Valve
A valve is a device that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways.
Characteristics
In distilling there are four main attributes we look at when comparing valves:
- Start/Stop: This is the amount of time it takes to turn fully on to fully off (and visa versus). When deciding why type of valve to use you should understand if you need to turn it on or off in a hurry.
- Absolute volume(of flow/max flow):
- Flow Control: How precisely will controlling the flow matter?
- Controlling the direction of fluid flow: Only used for a check valve, not applicable for others
Major types
Ball Valve
A ball valve is the most common type of valve that is used in distilling due to its low cost. It best used is in situations where the valve will be used fully open or closed like moving water or mash from one container or another. Ball valves offer inconsistent flow rates even when moved to the same position.
- Start/stop: It is very easy to turn fully on to fully off.
- Absolute Volume: Ball valves allow full flow of water for a given diameter of pipe.
- Flow Control: Flow control is difficult with a ball valve.
Gate Valve
A gate valve is less common. It offers some control over flow while still allowing full volume of fluid to pass. This valve is useful for situations that requires some control but not fine control. Control to a condenser would be a good use.
- Start/stop: It is slower to turn fully on to fully off than a ball valve.
- Absolute Volume: Gates valves allow full flow of water for a given diameter of pipe.
- Flow Control: Flow control fairly easy but not precise.
Needle Valve
Needle valves are used where precise flow control is needed. Needle valves are common in Liquid Management] type stills.
- Start/stop: It is very slow to fully turn on and off.
- Absolute Volume: Needle valves reduce the available volume to pass.
- Flow Control: Flow control is easy and precise.
Butterfly Valve
- Start/stop: It is easy to fully turn on and off.
- Absolute Volume: Allows full volume for diameter of pipe.
- Flow Control: Flow control difficult.