Another object of the invention is to provide a diaphragm valve wherein the valve seat is mounted on, or comprises a portion of, a removable valve seating ring.

Yet another object of the invention is to provide a diaphragm valve comprising: a valve body having a chamber, a fluid inlet passage and a fluid outlet passage communicating with the chamber through openings in a wall of the chamber;Cast Steel Valves a diaphragm disposed in the chamber and dividing the chamber into an operating chamber and a valve chamber; a removable seating ring disposed against the wall in the valve chamber, the seating ring having a first passage extending therethrough and communicating with the fluid inlet passage and second passage means communicating with the valve chamber on opposite sides of the seating ring, the valve seating ring having a valve seat disposed thereon and surrounding the first passage on a first surface of the seating ring facing the diaphragm; and, valve operating means for selectively moving the valve into contact with the valve seat to block flow of a fluid from the fluid inlet passage to the valve chamber.

A further object of the invention is to provide a diaphragm valve as described above and further comprising a diaphragm holder for pressing against a first surface of the diaphragm in a peripheral region of the diaphragm, the seating ring having a peripheral projection on its first surface against which the diaphragm is pressed to thereby clamp the diaphragm.

Another object of the invention is to provide a diaphragm valve as described above wherein the seating ring is provided with first and second annular projections on a second surface of the seating ring facing the wall, Plug Valvesthe first annular projection surrounding the first passage and the second annular projection extending along the periphery of the second surface, the first annular projection extending outwardly from the second surface of the seating ring further than the second annular projection whereby the first annular projection forms a fluid seal with the wall when the diaphragm is pressed against the peripheral projection on the first surface of the seating ring. The first annular projection extends outwardly on the order of 0.5mm further than the second annular.WATER POWER CONTROL VALVE The second annular projection and/or the valve seat may comprise a synthetic resin material disposed in a groove or groves provided on the seating ring. Alternatively, the seating ring and the valve seat, the seating ring and the second annular projection, or the valve seat, seating ring and second annular projection may comprises a monolithic body, preferably made of metal.

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