Liquid storage tank

Abstract

A liquid storage tank includes a housing, a piston, a lower cover, an elastic element, and an outlet pipe. The piston is located in the housing. The lower cover is attached to the housing and has a support post extending toward the piston. The piston, the housing, and the lower cover define a tank chamber. The elastic element is connected with the tank hosing and the piston. The outlet pipe communicates with the tank chamber.

What is claimed is: 
     
         1 . A liquid storage tank, comprising:
 a housing;   a piston in the housing;   a lower cover attached to the housing and comprising a support post that extends toward the piston, wherein the piston, the housing, and the lower cover define a tank chamber;   an elastic element connected with the housing and the piston; and   an outlet pipe communicating with the tank chamber.   
     
     
         2 . The liquid storage tank of  claim 1 , wherein a length of the support post is greater than a distance between the outlet pipe and the lower cover. 
     
     
         3 . The liquid storage tank of  claim 1 , wherein the housing further comprises a column, the piston further comprises a rod, and two ends of the elastic element are connected with the column and the rod, respectively. 
     
     
         4 . The liquid storage tank of  claim 1 , further comprising:
 an inlet pipe communicating with the tank chamber.   
     
     
         5 . The liquid storage tank of  claim 1 , wherein the housing further comprises an upper portion opposite to the lower cover, and the upper portion has an air vent therein. 
     
     
         6 . The liquid storage tank of  claim 1 , wherein the lower cover and the housing each comprises a screw thread, and the two screw threads are engaged with each other. 
     
     
         7 . The liquid storage tank of  claim 1 , further comprising:
 an o ring surrounding the piston and located between the housing and the piston.   
     
     
         8 . A liquid storage tank, comprising:
 a housing;   a lower cover attached to the housing;   a piston in the housing and comprising a support post that extends toward the lower cover, wherein the piston, the housing, and the lower cover define a tank chamber;   an elastic element connected with the housing and the piston; and   an outlet pipe communicating with the tank chamber.   
     
     
         9 . The liquid storage tank of  claim 8 , wherein the outlet pipe is connected with a sidewall of the housing. 
     
     
         10 . The liquid storage tank of  claim 1 , wherein a length of the support post is greater than a distance between the outlet pipe and the lower cover. 
     
     
         11 . The liquid storage tank of  claim 8 , wherein the outlet pipe is connected with the lower cover. 
     
     
         12 . The liquid storage tank of  claim 8 , wherein the lower cover and the housing each comprises a screw thread, and the two screw threads are engaged with each other. 
     
     
         13 . The liquid storage tank of  claim 8 , further comprising:
 a retaining element passing through the lower cover and fixed to the housing.   
     
     
         14 . A liquid storage tank, comprising:
 a housing comprising a protrusion;   a lower cover attached to the housing;   a piston in the housing, wherein the piston, the housing, and the lower cover define a tank chamber;   an elastic element connected with the housing and the piston; and   an outlet pipe communicating with the tank chamber.   
     
     
         15 . The liquid storage tank of  claim 14 , wherein a distance between the protrusion and the lower cover is greater than a distance between the lower cover and the outlet pipe. 
     
     
         16 . The liquid storage tank of  claim 14 , wherein the lower cover and the housing each comprises a screw thread, and the two screw threads are engaged with each other. 
     
     
         17 . The liquid storage tank of  claim 14 , further comprising:
 a retaining element passing through the lower cover and fixed to the housing.   
     
     
         18 . A liquid storage tank, comprising:
 a housing;   a lower cover attached to the housing;   a piston in the housing, wherein the piston, the housing, and the lower cover define a tank chamber;   an elastic element connected with the housing and the piston, wherein when the elastic element is not compressed, a distance between the piston and the lower cover is greater than a distance between the lower cover and the outlet pipe; and   an outlet pipe communicating with the tank chamber.   
     
     
         19 . The liquid storage tank of  claim 18 , wherein the housing further comprises a column, the piston further comprises a rod, and two ends of the elastic element are connected with the column and the rod, respectively. 
     
     
         20 . The liquid storage tank of  claim 18 , wherein the lower cover and the housing each comprises a screw thread, and the two screw threads are engaged with each other.