Flushometer piston

• US 5,881,993 A
• Filed: 09/25/1997
• Issued: 03/16/1999
• Est. Priority Date: 09/25/1997
• Status: Expired due to Term

• Current Assignee: Sloan Valve Company
• Original Assignee: Sloan Valve Company
• Inventors: Wilson, John R., Carroll, Daniel J.
• Primary Examiner(s): Walton, George L.
• Application Number:
  US08/937,881
• Time in Patent Office: 537 Days
• Field of Search: 251/40, 251/120, 251/121, 138/40, 138/45, 138/46
• US Class Current: 251/40
• CPC Class Codes: E03D 3/04 with piston valve and pressure chamber for retarding the valve-closing movement
• CPC Class Codes: F16K 31/3835 the discharge being effected through the piston and being blockable by a mechanically-actuated member making contact with the piston

Abstract

A flush valve includes a body with an inlet, an outlet, a valve seat at the outlet, and a piston movable in the body toward and away from the valve seat to control flow through the outlet. The piston has a chamber and there is a refill orifice in the piston connecting the chamber with the body inlet. Pressure in the chamber maintains the piston closed upon the valve seat. A relief valve in the piston vents the chamber to the outlet to permit the piston to move away from the valve seat to open flow from the inlet to the body outlet. The piston has a guide portion which extends downstream of the valve seat when the piston is in the closed position. The guide portion of the piston has a plurality of outwardly extending axial ribs, the outer surface of which is radially in alignment with the path of flow through said valve seat. The piston area between the ribs is closed by a skirt to confine the path of flow exteriorly of the piston portion to provide a defined flow path through the valve seat from the inlet to the outlet.

Claims

1. A flush valve including a body having an inlet and an outlet, a valve seat at said outlet, a piston movable in said body toward and away from said valve seat to control flow from said inlet through said outlet, said piston including a chamber, a refill orifice in said piston connecting said chamber with said body inlet, pressure in said chamber maintaining said piston closed upon said valve seat,

a relief valve in said piston for venting said chamber to said outlet, means for opening said relief valve to vent said chamber causing said piston to move away from said valve seat to open flow through said outlet,

said piston having a guide portion which extends downstream of said valve seat, said guide portion having a plurality of outwardly extending axial ribs, the outer surface of which is radially in alignment with the path of flow through said valve seat, the piston area between said ribs being closed by a skirt to confine the path of flow exteriorly of said guide portion to provide a defined flow path through said valve seat from said inlet to said outlet, said skirt reducing back pressure on said relief valve and terminating short of said axial rib termination to reduce pressure drop across the piston to increase flow rate,

said piston having a seat portion formed and adapted to close upon said valve seat, said piston having an inwardly beveled outer surface directly adjacent and upstream of said seat portion, with said inwardly beveled surface increasing water flow past said piston when it is away from said valve seat, a throttling ring on said piston directly downstream of said seat portion and directly upstream from said axial ribs, said ring throttling flow through said outlet just prior to closure of said piston upon said valve seat.

2. The flush valve of claim 1 characterized in that said ribs are generally circumferentially equally spaced and are at least four in number.

3. The flush valve of claim 1 characterized in that said piston has a seat portion formed and adapted to close upon said valve seat, said piston having an inwardly beveled outer surface upstream of said seat portion, with said inwardly beveled surface increasing water flow past said piston when it is away from said valve seat.