We have been somewhat busy the last few weeks completing a new project. The next few blog entries should be more timely.
These valves are used for multiple purposes in ammonia refrigeration systems. However, they are commonly designated by a single description. This common term of hand expansion valve (HEV) is sometimes misleading. It may help to consider the actual function the valve provides; throttling of liquid or vapor and the mass flow requirements for the application.
The common applications of this valve are:
- Liquid make-up to maintain a relatively constant liquid level in a vessel.
- Throttling liquid from a higher pressure to a lower pressure (control pressure systems).
- Balancing upstream liquid pressures to evaporators in a liquid overfeed system.
- Throttling vapor flow in float columns to minimize rapid liquid level fluctuations.
The next few blog entries will discuss the multiple applications of these valves.