A solenoid valve is a type of valve that uses theenergeny of a solenoid armature to open or close the flow through the valve. The armature is an electromagnet with coils around it that changes its shape when electricity flows, which forces a change in the valve.
The main difference between a 2-way and 3-way solenoid valve is their number of circuits. A 2-WAY SOLENOID VALVE has one open and closed circuit at any given time, while a 3-WAY SOLENOID VALVE has three courses operating simultaneously. Various types exist but are technically classified as “solenoid valves.”
2 Way Valve Operation solenoid valve
A 2 Way Solenoid Valve has two circuits on it at all times. One open circuit and one closed circuit; whenever the solenoid is energized, the circuit is energized until the solenoid is de-energized. When one of the circuits is energized, current flows through that particular circuit using a coil in series with a fixed resistor and then to the ground. This current flow through the series combination of loop and resistor causes the armature to move to push a fluid flow through the valve. This movement closes off or opens up a path for fluid to pass.
When the solenoid is de-energized, no current flows in the circuit through the coil and resistor, effectively opening a path for fluid to pass. The fluid movement within the valve (in this case, because it is a two-way valve) creates an equal but opposite pressure on either side of the valve. This causes one side to be opened while the other side is closed. These two sides are normally open (NO) and normally closed (NC). This action occurs until a strong enough force moves one of the armatures back into place, resulting in a change in direction for fluid movement through the circuit and eventually back to normal.
This type of valve is used throughout many applications. These include applications where you will have many devices that need to be shut off or on simultaneously. The most common uses for this type of valve include inline ball valves, check valves, and safety relief valves.
3-Way Valve Operation
A 3 Way Solenoid Valve has three circuits operating at any given time. This is done because three possible combinations can result in movement one way or the other in a solenoid valve: one closed circuit, two closed circuits, or three open circuits; this results in a total of four possible positions for fluid to flow through the valve which is why solenoid valves are called 4-way valves.
In this 3-way valve, the flow through the three circuits is a closed circuit and two open circuits. When the solenoid is energized, current flows through the two available courses, which causes an equal and opposite current to flow through the closed circuit, creating an equal but opposite flow of fluid. This causes one side to be opened while the other side is closed. These two sides are normally labeled open (NO) and normally closed (NC). This action occurs until a strong enough force moves one of the armatures back into place, resulting in a change in direction for fluid movement through the circuit and eventually back to normal.
One other type of solenoid valve is the check valve. This solenoid valve will only operate in one direction, open or closed. This is achieved because the two channels are perpendicular to each other. When the current flow into one channel stops and the flow in the other stops, two equal and opposite forces occur simultaneously, which keeps the armature from changing position (thereby creating equal but opposite pressure on both sides of the valve). This allows pressure to be built up on both sides.
The flow direction through the valve depends on which channel the current flows into first. The current flow will always go into the channel with a lower resistance (the smaller channel) first and then go into the rest of the media in order of their size.
This type is used in Valves designed specifically to keep liquid or gas flow from flowing back into a system or out of a tank. The most common use for check valves is in drain and supply lines to prevent reverse flow and back siphoning. This valve is often installed at the end of piping runs draining, filling, or bleeding air out of tanks, piping systems, and filter beds.
MULTI-WAY SOLENOID VALVES
This type of valve has a limited amount of circuits functioning at any given time. In this case, there is an infinite number of possible combinations. The flow through the valves depends on which channels the flow of current flows through in order. The current flow will always go into the channel with a lower resistance (the smaller channel) first and then go into the rest of the media in order of their size.
This type is used in several applications but is most commonly used as a door-opening and closing application with more than one control panel (or button).
Advantages and Disadvantages of 2-Way and 3-Way Valves
There are some advantages and disadvantages with 2-Way and 3-Way Solenoid Valves:
Advantages:
Flexibility is one of the main advantages of a solenoid valve. Variables can be programmed into the solenoid valve, making it useful in applications such as ball valves, safety equipment, check valves, and other actuators. This can be done without the need for additional boxes or wiring. The same amount of space can be saved using this actuation mechanism over different types that require an electrical box and a solenoid valve. This also reduces the amount of space needed for the equipment in applications with limited floor space, like under a hood or in a cabinet-mounted device.
There are some disadvantages to solenoid valves:
These valves are electronic devices, making them susceptible to corrosion from things like water, atmospheric contaminants, and other things. Also, solenoid valves require special attention when it comes to wiring. A small mistake or miswiring can devastate the valve and cause a fire or explosion. There is also a problem with shorting out of the circuit, which can create an electrical shock hazard and damage the actuation mechanism and other components around it at worst or cause erratic behavior at best. There is also an issue with the mechanical design of solenoid valves. A slight delay in response time causes this. When the valve is called upon to open and close, there will be a few milliseconds of unnecessary movement of fluid through a circuit that was supposed to have been completed before calling upon the valve to perform this action, which causes problems in some applications. Sometimes it can even cause the failure of other components.