Pressure tank

Abstract

A pressure tank includes a metallic vessel, a plastic liner received in the metallic vessel, a flexible diaphragm, two connectors and a nozzle coupled to the nipples respectively. The metallic vessel includes upper and lower shells. The upper shell defines a first planar area on a side thereof and a second planar area on a top thereof. The lower shell defines a third planar area therebottom. The flexible diaphragm divides the metallic vessel into a storage space and a pneumatic room. Each of the connectors includes a nipple and an anti-leak assembly. The nipples of the connectors are mounted on the side and top of the upper shell respectively and are in communication with the storage space. The two anti-leak assemblies provide leakproof connection between the nipples and the plastic liner. Additionally, the nozzle is mounted on the third planar area to be in communication with the pneumatic room.

The invention claimed is: 
     
         1 . A pressure tank, comprising a metallic vessel, a plastic liner enclosed by the metallic vessel, and a through-wall connector mounted on the metallic vessel, wherein the through-wall connector includes:
 a tubular body having an inner tubular portion which passes through the metallic vessel and the plastic liner, and has a neck section at an end thereof;   a washer placed around the tubular body and sandwiched in between the metallic vessel and the plastic liner;   a retainer ring placed around the inner tubular portion of the tubular body and having a flat annular disk, a circumferential wall extending outward from an outer periphery of the flat annular disk, and a flat ring flange extending outward from a peripheral end of the circumferential wall and being in contact with the plastic liner, wherein the retainer ring, the plastic liner and the inner tubular portion co-define an accommodation, and   an O-ring placed around the inner tubular portion of the tubular body, received in the accommodation, and sandwiched in between the retainer ring and the plastic liner, the O-ring having a first peripheral area contacting with plastic liner, a second peripheral area contacting with the circumferential wall of the retainer ring and a third peripheral area contacting with the flat annular disk of the retainer ring;   wherein the neck section of the inner tubular portion of the tubular body is bent to hold the flat annular disk of the retainer ring.   
     
     
         2 . The pressure tank of  claim 1 , wherein the circumferential wall of the retainer ring extends obliquely outward from the flat annular disk, and a portion of the circumferential wall between the circumferential wall and the flat annular disk is arc-shaped. 
     
     
         3 . The pressure tank of  claim 2 , wherein the circumferential wall of the retainer ring extends obliquely outward to the flat ring flange, and a portion of the circumferential wall between the circumferential wall and the flat ring flange is arc-shaped. 
     
     
         4 . The pressure tank of  claim 1 , wherein the metallic vessel includes an upper shell and a lower shell which are joined together, the plastic liner is received in the upper shell of the metallic vessel, the upper shell of the metallic vessel has a circular plate and a hollow cylinder extending from the periphery of the circular plate, and the through-wall connector is secured on the hollow cylinder of the upper shell. 
     
     
         5 . The pressure tank of  claim 4 , wherein the hollow cylinder of the upper shell of the metallic vessel defines a recessed first planar area where the through-wall connector is welded. 
     
     
         6 . The pressure tank of  claim 4  further including a diaphragm disposed in the plastic liner, and a nozzle secured on the lower shell of the metallic vessel; wherein the plastic liner and the diaphragm together define a storage space therebetween; the diagram and the lower shell together define a pneumatic room therebetween; the through-wall connector is in communication with the storage space; and the nozzle is in communication with the pneumatic room. 
     
     
         7 . The pressure tank of  claim 1 , wherein the tubular body of the through-wall connector further includes an exposed tubular portion that has a polygonal section and a cylindrical section, wherein the cylindrical section extends from the polygonal section and is weld to the metallic vessel. 
     
     
         8 . The pressure tank of  claim 7 , wherein the cylindrical section has a diameter smaller than that of the polygonal section.