Under normal atmospheric conditions chlorine (CL₂) is a greenish, yellow gas with a biting penetrating odor. It is nonflammable, but it supports combustion at higher temperatures. Chlorine, like other halogens, is highly reactive. When it reacts with water, it forms hydrochloric and hypochlorous acids, both of which are highly corrosive. Chlorine is compressed and liquefied for shipping, storage, and handling because it boils at -30°F at atmospheric pressure.

With chlorine being such a hazardous substance, the Chlorine Institute recommends only top outlets, as opposed to bottom outlets, for chlorine storage tanks. This represents a serious restriction in designing a liquid chlorine transfer system from storage tanks to loading facilities or other processes. The Lawrence Vertical Liquid Chlorine pump has been specifically developed for mounting on the top nozzle of the pressurized liquid chlorine tank.

Design Features

An adjustable gland mechanism permits packing tightening from the outside. In case of packing failure, the emergency seal may be pressurized to prevent chlorine leakage.
The instrumentation package provides for a controlled flow of buffer gas to the air chamber. Vapor pressure in tank is reference pressure.
Thermocouples monitor the temperature of the lower packing. Excess heating automatically shuts the pump down.

The sudden closing of the check valve creates a high pressure water-hammer effect. The chamber is filled with liquid chlorine gases and when the check valve slams shut the water-hammer shock waves are absorbed by the surge chamber. The shockwaves are kept from passing down the discharge pipe into the the stages of the pumping equipment which could result in fracturing the pump casing internals.

The enclosed carbon steel impellers are equipped with sealing surfaces on both the front and back shrouds. For "wet" chlorine applications monel is available, as is stainless steel for toxic services other than CL₂. The radial sealing ring surfaces allow variations in impeller clearances without affecting overall performance. Since chlorine is usually pumped when boiling, NPSHA is equal to submergence above the centerline of the impeller minus friction losses in the suction. To avoid pumping down under cavitation conditions, a suction inducer is available on all sizes. It will lower NPSHR and thereby reduce chlorine inventory in the tanks.