Investigation of solenoid valves and their types
A solenoid valve is an electromechanical valve that operates using an internal actuator in the form of an electric coil and a piston. An electrical signal controls the opening and closing of the solenoid valve . There are two modes in which solenoid valves are produced. They are usually open and usually closed. The solenoid (electric coil) works using AC or DC. The DC power supply is supplied by a battery, generator or rectifier. While the AC power supply is usually taken from the mains AC voltage through the transformer.
Valve solenoid application
A Wolverine solenoid is used to open, close, mix, or direct a liquid or gaseous medium in an application. Solenoid valves are widely used in industrial and domestic sectors. The use of solenoid valves ranges from the control of standard process valves to the control of special valves such as overpressure protection systems and emergency stop valves, as well as fluid control in applications such as fire system valves.
The main advantage of solenoids over general valves is the very fast response time. Some common programs include:
- Solenoid valves in refrigeration systems reverse the refrigerant flow that cools in summer and warms in winter.
- Solenoid valves in compressors are used in the start-up phase to discharge the compressor to reduce engine torque.
- Solenoid valves are used in irrigation systems for automatic control purposes.
- Solenoid valves in washing machines and dishwashers control the flow of water as needed.
- Air pressure in air conditioning systems is controlled by solenoid valves.
- Car washes and industrial cleaning equipment use solenoid valves to control water, soap or chemical flow.
- The entry and exit of water in water tanks is often controlled using solenoid valves.
- The pressure, flow and direction of the fluid in the solenoid valves are controlled in various dental and medical equipment.
How to work with solenoid valve
The valve solenoid has two main components: the coil and the valve body (G). The following figure (Figure 1) shows the typical components of the Volora solenoid. The electromagnetic induction coil (A) around an iron core in the center is known as a piston (E). At rest, it will usually be open (NO) or usually closed (NC). In the no-energy phase, a valve is usually left open while a closed valve is usually closed. When current flows through an electric coil, it receives energy and creates a magnetic field that creates a magnetic attraction with the piston. For this reason, the piston moves by overcoming the spring force (D). For a normally closed solenoid, the piston is removed and the (F) seal opens the opening, allowing the media to pass through the valve. While normally open for the solenoid, the piston moves downward, sealing the (F) seal of the hole, preventing media from passing through the valve. The shading ring, as shown by (C) in Figure 1, prevents vibration and noise in the AC coils.
Read the article about solenoid valve for more information .
Solenoid valves are used to automatically control the flow of liquids and gases. In different types of programs and equipment, they are increasingly used. Different types of designs are available to suit a specific application.
Types of solenoids though
Valves are classified into three groups depending on the number of solenoid tube connections.
- Two-way solenoid
- Three-way solenoid
- Four-way solenoid
As the name implies, a two-way solenoid has an inlet and an outlet. They can be classified into two types.
Two-way solenoid
- Normal closed structure: The valve closes when neutralized and opens when fed.
- Normally open structure: This type of solenoid closes when fed and opens in the event of a power outage.
Three-way solenoid
Three-way solenoid valves have three pipe connections and two openings. When one hole is open, another closes, and vice versa. Three-way solenoid valves are usually used intermittently to apply pressure and release pressure from the diaphragm valve or single cylinder. They operate in the following three modes:
Normal closed structure : When the valve is disconnected, the pressure port is closed and the outlet port is connected to the cylinder port. When the valve is activated, the pressure port is connected to the cylinder port and the outlet valve closes.
Normally open structure : If the valve is cut off, the pressure port is connected to the cylinder port. But when the valve is activated, the pressure port closes and the cylinder port connects to the outlet port.
General structure : This type allows the valve to be normally closed or normally open. In addition, it may even be connected to select one or two ports or to transfer current from one port to another.
Four-way solenoid
Four-way solenoid valves are used to operate the double cylinders. These types of solenoid valves have four or five tube connections. One pressure, two cylinders and one or two exhausts. In one valve position, pressure is connected to the cylinder port. Another is connected to the exhaust. In the other valve position, the pressure and output at the cylinder connections are reversed.
Depending on the function of the solenoid valves, they are classified as:
- Solenoid valves for general use
- Stiffness of the shot even though
- Process control valves
General purpose solenoid valves : This type of Volvo solenoid is a normally open or normally closed valve used to control fluid flow. However, these valves do not act as safety valves.
Shut-off Valve Stiffness : This is usually a “connected” or “disconnected” valve that operates using a safety control device to prevent unsafe fluid transfer. A multi-port valve can act as a shut-off valve rigidity relative to its conventional closed port.
Process control valve : This type of valve solenoid is approved for the control of flammable gases but does not act as a reliable shut-off valve valve.
Depending on the method, solenoid valves are divided into the following four groups:
- Solenoid valves with direct function
- Pilot solenoids
- Solenoid valves under pressure
- Solenoid valves function with air.
Valve solenoid with direct operation
In a direct-acting solenoid, the core directly opens the mouth of a normally closed valve or closes the mouth of a normally open valve. The size of the opening and the pressure of the fluid determine the force required to open the valves. As the size of the opening increases, the required force also increases.
Pilot solenoid valves
This type of solenoid, however, is equipped with a pilot and a smaller aperture. They use line pressure for operations. When the solenoid is activated, the pilot orifice opens and immediately releases pressure from the top of the valve piston or diaphragm to the valve outlet. This creates an unbalanced pressure that forces the line pressure to lift the diaphragm piston from the main opening and open the valve.
When the solenoid is disconnected, the pilot orifice closes and full line pressure is applied to the top of the piston or diaphragm through the orifice, creating a closed force for a tight closure.
Solenoid valve under pressure
These types of solenoid valves are usually diaphragm or piston valves. They are usually equipped with a 3-way or 4-way electric pilot that controls the opening and closing of the main valve using working pressure.
Solenoid even equipped with air
This type of valve solenoid has two basic functional units.
An operator with a piston or diaphragm assembly that creates a force when pressed.
Even with an orifice in which there is a plug or disk to connect or stop the flow.
Pistons are commonly used for pneumatic operations, while low pressure operators and air pressure instruments typically use diaphragms.
Solenoid valve housing
Depending on the application of the solenoid valves, the electrical coils are enclosed using a variety of enclosures. Their main purpose is to protect the coil against dust, indirect spraying, water and so on.
Selection of solenoid valves
Choosing a particular type of solenoid is not easy. A number of physical and operational factors are required when choosing a Wolverine solenoid for a particular application. Some of these parameters are:
Pressure:
There are various pressure terms that you should know before choosing a solenoid. they are:
- The maximum operating pressure difference that the lubricant solenoid must overcome to open or close the valve must be determined during selection.
- Similarly, the minimum pressure drop that is present during flow across the valve is required.
- Safe static pressure at which the valve is pressed during normal service.
- Constant pressure is usually considered to be 5 times the safe working pressure.
Temperatures:
Similar to the pressure as mentioned above, the following temperature must be specified:
- Minimum, maximum and normal ambient temperature
- Maximum fluid temperature
Viscosity:
The viscosity of the fluid at operating temperature is also an important parameter when selecting a solenoid valve.
Response time:
The response time of the valve is the passage of time for the solenoid valve to move from the open state to the closed state or vice versa. Depending on the size of the valve, the response time of the solenoid is different. It also depends on the type of power supply, fluids used, temperature, pressure and pressure drop.
Solenoid valve type:
Depending on the needs of the program, the need for a three-way or three-way solenoid should be determined. Decide in advance whether a particular application requires a direct, indirect, or semi-direct solenoid.
Solenoid valve housing material:
Based on the chemical properties and ambient temperature of the flow and the environment, the valve material is determined. Common solenoid materials include brass, stainless steel, PVC and polyamide.
Solenoid valve size
It is very important to measure and select the right type of solenoid because both small and large valves have different side effects. The main factors that are considered when measuring a loader solenoid are:
- Minimum and maximum currents to be controlled.
- Minimum and maximum pressure difference on solenoid valve
- Specific gravity, temperature and viscosity of the fluid used.
- Inlet and outlet pipe diameter
- Power supply voltage.
The optimal size of a voloba solenoid is determined by the current velocity, which allows you to determine the current coefficient (kv). The flow coefficient shows the volume of water at room temperature that flows through the solenoid even with a pressure drop of 1 time for one minute.
Solenoid valve symbol
Like other lions, there is a special symbol for solenoid valves. Figure 2 below shows the solenoid valve symbol.
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