What is the Difference Between Single and Double Solenoid Valve

In construction machinery and hydraulic systems, single solenoid valves and double solenoid valves are two common types of hydraulic valves that have unique functions and characteristics in controlling the flow of fluids. Single solenoid valves and dual solenoid valves differ in their principles of operation, structure, and application, so it is especially important to understand their differences when choosing the right type of valve.

 

Structure and Principle

1.Structure and Principle of Single Solenoid Valve

A single solenoid valve, as the name suggests, consists of a solenoid coil and a spool. This spool is usually a moving part with a sealing element. When the solenoid coil is energized, it generates a magnetic field that attracts the spool, causing a break between the sealing element and the valve seat. Liquid fluid can then flow through the valve. When the solenoid coil is de-energized, the magnetic field disappears, and under the action of the spring, the spool returns to its original position, and the sealing element re-contacts the valve seat, thus cutting off the liquid flow.

 

2.Structure and principle of double solenoid valve

A double solenoid valve is slightly more complex than a single solenoid valve, it consists of two separate solenoid coils and a spool, this solenoid coil may be a 24v or 12 volt solenoid coil. This spool also has a sealing element, but its structure allows it to be controlled by two solenoid coils respectively. When one solenoid coil is energized, the spool is attracted, opening one of the passages and allowing liquid to flow. When this solenoid is de-energized, the spool returns to its initial position, closing that passage. When the other solenoid coil is energized, the valve spool moves again, opening another channel and realizing the two-way flow of liquid.

 

3.Single solenoid valve and double solenoid valve difference

Structure: single solenoid valve only a solenoid coil and a spool, while the double solenoid valve has two solenoid coils and a spool, the structure is more complex.

 

Function: single solenoid valve can only control the unidirectional flow of liquid, while the double solenoid valve can realize the bidirectional flow of liquid, with a stronger fluid control capability.

 

Control mode: single solenoid valve by energizing and de-energizing to control the switch of the hydraulic system, while the double solenoid valve through the control of the two solenoid coils to achieve the switch of different channels.

 

Application: Due to the bidirectional flow characteristics of the double solenoid valve, it is more common in some of the engineering machinery applications that require fluid to flow in different directions in the system, while the single solenoid valve is mostly used for single-direction control scenarios.

 

Functions and applications

1.Function and application of single solenoid valve

Function: Single solenoid valve is a basic diesel solenoid valve commonly used in hydraulic systems, mainly used to control the one-way flow of liquid. It opens the valve by attracting the spool through the magnetic field generated when it is energized, allowing the liquid to flow in one direction. When the solenoid coil is de-energized, the spool returns to its original position by the action of the spring and the valve closes, cutting off the flow of liquid.

 

Application: Single solenoid valve is widely used in the hydraulic system of construction machinery, such as excavators, loaders, bulldozers and so on. It is often used to control the unidirectional movement of the hydraulic cylinder to achieve a variety of mechanical operations, such as bucket rod expansion and contraction, bucket lifting and lowering. In addition, it can also be used to control the hydraulic system pressure, flow and other parameters, to achieve simple hydraulic control functions.

 

2.Double solenoid valve function and application

Function: double solenoid valve is more complex compared to a single solenoid valve, which contains two independent solenoid coils and a spool. This makes the double solenoid valve can control the two-way flow of liquid. When one of the solenoid coils is energized, the spool is attracted and opens a channel allowing the liquid to flow in one direction. When this solenoid is de-energized, the spool returns to its initial position, closing that passage. When the other solenoid coil is energized, the valve spool moves again and opens another channel, allowing the liquid to flow in the opposite direction.

 

Application:Double solenoid valve has a wider application in the hydraulic system of construction machinery. It is often used to control the bi-directional movement of the hydraulic cylinder to achieve diesel engine parts complex mechanical operations, such as forklift forks rise and fall. At the same time, double solenoid valve is also commonly used to realize the system's bidirectional flow control, such as hydraulic motor forward and reverse control, improve the flexibility and functionality of the hydraulic system.

 

Energy efficiency and control

1.Energy Efficiency and Control of Single Solenoid Valves

Energy efficiency: single solenoid valve is relatively simple, there is only a solenoid coil used to control the unidirectional flow of liquid. Due to its simple structure, its energy utilization efficiency is usually high. In operation, a single solenoid valve only needs to be briefly energized to open the valve, the spring will return the spool to its original position after the power failure, no need to continue to consume energy, so there are certain advantages in saving energy.

 

Control: Single solenoid valves control the switching of the hydraulic system by energizing and de-energizing the valve. When energized, the solenoid coil generates a magnetic field to attract the spool, so that the valve is open and the liquid flows; when the power is cut off, the magnetic field of the solenoid coil disappears, the spool is returned to its original position by the action of the spring, and the valve is closed to cut off the flow of liquid. Because the single solenoid valve only one-way control capability, so in some two-way flow control scenarios may not be flexible enough.

 

2.Double solenoid valve energy efficiency and control

Energy efficiency: double solenoid valve compared to a single solenoid valve is slightly more complex, it contains two independent solenoid coils and a spool, used to control the bidirectional flow of liquid. Due to its more complex structure, compared to the single solenoid valve in the energy utilization will be slightly reduced. However, the energy efficiency of the double solenoid valve is still quite high because only one solenoid coil operates during power-up or power-down, while the other one remains off, eliminating the need for constant energy consumption.

 

Control: Dual solenoid valves control the bi-directional flow of liquids by separately controlling two solenoid coils to switch different channels on and off. When one of the solenoid coils is energized, the spool is attracted and opens a channel, allowing the liquid to flow in one direction; when this solenoid coil is de-energized, the spool returns to its initial position and closes the channel. When the other solenoid coil is energized, the spool moves, opening the other channel and allowing the liquid to flow in the opposite direction. The bi-directional control capability of dual solenoid valves makes them more flexible and suitable for applications that require liquids to flow in different directions in a system.