Abstract: A valve body having an opening and a cover for closing the opening is provided with confronting sealing surfaces each having a circumferential recess of a specific shape to receive an elastic sealing ring; the sealing ring is provided with a tab which projects externally of the valve when assembled to indicate to proper positioning of the seal ring upon assembly; a process for manufacturing mold parts using a lost foam method includes replicating a valve part in styrene, forming a sand mold about the styrene and then pouring molten metal into the mold to destroy the styrene and fill the mold cavity thus formed.

Abstract: A tamperproof fire hydrant which can only be operated with use of a special operating means or tool thus preventing the opening of the hydrant by unauthorized persons for unauthorized use. The hydrant is provided with the usual polygonal end portion of the rotatable operating nut extending out of the top closure member. A dome shaped cap is mounted on the polygonal end portion of the operating nut for free rotation relative thereto, the dome shaped cap having a skirt with the lower edge thereof spaced from the tubular hold down nut or top closure member of the fire hydrant to provide a limited access space to the polygonal end portion for reception of the special operating means. The special operating means is also capable of being used as a tool to remove the nozzle cap off of the usual nozzle and to install the hose coupling on the nozzle.

Abstract: A tamperproof fire hydrant which can only be operated with the use of a special operating tool thus preventing the opening of the hydrant by unauthorized persons for unauthorized use. Additionally the tubular hold-down nut for the operating nut is so designed to prevent unauthorized disassembly of the hydrant by unauthorized personnel. To prevent unauthorized use or unauthorized disassembly the polygonal shaped operating nut is concealed by a dome shaped cap covering both the hold-down nut and the operating nut, the cap being freely rotatable with respect thereto. The dome shaped cap permits only limited access to the operating nut. Additionally the hold-down nut for the operating nut is also protected in this manner and is provided with a specifically shaped outer surface which requires a special tool usable only when the dome shaped cap for the operating nut is removed.

Abstract: A tamperproof fire hydrant which can only be operated with use of a special operating means or tool thus preventing the opening of the hydrant by unauthorized persons for unauthorized use. The hydrant is provided with the usual polygonal end portion of the rotatable operating nut extending out of the top closure member. A dome shaped cap is mounted on the polygonal end portion of the operating nut for free rotation relative thereto, the dome shaped cap having a skirt with the lower edge thereof spaced from the tubular hold down nut or top closure member of the fire hydrant to provide a limited access space to the polygonal end portion for reception of the special operating means. The special operating means is also capable of being used as a tool to remove the nozzle cap off of the usual nozzle and to install the hose coupling on the nozzle.

Abstract: A backflow preventer apparatus designed for connection between a supply pipe having liquid under pressure and a service pipe, the backflow preventer apparatus comprising a pair of check valves in series and defining a zone therebetween, a relief valve operable upon a change in differential pressure across the upstream check valve, and a vacuum breaker operable upon a drop in pressure in the zone to a predetermined pressure supply above atmospheric pressure. The differential pressure operable relief valve, when opened upon certain operating conditions, causing the zone to drain to atmosphere. The vacuum breaker operates independent of supply pipe pressure or service pipe pressure but solely on a drop in pressure in the zone.

Abstract: A backflow preventer apparatus designed for connection between a supply pipe having liquid under pressure and a service pipe, the backflow preventer apparatus comprising a pair of check valves in series and defining a zone therebetween, a relief valve operable upon a change in differential pressure across the upstream check valve, and a vacuum breaker operable upon a drop in pressure in the zone to a predetermined pressure supply above atmospheric pressure. The differential pressure operable relief valve, when opened upon certain operating conditions, causing the zone to drain to atmosphere. The vacuum breaker operates independent of supply pipe pressure or service pipe pressure but solely on a drop in pressure in the zone.

Abstract: A gate valve structure for use in large diameter mains carrying fluids under high pressure, the gate valve structure being provided with an improved annular resilient seal for engaging a valve seat of the type where the valve seat provides for a face-seal and an edge-seal with intermediate sections making both a face-seal and an edge-seal. The annular resilient seal member is provided with a pair of arcuate bulges oppositely disposed thereon at positions to engage the face-seat surface of the valve seat adjacent the face-seat surface's minimum radial thicknesses to provide an increased contact in this area when the gate member is in the closed position. Additionally, the improved gate valve structure utilizes opposed ribs in the elongated chamber of the casing, the ribs being received in guideways or recesses in the periphery of the gate member so as to guide the gate member during opening and closing. Such an arrangement permits the use of smaller and lighter valve casings for large diameter mains.