Hydraulic valve
What is hydraulic valve?
A hydraulic valve is a mechanical device designed to control the direction of liquid, usually oil, through a hydraulic circuit. Crucial to any hydraulic system, they can regulate the speed of motors and movement of cylinders.
Typically constructed of steel, iron or other metals, valves are designed to operate under high-pressure conditions to ensure the efficiency and performance of hydraulic systems at all times.
Where some systems may require just one hydraulic valve, others may use multiple to guarantee optimum efficiency.
How Are the Types of Hydraulic valve Classified?
★ Classified by function
Hydraulic valves can be divided into three categories according to their uses: directional control valves (such as one-way valves, reversing valves, etc.), pressure control valves (such as relief valves, sequence valves, pressure reducing valves, etc.), flow control valves (such as throttle valves, flow valve, speed regulating valve, etc.).
These three types of valves can also be combined into combination valves as needed to reduce pipeline connections, make them more compact, simple to connect, and improve efficiency. The more commonly used ones are combination valves composed of one-way valves and other valves, such as one-way pressure reducing valves, one-way sequence valves, one-way throttle valves, etc.
★ Classified by manipulation method
Hydraulic valves can be divided into manual valves, motorized valves, electric valves, hydraulic valves, etc. according to the control method.
★ Classified by control method
(1) Fixed valve or switch control valves include ordinary control valves, cartridge valves and superimposed valves.
(2) Electro-hydraulic control valves include electro-hydraulic servo valves, electro-hydraulic proportional valves and electro-hydraulic digital valves.
The servo control valve is a type of valve that continuously controls the direction, pressure and flow of liquid flow in the hydraulic system based on input signals (such as electrical, mechanical, pneumatic, etc. signals) and feedback quantities;
The proportional control valve is between A valve between ordinary control valves and servo control valves. It can continuously control the direction, pressure and flow of liquid flow in the hydraulic system in proportion to the size of the input signal. However, the control accuracy is not high. It is a kind of valve that has both A control valve with certain servo performance and relatively simple structure;
The digital control valve uses digital information to directly control the opening and closing of the valve port, thereby controlling the direction, pressure and flow rate of the hydraulic oil flow in the hydraulic pump or system.
★ Classified by installation method
(1) Pipe connection: Pipe valves adopt threaded connection, also known as threaded connection.
(2) Plate connection: Install valve components on a special connection plate.
(3) Integrated connection: In order to make the structure compact and simplify the pipeline, the valves are arranged centrally, including integrated block type, superimposed valve type and cartridge valve type.
Do you know the most common hydraulic valves?
The three most common types of hydraulic valves are: Directional control valves, Pressure control valves and Flow control valves.
★ Directional control valves
Directional control valves can also be referred to as switching valves. They are used to control the direction, acceleration or speed of an actuator and have the ability to start, stop and pause the flow of liquid through the system.
The classification of a directional control valve is indicated by a standardised number system which specifies how many spool positions and working ports it comprises. The spools within a directional control valve can be actuated in different positions, and typically slide or rotate within the valve, to allow the hydraulic fluid to flow through the open ports.
Generally, they contain at least two spool positions and two working ports – these are known as 2-way valves and are the most simple of directional control valves, which will be clearly stated as 2/2. Another commonly found directional valve is a 4-way (4/3), which signifies four port valves with three achievable positions (neutral, extend and retract).
★ Pressure control valves
The function of a hydraulic pressure control valve is to regulate the pressure of the fluid travelling through the pipe in a hydraulic system.
1. Pressure relief valves
Pressure relief valves work to limit the maximum pressure by opening when the highest input pressure is reached, and feeding any excess flow from the system back to the tank.
2. Pressure reducing valves
Unlike pressure relief valves which control the input pressure, reducing valves work to control the output pressure. For example, if the output pressure of a hot water system is too high, this can affect the water flow and overall performance of the system.
A pressure reducing valve will help to ensure a consistent flow of water by reducing the pressure in one part of the circuit to a lower level than the system pressure, to achieve the set value.
3. Pressure valves with fixed throttle
These types of valves also offer pressure controlling capabilities, with the assistance of a switching task to allow a change in the position of the valve to happen suddenly when required, as opposed to gradually as with other pressure valves.
★ Flow Control Valves
Hydraulic flow control valves are used to regulate speed within a specific part of the hydraulic system to ensure optimum performance at all times. By maintaining the flow rate and pressure of the fluid, they directly regulate the speed of motors and cylinders.
The most common types of flow control valves are gate valves, needle valves, diaphragm valves, pinch valves and globe valves.
Directional Control VALVE
The directional control valves are widly used in follow machines : forklift, snow clearer,machine tool , hydraulic system, loader ,mining machinery , Aerial truck, snow plow, road roller, garbage truck, gravel crusher, hydraulic crane, excavator mining machinery and so on .
How to choose a directional control valve
hydraulic solenoid valve
A solenoid is a device comprised of a coil of wire, the housing and a moveable plunger (armature). When an electrical current is introduced, a magnetic field forms around the coil which draws the plunger in. More simply, a solenoid converts electrical energy into mechanical work.
We can provide YUKEN Series 、REXROTH Serie solenoid valve
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Hydraulic valves are easily replaced within an existing circuit, but when designing a new hydraulic system this requires greater knowledge and understanding of the set expectations in order to select the correct product. If you need help in choosing a hydraulic valve, we can help.
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