Pneumatic system

Abstract

A pneumatic system includes a first line configured to be coupled to a container, and to convey a flow of gas from a source to the container, a second line in communication with gas in the container, a valve coupled in series with the first line, between the source and the container, and a spring member. The valve includes a body having a first port, a second port, and an exhaust port, and the valve includes a moveable element in communication with the second line and is configured to control the flow of gas through the first line as a function of the pressure of the gas within the container. The spring member is positioned to apply a biasing force to a first side of the moveable element, and the second line provides a feedback to a second side of the moveable element.

What is claimed is: 
     
         1 . A pneumatic system, comprising:
 a first line configured to be coupled to a container, and to convey a flow of gas from a source to the container;   a second line in communication with gas in the container;   a valve coupled in series with the first line, between the source and the container, wherein the valve comprises:
 a body having a first port, a second port, and an exhaust port; and 
 a moveable element operable within the body to selectively: limit the flow of gas through the first port, the second port, and the exhaust port; place the first port in fluid communication with the second port; and place the container in fluid communication with the exhaust port, 
 wherein the moveable element is in communication with the second line and is configured to control the flow of gas through the first line as a function of the pressure of the gas within the container; and 
   a spring member positioned to apply a biasing force to a first side of the moveable element, wherein the second line provides a feedback to a second side of the moveable element.   
     
     
         2 . The pneumatic system of  claim 1 , wherein the second line is narrower than the first line and extends within the first line. 
     
     
         3 . The pneumatic system of  claim 2 , wherein the second line is configured such that when the first line is coupled to the container, the second line is simultaneously placed in fluid communication with the gas in the container. 
     
     
         4 . The pneumatic system of  claim 3 , wherein the second line projects from an end of the first line such that when the first line is coupled to the container, the second line extends into the volume of the container. 
     
     
         5 . The pneumatic system of  claim 3 , wherein the second line is arranged co-axially with the first line. 
     
     
         6 . The pneumatic system of  claim 1 , wherein the moveable element comprises a valve gate. 
     
     
         7 . The pneumatic system of  claim 1 , wherein the valve controls the flow of gas through the first line as a function of a differential between the biasing force and the feedback. 
     
     
         8 . A pneumatic system for actively maintaining the pressure in a container, comprising:
 a container that defines an inner volume;   a source configured to provide a pressurized flow of gas to the container;   a first line having an end coupled to the container;   a second line having an end in fluid communication with the inner volume of the container;   a valve coupled to the first line, the second line, the source, and an exhaust, wherein the valve is selectively operable in a first state to place the source in fluid communication with the first line, a second state to close off the container from the source and the exhaust, and a third state to place the container in fluid communication with the exhaust; and   at least one of a spring member and a pressure regulator configured to apply a force that biases the valve into the first state, wherein the second line provides a feedback that actuates the valve into the second state or the third state based on the pressure in the container.   
     
     
         9 . The pneumatic system of  claim 8 , wherein the valve is coupled in series with the first line, between the source and the container. 
     
     
         10 . The pneumatic system of  claim 9 , wherein the second line is narrower than the first line and extends within the first line. 
     
     
         11 . The pneumatic system of  claim 10 , wherein the second line is configured such that when the first line is coupled to the container, the second line is simultaneously placed in fluid communication with the gas in the container. 
     
     
         12 . The pneumatic system of  claim 11 , wherein the second line projects from the end of the first line such that when the first line is coupled to the container, the second line extends into the volume of the container. 
     
     
         13 . The pneumatic system of  claim 11 , wherein the second line is arranged co-axially with the first line. 
     
     
         14 . The pneumatic system of  claim 8 , wherein the feedback actuates the valve into the second state when the pressure in the container reaches a desired pressure level. 
     
     
         15 . The pneumatic system of  claim 14 , wherein the feedback actuates the valve into the third state when the pressure in the container rises above the desired pressure level. 
     
     
         16 . The pneumatic system of  claim 8 , wherein the feedback actuates the valve into the second state when the pressure in the container reaches a desired pressure range. 
     
     
         17 . The pneumatic system of  claim 16 , wherein the feedback actuates the valve into the third state when the pressure in the container rises above the desired pressure range. 
     
     
         18 . A method of maintaining pressure within a container, comprising:
 coupling a container to a source of pressurized gas with a first line;   placing a second line in fluid communication with an inner volume of the container; and   regulating the pressure within the container with a pneumatic system, the pneumatic system comprising:   a valve coupled to the first line, the second line, the source of pressurized gas, and an exhaust, wherein the valve is selectively operable in a first state to place the source of pressurized gas in fluid communication with the first line, a second state to close off the container from the source of pressurized gas and the exhaust, and a third state to place the container in fluid communication with the exhaust; and   at least one of a spring member and a pressure regulator configured to apply a force that biases the valve into the first state, wherein the second line provides a feedback that actuates the valve into the second state or the third state based on the pressure in the container.   
     
     
         19 . The method of  claim 18 , wherein the second line is configured such that when the first line is coupled to the container, the second line is simultaneously placed in fluid communication with the gas in the container. 
     
     
         20 . The method of  claim 19 , further comprising adjusting the at least one of the spring member and the pressure regulator to adjust the force that biases the valve into the first state.