Valve Seat and Seat Ring Basics: What to Know
It’s always ideal to fully understand all compressor valve components and their great importance. Read further to learn about the functions of the valve seat and seat ring.
Compressor valves come in an array of shapes and sizes, but all of them have one thing in common: the valve seat. And with the valve seat, there typically is a valve seat ring. Working in conjunction with each other, as well as with other parts of a valve, the seat and seat ring creates an airtight environment that facilitates the proper function of a valve.
The valve seat is a surface inside the body of a valve that comes into contact with the disk, which is a moveable component that restricts and allows flow through the valve.
It has several important purposes, including the following:
- Preventing compressed or combustion gasses from getting into the manifold.
- Permitting a particular amount of heat to travel through the valve to the cylinder head.
- Maintaining the proper seal of a mounted valve.
- Reducing wear-resistance by resisting pressure and high heat.
Valve Seat Ring
The valve seat ring creates a shutoff surface. Typically held in place by pressure, a seat ring may also be threaded and screwed into the valve body. The seat ring is a crucial part of maintaining the strength of the seal within the valve and facilitating a seal that is free of leaks.
As crucial as they are, the valve seat and seat ring do not work alone. Other important compressor valve components include:
- Gaskets –These aid in creating airtight seals within valves. These are especially useful for filling out imperfections in machined parts that would otherwise compromise the airtightness of the valve.
- Springs – These facilitate rapid opening and closing of the valve to allow and restrict flow through the valve. Springs can be crafted from a variety of materials to accommodate different operating environments, including stainless steel, copper, and others.
- Valve plates – these, working in concert with other valve parts, regulate the flow of air or fluid in a valve.
Periodic inspection of all compressor valve parts, including the seat and the ring, is recommended to ensure your machines remain in good working order.
Valve seats are an important part of the configuration of both intake and exhaust valves. Other components include the valve itself, the valve guide, a spring seat, valve spring, and spring retainer. When all of these components are working together appropriately, the combustion chamber can retain the quality of airtightness that is essential for operation.
In addition, the cylinder liner, cylinder block, and seat rings must be in good working condition to ensure that air does not escape inappropriately.
The valve seats are important for at least the following four important functions.
- Compression gas sealing. The purpose of this is to prevent compressed gasses or combustion gases from escaping into the manifold.
- Heat transfer. This involves allowing a certain amount of heat to move through the valve into the cylinder head.
- Maintaining the strength of the seal when the valve has been mounted. This is one area where the quality and integrity of the valve seat rings are crucial.
- Reduce wear-resistance. The entire valve seat must be able to withstand the pressure of high heat and high loads.
In addition to these functions, there are some characteristics that valve seats must display. These begin with a smooth operation between the seat and the partner valve.
Next is the ability to keep work processes low in order to keep operating within a reasonable cost.
Finally, the seats and rings must be easy enough to machine in order to prepare them for specific applications.
Although valves may come in a variety of shapes and sizes, nearly all require valve seat rings. The rings provide a stable surface for shut off purposes. The rings are held into position by the pressure where the bonnet is fastened to the body of the valve. Some rings are threaded, but this is not appropriate for all applications. They are often beveled to provide assistance in guiding the valve during the closing process. Without the seat rings, it would be difficult to obtain the necessary leak-proof seal.
Dealing With Compressor Valve Flutter
Valve flutter is one of the major contributors to degradation in performance and lowering of reliability. The mechanism is not unlike swinging a baseball bat against a well-seated metal pole. At the moment the bat strikes the pole, there is a chatter that sends a high frequency vibration up the arms of the person swinging the bat. This happens because the bat does not reach a dead stop when it first hits the pole but bounces just a little.
Valve flutter is also a high frequency opening-and-closing action that works against a smooth and solid valve close action. It also increases the stress and wear of the valve components.
Well-designed components eliminate flutter by manufacturing the specifications to a specific window of operating conditions. Technicians can ensure high-performance, high-reliability installations by carefully choosing the valve which matches the specific conditions of the installation. For complex systems, designers often work with the on-site engineers at the provider site to ensure proper part selection.
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