Posted on : Friday 29th May 2020 04:57 PM
Working with pneumatics or hydraulics can be rewarding. You want to ensure that the air and gas flows are steady so that the machines can do their job. That whooshing is reassuring, as long as you know the machine’s supposed to make that sound. But what will you do on the days that the machine doesn’t work? You’ll need to check the valves.
You need to have the right valves to control air flow. Otherwise, too much pressure at the wrong time can cause an explosion, while too little pressure means that no work gets done. Valves open and close to regulate airflow, either partially or fully. You want a valve that doesn’t open or close abruptly, however, because the shock can cause damage to a machine.
This is where directional control valves, come into the fray. These valves regulate the flow of liquids or gases in pneumatic machines to control work, often from different sources, and open and close rapidly. They determine in which direction the liquid or air will flow, into which chamber. As you can imagine, they are highly useful.
Some types of directional control valves can shift positions quickly while opening and closing. This is especially useful for cylinders, which also change positions while in motion because the wrong position could lead to a broken part or even the engine failing. Others can regulate actuator speed, which is useful for customizing pacing on a project.
How Does A Directional Control Valve Work?
To open and close, a directional control valve consists of a spool and a cylinder at the basic level. The spool is either sliding or rotary; sliding means that it rotates based on a set of cylindrical grooves, while rotary indicates that the valve rotates based on a set of spherical grooves. As the spool rotates, the valves open and close.
Directional control valves use different types of energy to open and close. You can use manual, electrical, pneumatic, hydraulic, or solenoid energy depending on the model and their specifications. Manual valves rely on gears and wheels to function, which is why they tend to wear down the fastest.
Our Recommendations For Directional Control Valves
How do you know which valve is right for you? Many factors come into play. Size is one; how big or small does the valve need to be, relative to the machine? You need to know what can and cannot fit into the system. Budget is another factor; the more complicated the valve, the costlier each individual unit will be.
There are also different types of valves: discrete, digital, and proportional. Discrete valves are the most basic, that focus simply on changing positions to conform to the established pneumatic system. They use a spool to manipulate liquid flow into a maximum of three separate directions. These valves are best for when you have a relatively simple machine, and only need a few different paths for liquid or air flow. We recommend that discrete valves are a good starting point, especially when you have a tight budget for parts and repairs.
Digital valves have more parts and more flexibility. While they only operate in the “on/off” function, they use three parts to seal pathways efficiently when they are closed. When you want a strong seal, these are a good idea. A check valve is the simplest digital type, which prevents backflow and thus prevents congestion of air or liquids while a valve is open. You can get more complicated if you wish, depending on the design of the machine and what you want the directional control valve to accomplish.
What about proportional control valves? They work best in systems that require varying pressure and flow for different tasks. The valve uses solenoid forces to determine the direction of fluids and gas, as well as the pressure levels. With that said, because they accommodate various pressures and flow directions, proportional control valves are best for machines and systems that don’t have abrupt changes. They adjust slowly.
The number of ports also can determine what kind of valve you need. Ports define if your valve is one, two or three-way in terms of direction. You can manage multiple directions if you have more ports, but then you are paying for more specialization. Definitely, double-check your budget.