A solenoid valve is a device that controls the flow of fluid through it. The solenoid’s motion usually occurs in two separate phases: a back and forth motion called an “open” or “closed” position and then an upward or downward movement. It is used to control pressure or other variables such as temperature. Solenoids can be made from many materials, including metal alloys, plastics, and composites like fiberglass-reinforced epoxy resin composite (FRX). All types of solenoids operate on the same basic principle. When current flows through them, they cause electrical impulses, which change shape in response to current flow through them by changing shape along their length to open or close their passage points (valves).
TYPES OF SOLENOID VALVES
Direct-Acting Solenoid Valve
Direct-acting solenoid valves are used in applications where the flow rate and operating pressure are relatively low. In these types of applications, the flow rate and operating pressure are directly proportional to the required size of the solenoid. For example, if you need a valve that can handle a flow rate of 1 liter per minute at a pressure of 10 psi, then you must use a solenoid with an orifice size that is ten times larger than your application’s minimum orifice size.
Internally Piloted Solenoid Valve
Inner pilot-operated solenoid valves are suitable for applications with high flow rates and high pressures. Valves of this type are opened or closed by pressure across them. This is achieved by installing an orifice or equalizing a hole. Cores block flow on orifices in most designs. The diaphragm is pressed on both sides when the valve is closed, allowing fluid to pass through the orifice. As soon as the flow of fluid is interrupted, a closing force is generated due to the large effective area above the diaphragm.The core opens the orifice by opening the valve, relieving pressure at the diaphragm’s top. When the line pressure is high, the valve opens.
Internally piloted solenoids are used in large industrial applications where there needs to be a high flow rate and small leak rate due to their ability to handle pressures above 100 PSI in some cases, depending on the design.
Externally Piloted Solenoid Valve
Externally piloted valves include two basic types: internally piloted and externally piloted. These valves apply the same concept as internally piloted valves, but the pressure to actuate the valve comes from fluid from an external source. A self-contained fluid circuit is integrated into the valve via an additional port.
Direct or servo-assisted solenoid valves are internal and external piloted solenoid valves.The main actuating force comes from the valve’s differential pressure upstream and downstream.
SOLENOID VALVES FLOW PATH
Two-way Solenoid Valves
Two-way solenoid valves control flow in and out of a system. The valve can be configured as normally open and normally closed; the normal state means de-energized. In a normally open valve, the opening occurs when the valve is de-energized, and the closing occurs when it is energized. The opposite is true for customarily closed valves.
The two-way solenoid valve has one upstream and one downstream port and is used to block or allow fluid flow. The valve can be configured as either normally open or normally closed; the normal state means that it is de-energized. A normally open valve opens when de-energized and closes when energized again. This type of valve will remain de-energized until power is applied to it, at which point it will return to its original state (open or closed).
Three-way Solenoid Valves
Typically, a three-way solenoid valve has three ports: an inlet (pressure port), an exhaust port, and an outlet (actuator port). The valves can also be configured as normally open and normally closed, with the addition of a universal function. De-energizing a three-way valve causes fluid to flow from its inlet to its outlet port while blocking its exhaust port. During energized operation, the inlet port closes, and the outlet port connects to the exhaust port.
Three-way solenoid valves can also control flow from one point to another by using a universal function. This means that when one or both of the ports are open, fluid will flow through them; however, if either or both are closed, no fluid will flow through them.
Four-way Solenoid Valves
Four-way solenoid valves work by controlling the flow of water through a pipe. The valve has four ports: an inlet, two outlets, and an exhaust port. The first inlet port connects to a pressure source, while the second and third connect to other pipes or devices. The fourth port controls the flow of water from one outlet to another.
It must consider several factors when selecting the correct solenoid valve body and seal materials. These include the process fluid, the environment of the application, and the cost.
Process fluid is determined by what type of fluid is being used in the process. For example, it makes sense to use a material with high wear resistance and strength if it’s an oil refining process. Using a material with high corrosion resistance is ideal if it’s a water treatment process.
Environment plays a role in how well a particular material can withstand extreme changes in temperature or pressure without failing. So, for example, if it’s being used in an oil refinery and there’s an accident where there’s high pressure coming out of pipes or valves; this could cause parts to fail quick because they’re made from inferior materials that aren’t designed for this kind of stress on them over time.
Cost is another factor when deciding which materials to use for your project because different materials cost different amounts.
COMMON APPLICATIONS OF SOLENOID VALVES
Solenoid valves have a wide range of possible applications.They can be found in all types of machinery and are particularly useful in applications requiring precise control. For example, in the construction industry, solenoid valves are used to control water flow through irrigation systems, while they are also used in oil drilling to help prevent fluid loss. In addition, they are often used to power MRI scanners and other diagnostic equipment in the medical field.
You can use it for pneumatic, hydraulic circuits, and automation. Industrial and manufacturing plants are often used as actuators for valves and other control systems. Medical, pharmaceutical, and food manufacturing industries also use this type of valve. Semiconductor materials are widely used to manufacture electronic components because they have good electrical conductivity but low resistance (R). This property makes them ideal candidates for use in solenoid valves that require smooth operation with low power consumption.
- Fast response time
- Low power consumption
- Remote operation
- Suitable for a wide spectrum of machinery and applications
- Cheap replacement parts
- Compatible with both DC and AC voltage
- Low and High-temperature usage
- Safety external leakage block
- You can install it vertically or horizontally.
Solenoid valves are often the workhorse of any system. They are durable and reliable, but they do have their disadvantages. The most common issue with solenoid valves is that they can experience problems when the voltage feed passed through is too low or too high. It will cause the magnetic field to either strengthen or weaken, causing the valve to stay open or close incorrectly. The correct voltage is vital to opening and shutting the valve correctly. If not set correctly, the valve will wear faster and cause the coil to break.
- Sensitive to voltage
- If the magnetic field setting is incorrect, the valve will partially close
- Coils may need to be replaced during the life of the valve
- The control signal must stay on during the operation
- Valve fluid can be affected by the flow (pre-valve flow is always more significant than the backflow of the valve)