![]() ![]() Typically, this pressure will be very low (1-5 bar or 15-75 pounds per square inch), depending on which surface area is used to open the valve. The purpose of the spring is to hold the valve closed whenever there is no pressure in the system. When no pilot pressure is applied, the valve can be opened with only the pressure required to compress the spring. The most important thing to understand about pilot-to-close logic valves is that if pilot pressure is applied, the valve will stay closed. A pilot-to-open logic valve is also available, but it is not used as often. This ensures the pilot side always generates the most force whenever the same pressure is applied to either the bottom or side as is applied to the top. At 3 square inches, the pilot surface is the largest of the surface areas. The dotted line to the top surface area indicates a pilot line. There is also a hole on the top, and another hole on the bottom. As you can see, the side surface area is accessed by holes in the side of the cartridge. Note the three surface areas in Figure 1 – one on top, one on bottom and a third on the side. While their schematic symbols may take some getting used to, they represent their function very well. Their design may be simple or complex, although generally they are quite simple. The valves can also handle large amounts of flow with accuracy. They can emulate almost any type of hydraulic valve and can be used as directional controls, pressure controls, check valves and flow controls. Unless you have X-ray eyes like Superman, you must rely on a schematic to understand the hydraulic flow. Therefore, it’s more important than ever to understand how to read and use a hydraulic schematic as a troubleshooting tool. Troubleshooting a system with valves that you cannot see can be confusing. Of course, there is a downside to having valves mounted in a manifold. Obviously, if a hydraulic line no longer exists, it can’t leak. Less real estate is required inside a plant, and fewer leaks are observed. Installation then becomes more a matter of plumbing large manifolds together than installing individual valves. Manifolds can be assembled before a unit is shipped. plants begin to be more conscious of energy costs, more American-made machines are using logic valves.īecause the valves are mounted in a manifold, less plumbing is required, so the installation costs are lower. This might explain why so many European machines have used these valves for decades, as historically energy costs have been higher in Europe than in the United States. Now, more of the energy that goes into the system can be directed to the product, and less is wasted on the mechanical machine operation. This allows the use of smaller actuators, making the systems much more efficient. Over time, hydraulic systems are being operated at higher and higher pressures. This enables them to cope with high pressures better than conventional hydraulic plumbing. ![]() Logic valves have distinct advantages, primarily because they are mounted in a manifold. Liquid Notes for Windows and Mac is available from Plugin Boutique at a 60% discount until August 18th, 2014.A logic valve alongside the valve it represents
0 Comments
Leave a Reply. |