Parker Hannifin Corporation is a global company with annual sales exceeding 14 billion dollars per year. Parker Hannifin is the world's leading diversified manufacturer of motion and control technologies and systems, providing precision-engineered solutions for a wide variety of mobile, industrial and aerospace markets.

The company employs approximately 57,500 people in 50 countries around the world. Parker’s engineering expertise and broad range of core technologies uniquely positions the company to solve some of the world’s greatest engineering challenges.

Parker Hannifin Corp product lines consists of...

To view detailed information on each of the "solenoid valves" detailed in this post, please visit our Parker Skinner catalog. If you need more information, call our experts at 1.818.700.8838 or email us at sales@gghyd.com.

Let us know how this newsletter affected your understanding of the industry in which you are a part. Your response to our “GGHYD - What is…Series” is critical to its success. So, please feel free to add your comments, request more information or suggest a topic of discussion. We'd love to hear from you.

A solenoid valve is designed to control the flow of liquid or air. These valves can be made from various materials depending on their purpose, including steel, brass and plastic. Solenoid valve operation is comprised of two basic functions, normally open and normally closed. A normally open valve closes when energized and a normally closed valve opens when energized.

Let’s take a look at possible solenoid valve malfunctions. Then we can discuss how to troubleshoot the valve and perform repairs. We will also consider some maintenance tips to increase the life of a solenoid valve.

There are five primary solenoid valve malfunctions:

Regardless of the issue, it is important to determine why the problem occurred. Let’s do some troubleshooting.

When a valve fails to open or close, the most likely causes are either an electrical or a mechanical malfunction. Determining the cause of a malfunction requires several steps that include the following:

  Nameplate

The nameplate identifies the valve’s performance features. Low voltage or an increase in pressure may cause a valve to malfunction. Damage to the seals or other internal components may be a factor causing the unit to malfunction. In some cases, simply cleaning the valve may resolve the issue. Depending upon the media flowing through a valve, a robust filtration system may be necessary to maintain an efficient system.

  Solenoid valve is making too much noise when activated

First, turn off the power source. The components of the device that are most likely to have failed are either the sleeve or the plunger (housed inside the pressure vessel) or coil. Check for wear, damage, or excessive amounts of debris. Removing the debris or replacing the damaged parts that keep the solenoid valve from closing will allow the plunger to make the proper contact.

A secondary problem could be insufficient supply voltage. Check the voltage to ensure that it is at least 85% of the rating listed on the valve’s nameplate.

If the valve is leaking externally, the cause is generally a worn seal or O’ring. You should also check the screw torque to ensure that screws are not over or under tightened at the cover or sleeve.

When a valve leaks internally, the problem is usually dirt or other foreign objects caught in the assembly. Disassemble the valve so as to be able to clean it thoroughly using a mild solution made from soap and water to clean each part. Remove any foreign objects found in the orifice. Any internal parts that are worn or nicked will need to be replaced, including the spring on the plunger return.

Occasionally, due to heat issues, you may encounter a problem with the coil. When the voltage is too high, the coil may overheat. To correct the problem, simply replace the damaged coil. To prevent a repeat problem, the source of the overheating needs to be eliminated. Check the voltage coming from your power supply to ensure that the coils you are using are compatible. Conversely, when the voltage is too low the coil may not function, so knowing the voltage coming from your power supply is crucial to proper solenoid valve operation. One other concern with coils is moisture, but this is primarily only an issue with tape-wound coils that are rarely used in today’s applications. If you are using plastic or epoxy coils, heat is a greater concern than moisture or dust.

Preventing a problem from occurring is often far more convenient than fixing one in an emergency. Regular maintenance is a necessity when:

Here are some basic maintenance rules for keeping your solenoid valves working at full capacity:

Media and applications, ie. dry air and rapid cycling, can potentially stress the valve. Using a liquid media lubricates the valve and increases the number of cycles a valve will see before maintenance is required. When no liquid media exists, the valve may require maintenance as little as every 100,000 cycles.

G&G Hydraulics Corporation sells replacement part kits designed specifically for the valves we offer. Having a replacement parts kit on-hand is always a good idea and allows the operator to head off further issues.

Following are three important factors to consider when performing a system’s maintenance program:

Two issues need to be addressed before you start the maintenance process. First, disconnect the valve from the power supply. Second, depressurize the valve. Other safety precautions will vary depending on the media being used in the system.

  Coil Inspection

Check for damage to the coil as this is usually one of the first parts to fail. A coil that is damaged, burned, or melted must be replaced. You may also need to go back to the troubleshooting section and determine why the coil was damaged. Determining the cause of the failure can prevent further issues. Be careful not to place a power supply on a coil that is not installed in the valve system. This will usually burn a coil out immediately.

  Cleaning

While you have the unit disassembled, be sure to clean the internal components thoroughly with water and a mild detergent. Debris is a major cause of solenoid valve failure.

  Caution

Do not power-up the system until you are sure that everything has been reassembled properly.

If you experience problems or have a concern that is not covered within this article, please contact us at info@gghyd.com, call us at 1.818.700.8838 x 201 or click here. Our knowledgeable engineering staff is available to assist you in answering any questions or concerns!