Relief valve

Abstract

A relief valve for relieving pressure in a fluid conduit that includes a cradle positioned in the relief valve conduit and having a ball support surface and a ball mounted on the ball support surface adapted for sealing against the valve seat of the pressure relief port. A spring supported surface and a spring positioned in the pressure relief conduit urges the cradle and the ball into sealing position against the valve seat of the pressure relief port.

We claim: 
     
         1 . A relief valve for relieving pressure in a fluid conduit, comprising:
 (a) a relief valve body in fluid communication with a fluid pressure system;   (b) a relief valve conduit formed in the relief valve body and having a valve seat positioned around a pressure relief port at one end of the conduit adapted for communication with the fluid pressure system and a discharge vent in an opposite end of the conduit;   (c) a cradle positioned in the relief valve conduit that includes:
 (i) a ball support surface and a ball positioned on the ball support surface, the ball is adapted for sealing against the valve seat of the pressure relief port; 
 (ii) a spring support surface; and 
 (iii) a plurality of spacers positioned between the ball support surface and spring support surface, the spacers form at least one flow port that permits fluid flow through and around the cradle; and 
   (d) a spring positioned adjacent the spring support surface and adapted to urge the cradle and the ball into sealing position against the valve seat of the pressure relief port when a predetermined load of the spring is not exceeded.   
     
     
         2 . The relief valve of  claim 1 , wherein the ball support surface of the cradle includes an annular segment corresponding in shape to a portion of the surface of the ball. 
     
     
         3 . The relief valve of  claim 1 , wherein the spring support surface comprises a planar surface defined by an inner and outer circumference of the cradle. 
     
     
         4 . The relief valve of  claim 1 , wherein the relief valve conduit includes a shoulder of reduced diameter for supporting an end of the spring remote from the ball. 
     
     
         5 . The relief valve of  claim 1 , wherein the ball comprises ethylene propylene diene monomer. 
     
     
         6 . The relief valve of  claim 5 , wherein the ball has a 70 Shore A hardness. 
     
     
         7 . The relief valve of  claim 1 , wherein the spring has a compression of about 50 percent between a free length and a fully compressed length. 
     
     
         8 . The relief valve of  claim 1 , wherein the spring is configured to compress when the predetermined load is exceeded thereby moving the ball out of sealing position against the valve seat of the pressure relief port to allow a discharge of fluid from the fluid pressure system. 
     
     
         9 . A water heater shutoff/thermal expansion control valve adapted for being positioned in flow communication with a water pressure system, and including pressure relief valve for relieving pressure in the system above a predetermined level, the pressure relief valve comprising:
 (a) a relief valve body adapted for fluid communication with a fluid pressure system;   (b) a relief valve conduit formed in the relief valve body and having a valve seat positioned around a pressure relief port at one end of the conduit adapted for communication with the fluid pressure system and a discharge vent in an opposite end of the conduit;   (c) a cradle positioned in the relief valve conduit that includes:
 (i) a ball support surface and a ball positioned on the ball support surface, the ball is adapted for sealing against the valve seat of the pressure relief port; 
 (ii) a spring support surface; and 
 (iii) a plurality of spacers positioned between the ball support surface and spring support surface, the spacers form at least one flow port that permits fluid flow through and around the cradle; and 
   (d) a spring positioned adjacent the spring support surface and adapted to urge the cradle and the ball into sealing position against the valve seat of the pressure relief port when a predetermined load of the spring is not exceeded.   
     
     
         10 . The water heater shutoff/thermal expansion control valve of  claim 9 , wherein the ball support surface of the cradle includes an annular segment corresponding in shape to a portion of the surface of the ball. 
     
     
         11 . The water heater shutoff/thermal expansion control valve of  claim 9 , wherein the spring support surface comprises a planar surface defined by an inner and outer circumference of the cradle. 
     
     
         12 . The water heater shutoff/thermal expansion control valve of  claim 9 , wherein the relief valve conduit includes a shoulder of reduced diameter for supporting an end of the spring remote from the ball. 
     
     
         13 . The water heater shutoff/thermal expansion control valve of  claim 9 , wherein the ball comprises ethylene propylene diene monomer. 
     
     
         14 . The water heater shutoff/thermal expansion control valve of  claim 9 , wherein the ball has a 70 Shore A hardness. 
     
     
         15 . The water heater shutoff/thermal expansion control valve of  claim 9 , wherein the spring is configured to compress when the predetermined load is exceeded thereby moving the ball out of sealing position against the valve seat of the pressure relief port to allow a discharge of fluid from the fluid pressure system.