Which Hydraulic Valve is Best for You?
We are often asked about the right hydraulic valve for an application. While we are always ready to assist you, we feel that you should also know the specifics yourself to make the right decision.
In this post, we will start with the absolute basics that every customer should know. Afterward, we will delve deeper into hydraulics and share our insights with you. Let’s start.
Hydraulic Valve
Hydraulic valves are mechanical elements that regulate the operation of a hydraulic system [1]. They do so by limiting, directing, or stopping the flow of liquid in the hydraulic circuit’s different lines.
Types of Hydraulic Valves
Hydraulic valves are usually categorized into either of the three main categories by function – pressure control, flow control, and directional control [2]. While uncommon, some valves fall into two categories due to having multiple functions.
Pressure Control Valves
While low pressure may result in the insufficient transmission of force, higher pressures can burst pipes. Therefore, pressure in the hydraulic systems is to be managed within range and is done by pressure control valves [3]. Pressure control valves, in turn, are of several types. The function of the most commons is summarized in the table below.
| Pressure Control Valves | |
|---|---|
| Type | Function |
| Relief Valves | Protects the hydraulic circuit from an overload |
| Reducing Valves | Limits the pressure in a line below the main circuit’s pressure |
| Unloading Valves | Unloads the pump by transferring the excess liquid to the tank at times of limited operation |
| Pressure Switches | Actuates electrical circuit at a preset pressure |
| Counterbalance Valves | Offers hydraulic resistance to an actuating cylinder to prevents rapid movement |
| Sequence Valves | Provide a sequential and alternate passageway to the main circuit at a preset pressure |
Directional Control Valves
As the name suggests, directional control valves control the flow direction. There is much diversity in the directional control valves, from the construction and type to the number of connections and mode of operation. Nevertheless, here are some basic and common variants that will help you understand the other types as well.
| Directional Control Valves | |
|---|---|
| Type | Function |
| Check Valve | Allows fluid to move in only one direction |
| Shuttle Valve | Allows high-pressure fluid to pass through while blocking the low-pressure fluid |
| Spool type valve | By sliding movement of a spool, it allows/restricts fluid movement to two or more ports. |
Flow Control Valves
Flow control valves control the flow rate of the fluid through the system. As the flow rate directly affects the actuator’s speed, flow control valves are used to manage the actuator’s speed. It will be easy to remember these valves as they are not so different from the mainstream flow control valves. Have a look at the table below.
| Flow Control Valves | |
|---|---|
| Type | Function |
| Gate Valves | Generally used for on/off operations |
| Globe Valves | Like the gate valve but can be partially opened to adjust the flow without concern of wear. |
| Diaphragm Valves | Ideal for harsh conditions involving corrosion and contamination. |
| Needle Valves | Used for flow adjustments in the hydraulic circuit. |
Final Thoughts
By now, you should be able to pick the right type of hydraulic valve for you. Still, we need to go through the operating conditions and the manufacturer’s nomenclature for selecting the exact valve. Stick around, and you will get to read about that right here. Moreover, you can also learn more about directional control valves at our previous post.
Despite that, if you ever encounter a problem in making your decision or want someone to review your choice, you can always contact us. Our application engineers are always happy to answer your queries.
References
[2] Department of the Army, Hydraulics. Washington, DC, 2017.
[3] Y. Kogyo, “Basic Hydraulics and Components,” p. 97, 2006.
