The double seated No. 27 float valve is the type most widely used for the automatic control of the supply of liquids to an open tank where dead-end closing is not essential and where valve inlet pressures are normal. Both angle and globe pattern bodies are available in every pipe size. Many thousands are in use on both large and small water, oil, and chemical storage tanks in all types of industries. Where a drip-tight closing float valve, or a float valve for a higher then ordinary pressure is required, one of the single seated valves should be selected.
The single seated No. 7 and No. 77 internal pilot controlled float valves are commonly used to maintain a water level in an open tank and can be recommended for use wherever tight closing is essential. These float valves are best suited for clean liquids not injurious to neoprene, leather, brass, or iron parts and where the standard design temperature is below 125°F. The neoprene valve disc and leather cup can be replaced with Teflon for temperatures above 125°F and below 350°F. The minimum and maximum inlet pressures for the No. 77 float valve are shown in the table below.
The No. 777 float valve is recommended for applications requiring a tight closing valve for cold or hot liquids which are not injurious to the rubber diaphragm or disc, and for pressures up to 150 PSI.
The ball type inner valve, which has been used for years with excellent results in other valves, is now being built into float and lever valves. It provides a simple and durable, tight closing construction suitable for any ordinary fluid at temperatures up to 406°F.
The No. 177 is a single seated main valve which is controlled externally by the included No. 112 pilot float valve. The No. 177 is suitable for clean water at temperatures up to 125°F and for pressures up to 250 PSI and is used especially where tight closing is essential. The No. 177 valve can operate at a distance from the tank - which may be open or closed - so it lends itself to a wide variety of installations.
