Abstract: A refrigeration and defrost system utilizing various valves for opening a defrost line to hot gas and regulating the pressure in refrigerant lines. A slug surge suppressor is provided at several points in the defrost and refrigerant lines to alleviate hydraulic shock damage caused by liquid/gas "slugs" passing rapidly through the lines. The slugs are commonly formed by the required rapid opening of the various valve of the system. Capillary passages in the suppressor resist liquid flow while allowing gas to flow freely.

Abstract: An improved gas pumping recirculating refrigeration system is disclosed. A controlled pressure flash tank provides flash gas for forcing liquid refrigerant from a dump tank. A controlled pressure receiver receives liquid from the dump tank and recirculates it to an evaporator. The flash gas pressure in the flash tank is controlled by a pressure regulator valve connected between the controlled pressure flash tank and the controlled pressure receiver. The pressure regulator valve may set so that the flash gas in the flash tank is at the pressure needed to force liquid from the dump tank. Thereby, optimum refrigeration efficiency is achieved with very little energy waste.

Abstract: A refrigeration system utilizing hot gas for defrost and a hot gas defrost valve with specific opening characteristics for rapidly reducing the pressure gradient across the valve without producing hydraulic shock. When defrost is called for by the system, the hot gas defrost valve is opened in a manner which prevents a liquid or liquid-gas slug from impacting on cold system components and producing liquid hammer effect damage.

Abstract: A refrigeration and defrost system utilizing various valves for opening a defrost line to hot gas and regulating the pressure in refrigerant lines. A slug surge suppressor is provided at several points in the defrost and refrigerant lines to eliminate hydraulic shock damage caused by slugs of a liquid-gas mixture passing rapidly through the lines. The slugs are generally formed by the required rapid opening of a hot gas defrost valve and a pressure regulatory valve of the system. A series of capillary passages in the suppressor are operative to resist the flow of liquid while allowing gas to flow freely. Tangential velocity is imparted to the slug to separate the liquid and gas components of the slug.