You may have come across the term poppet valve in the past but have no idea what it is. Well, that's not a problem because this article seeks to explain what it is and its uses in detail.
So, what is a poppet valve?
A poppet valve is a valve used to regulate and control the quantity and timing of gas or vapor flow into an engine. It is often called a mushroom valve.
The poppet valve is said to have been invented by E.A.G Young of Newcastle and Frenchtown Railroad in 1833. He moved on to patent this innovation but sadly, the Patent Office fire that happened in 1836 destroyed all available records, including his.
Looking carefully at a poppet valve, you will find a round or oval hole and a tapered plug. These valves are a disk shape on the bottom of the shaft. This shape is referred to as a valve stem. The part of the hole that makes contact with the plug is known as a "valve seat" or only "seat."
The shaft provides cover for the plug portion by sliding through a valve guide. A pressure differential aids in sealing the valve in exhaust application. While in intake valves, a pressure differential will open the valve.
How does it work?
The movement or mode of the poppet valve is quite phenomenal. In contrast with other valves like the oscillating valves and slide valves, the poppet valves work to not move the seat.
Oscillating and slide valve movements involves either sliding or rocking over a seat uncovering a port. However, with the poppet valve, it merely lifts from a seat exhibiting a movement perpendicular to the port's plane. This unique movement of the poppet valve makes it function without lubrication.
Most times, it is wiser to have a balanced poppet in a direct-acting valve. All forces acting on the poppet are made of no-effect because of the equal and opposite forces present.
Thus, less power is required to aid the movement of the poppet valve. A more straightforward way to explain how a poppet valve works is by using a sink as a case study and thinking of the valve as a plugin for the sink. When this plug in the sink is removed, the flow path rapidly opens up, and more content can flow through faster and efficiently.
Uses of Poppet valve
You will find them used in several industries in engines and other quick reacting processes because of their fast-flowing and acting nature. A poppet valve is a directional control valve with a large flow pathway. Diverse industries use poppet valves; for one, they are used to control the flow of milk, and in the semiconductor industry, it serves the purpose of isolating air.
Nonetheless, the most common sectors you will find a poppet valve will be in sectors that use internal combustion engines and steam engines. In the launching of torpedoes from submarines, a poppet valve plays a vital role. In this case, torpedoes are expelled from the tube by a system that uses compressed air to expel. Here the poppet valves perform the function of recovering a large quantity of air alongside a substantial water body.
It does this to minimize the tell-tale cloud of bubbles that might negatively affect the boat's submerged position. Pneumatic tires make use of Presta and Schrader valves, which are typical examples. These tires have no spring in them and dependent on pressure differential for opening and closing when inflated.
Other uses of a poppet valve include:
- They are useful as relief valves in air tanks.
- They provide a convenient way to prevent flow reversal in a fluid circuit. This helps to avoid contamination caused by the mixing of different media.
- Some poppet check valves, however, allow reverse flow. A typical example is a hydraulic lift. In this system, the valve allows fluid flow into the cylinder, holding the piston's position. To lower it, the fluid allowed to flow into the cylinder will undergo a reversal through the valve.
- They are instrumental in positive displacement pumps as it serves as unloading valves in this system.
Advantages of Poppet Valves
- They do not need any lubrication. This is advantageous in picking valves where chemical compatibility with various fluids is a determining factor.
- They are useful for systems involved in delivering medical gases or any system that needs clean and dry air.
- In hydraulic systems, lubrication is not an area of concern as the hydraulic fluid serves as a lubricant.
- This valve is self-cleaning. This cleaning happens when the valves open and allows a large flow through it; this flow washes away any contaminant present from dirty air.
- In comparison to spool valves, a poppet valve is less expensive to make. Spool valves require the presence of precision boring valve bodies and machine spindles. However, the economical solution here is by duplicating a multi-way spool valve with multiple three-way poppet valves. The poppet valve's other characteristics are factored in. These characteristics are low wear and fast response, amongst others.
- A poppet valve is a valve used to regulate and control the quantity and timing of gas or vapor flow into an engine. This valve is useful in several industries on engines and other quick reacting processes because of its fast-flowing and acting nature. It is a directional control valve with a large flow pathway.
- The passage where the valve stem moves up and down is called a guide. The valve face is the name given to the head of the valve.
- There is a lot of talk about where the origin of the name "poppet" came from. Some may think it is because these valves make a popping noise when in operation, but they don't (although some valves may act so).
- The name was likely inspired by the word "puppet," especially if you consider how the engine poppet valves dance on and off their seats controlled from above; it may just make sense after all.
- The introduction of "poppet" in the description of a valve is the same word used for marionettes. They move bodily, responding to small motion transmitted linearly. Before the time, "puppet valve" was used synonymously with "poppet valve." This approach has, however, become outdated.