Hydraulic Valve Types and Working Methods

Hydraulic Valve Types and Working Methods

Hydraulic Valve Types and Working Methods

Hydraulic valves are a type of valve system used to control fluid flow. They are commonly used in hydraulic systems, especially in hydraulic power transmission and control. Hydraulic valves are designed to control the pressure, flow rate and direction of hydraulic fluid (usually oil).

These valves can have a variety of structural and functional features and come in different types for different applications. Some common types of hydraulic valves include pressure control valves, flow control valves, diverter valves, flow control valves, and mixer valves. These valves are designed to ensure the desired operation of hydraulic systems and are used in a variety of industries, such as automotive, construction, agriculture, mining and industrial machinery.

1. Duties of Valves
• Turns fluid path on and off.
• Changes the direction the fluid travels.
• Sends the fluid to the tank.
• Adjusts the operating speed of the receivers by controlling the flow rate of the fluid.
• Protects circuit elements against high pressures. It sends the rising fluid to the tank.
• It controls the pressure of the fluid and ensures that the circuit elements operate at certain pressures.
• Controls the pressure, flow, direction of the fluid at certain time intervals.
• Some valves may perform one or more of the tasks listed above.

2. Pressure Control Valves
These are the valves used in the pressure lines of hydraulic systems, ensuring that the pressure of the fluid is at the desired value.

Types according to the places used;
2.1. Pressure Relief Valves
It permits the formation of sufficient pressure to overcome the resistance to be realized for the realization of the work.

2.2. Pressure reducing valves
It may be necessary to use multiple user elements (cylinders, hydromotors) which are required to be operated at different pressures in the hydraulic circuits and the user elements may need to work at different pressures. In such cases, pressure reducing valves are used. Normally in the open position. There are different types of two-way and three-way.

2.3. Pressure sorting valves
Pressure sorting valves are used in a hydraulic circuit to operate a plurality of user elements such as cylinders and motors at different times and pressures. Operating principle Similar to pressure relief valves. Normally closed. It opens at the desired pressure and activates other user elements.

2.4. Drain valves
It is used to send the hydraulic fluid to the Hydraulic Tank. Normally closed valve opens when the warning comes and sends the fluid to the tank.

3. Directional Control Valves
They are the valves that determine when and in which way the fluid must follow in hydraulic circuits. They change the flow path if desired; if desired, they open and close the flow path.

3.1. Schematic Illustration of Directional Control Valves
• Each position of the valve must be indicated by a square.
• The flow direction of the fluid is indicated by arrows.
• Closed roads are identified by a horizontal line.
• Valve connections are indicated by dashes.
• Marking of valve positions; valve positions are marked with letters from left to right. For three-position valves, the center position is indicated by 0.

3.4. Lettering of valve connections;
• P = Pressure line A, B, C .... = Work line or working line
• R, S, T = Tank (return) line
• X, Y, Z = Pilot (warning) line
• L = Leak line

3.5. Identification of directional control valves;
• 2/2 = Number of paths / Number of positions
• When the 3/2 valve designation is made, the valve is 3-way, 2-position. 3.6. Normal positions of wafers;
• In hydraulic circuit drawings, the valves are drawn and lettered in their normal position.

Hydraulic valves come in many different types with a variety of structural and functional features. Here are some common types of hydraulic valves:

1. Pressure Control Valve: It is used to keep the pressure level within a certain range. It can be divided into subcategories such as overpressure valves and pressure reducing valves.

2. Clutch Valve: It functions to open or close power transmission by controlling the pressure in the hydraulic system.

3. Direction Valve: Controls the flow direction of the hydraulic fluid. They can be unidirectional, bidirectional or omnidirectional.

4. Flow Control Valve: Controls the flow rate of hydraulic fluid. This is used to provide precise movements in the control of moving equipment.

5. Mixer Valve: It is used to combine or separate more than one fluid. For example, it can be used to combine or separate different functions in hydraulic systems.

6. Return Valves: Used to control the rotational movement of hydraulic cylinders. They are generally used to control high-energy movements in hydraulic systems.

7. Automatic Control Valve: Automatically controls the flow or pressure in hydraulic systems based on a certain condition.

8. Flap Valve: It is used to control the air pressure of the hydraulic tank and prevents air intake in the system.

These are just a few examples. Hydraulic valves come in many different types customized for different applications in various industries. Depending on the requirements of the application, it is important to select the appropriate valve type.

4. Valve Malfunctions
There are some problems that occur repeatedly during operation. The most common of these are; Defective Control Element Excessive Leak Defective or broken Springs Adhesion or Stiffness Cracked or Broken Parts Most valve failures are caused by problems elsewhere in the system. Unless the actual fault is corrected, you can wait for the recurrence of faults with valves that have been repaired or replaced. General inspection of parts; visual inspection of defects such as protrusions, cuts, roughness, notches, cracks, wear marks or bent parts. Place on a flat surface laterally and roll as shown in the figure. visually inspect for wobble indicating distortion.

Valve Malfunction Symptoms may occur in the following ways. Sludge: Substance formed by oxidation due to overheating of hydraulic fluid. Scratch: Small grooves caused by abrasion on the surface of a valve by high pressure fluid. Knock: Noise, muzzling, buzzing from the constant impact of the control tip to the solenoid body due to insufficient or overcurrent. Whenever you remove a valve for repair or maintenance, always install a new seal, even if all seals appear to be in good condition.

Working Methods of Hydraulic Valves

Hydraulic valves are components used to control fluid flow in hydraulic systems. Methods of operation may vary depending on valve type and application, but in general hydraulic valves have several basic methods of operation:

1. Pressure Difference: A hydraulic valve can operate by using the pressure difference between different points of the system. For example, the pressure difference can enable a pressure control valve to maintain a certain pressure level. The pressure difference can trigger the valve to open or close when it reaches a certain pressure level.

2. Mechanical Force: Some hydraulic valves operate with externally applied mechanical forces. These types of valves can usually be opened and closed manually or through a mechanism. For example, a hydraulic valve operated by a hand controller can control flow by being moved by a mechanical force.

3. Electrical Control: Some modern hydraulic valves can be controlled by electrical signals. These types of valves can be opened and closed using electromagnetic coils or motors. It is widely used in applications such as electrical control, automation and remote control.

4. Hydraulic Control: Hydraulic valves can operate under the influence of hydraulic forces. For example, a directional valve can use hydraulic pressure to change the direction of movement of a hydraulic cylinder.

5. Thermal Control: Some hydraulic valves may operate sensitively to thermal effects such as temperature changes. These types of valves can be opened and closed with an increase or decrease in temperature or fixed within a certain temperature range.

These operating methods demonstrate how hydraulic valves can be used in a variety of applications. Each type of valve may use a different operating principle to perform a specific function and should be selected based on the requirements of the hydraulic system.

Things to Consider When Choosing a Hydraulic Valve

It is important to pay attention to a few important issues when choosing a hydraulic valve. Here are some issues to consider when choosing a hydraulic valve:

1. Application Requirements: First, it is important to determine the requirements of the application in which the hydraulic valve will be used. These requirements may include factors such as pressure range, flow rate, environmental conditions, etc.

2. Flow and Pressure Values: It is important to determine the flow and pressure values appropriate to the requirements of the application. The hydraulic valve controls the flow rate and pressure in the system, so these values must be compatible with the valve capacity.

3. Working Environment Conditions: The conditions of the environment in which the hydraulic valve will be used should also be taken into consideration. For example, factors such as high temperature, low temperature, corrosive environments are important for the valve material and its durability.

4. Reliability and Durability: The hydraulic valve must be reliable and durable because hydraulic systems often operate under heavy workloads. Choosing a quality valve is important for system performance and reliability.

5. Ease of Maintenance: When choosing a hydraulic valve, it is important that it is easy to install, maintain and repair. Easily accessible parts and properly designed parts that require maintenance can reduce operating costs.

6. Compatibility and Integration: The hydraulic valve must be compatible and integrated with other system components. Especially in complex hydraulic systems, it is important that the valve is compatible with other components.

7. Maximum Efficiency and Performance: It is important that the hydraulic valve selected meets the requirements of the application and provides maximum efficiency and performance. Correct valve selection is important for energy saving and operating efficiency.

These factors are the main considerations in hydraulic valve selection. Fully understanding the requirements of the application and selecting a suitable valve ensures that hydraulic systems operate efficiently and reliably.