Check Valve for Abrasive Blaster Pressure Vessel
A check valve is installed in the pressure flow line of an abrasive blaster of the type having a pop-up valve which opens under pressure and closes when depressurized to a predetermined level. The check valve is upstream of the pop-up valve and includes a having a valve chamber in communication with the pressure system for seating a valve mechanism adapted for opening and closing the valve chamber in response to the pressure level in the pressure system for closing the pressure system to back flow when the pressure in the system reaches a predetermined level.
1 . A check valve for a pressure system for pressurizing the pressure chamber of an abrasive blaster of the type having a pop-up valve which opens under pressure and closes when depressurized to a predetermined level, the check valve being positioned in the pressure system upstream of the pop-up valve, the check valve comprising:
a. a valve body having a valve chamber in communication with the pressure system for seating a valve mechanism; and
b. a valve mechanism seated in the valve chamber and adapted for opening and closing the valve chamber in response to the pressure level in the pressure system for closing the pressure system to back flow when the pressure in the system reaches a predetermined level.
2 . The check valve of claim 1 , further including a bleed hole in the valve body which is always open.
3 . The check valve of claim 1 , wherein the valve mechanism is a ball valve and the valve body includes a ball seat.
4 . The check valve of claim 3 , further including a biasing system for normally biasing the ball valve into closing engagement with the ball seat.
5 . The check valve of claim 4 , wherein the valve body includes a central bore and wherein the valve seat is in communication with the central bore, the check valve further including a retainer downstream of the ball valve for maintaining the ball valve in the valve body during operation.
6 . The check valve of claim 4 , wherein the cross-sectional area of the bleed hole is smaller than the cross-sectional area of the central bore.
7 . The check valve of claim 6 , wherein the cross-sectional area of the bleed hole is approximately 1/100 the cross-sectional area of the central bore.
8 . A ball check valve for a pressure system for pressurizing the pressure chamber of an abrasive blaster of the type having a pop-up valve which opens under pressure and closes when depressurized to a predetermined level, the ball check valve being positioned in the pressure system upstream of the pop-up valve, the ball check valve further having a central bore therethrough in communication with the pressure stream in the system, the ball check valve comprising:
a. a valve body having a chamber including a ball seat
b. a ball valve mechanism seated in the valve chamber and adapted for opening and closing the valve chamber in response to the pressure level in the pressure system for closing the pressure system to back flow when the pressure in the system reaches a predetermined level;
c. a bleed hole in the valve body which is always open; and
d. a retainer in the valve body for retaining the ball valve mechanism in the chamber during operation.
9 . The ball check valve of claim 8 , further including a biasing system for normally biasing the ball valve mechanism into closing engagement with the ball seat.
10 . The ball check valve of claim 8 , wherein the cross-sectional area of the bleed hole is smaller than the cross-sectional area of the central bore.
11 . The ball check valve of claim 10 , wherein the cross-sectional area of the bleed hole is approximately 1/100 the cross-sectional area of the central bore.