Patent Publication Number: US-2020300379-A1

Title: Gas valve

Description:
TECHNOLOGICAL FIELD 
     This disclosure concerns a gas valve, particularly suitable for use in a water carbonation system or appliance; and also concerns a system or appliance comprising such a valve. 
     BACKGROUND ART 
     References considered to be relevant as background to the presently disclosed subject matter are listed below:
         PCT application publication no. WO 2014/041539   PCT application publication no. WO 2015/118523   PCT application no. PCT/IL2017/051107   PCT application publication WO 2017/134014   U.S. Pat. No. 4,818,444   US 2005/0034758   US 2012/0111433       

     Acknowledgement of the above references herein is not to be inferred as meaning that these are in any way relevant to the patentability of the presently disclosed subject matter. 
     BACKGROUND 
     Systems and appliances for preparation of carbonated beverages are known, for example from WO 2014/041539, WO 2015/118523, and PCT/IL2017/051107. These PCT applications disclose on-demand carbonation systems that make use of carbon dioxide gas and liquid that are simultaneously fed into a carbonation chamber to thereby produce a carbonated beverage. Both feeds need to be activated or deactivated simultaneously. 
     GENERAL DESCRIPTION 
     Provided by this disclosure is a gas valve that operates to permit gas flow concurrently with a change of liquid flow dynamic in a liquid flow system. A particular use of the gas valve is in water carbonation systems and appliances for on demand preparation of a carbonated water-based beverage. The gas valve of this disclosure operates to permit gas flow upon water flow induction and the water flow and the gas flow may be combined, in a carbonation unit, for the preparation of said beverage. 
     Also provided by this disclosure is a water carbonation system comprising such a gas valve. 
     The gas valve comprises a gas passage, a piston mechanism and a liquid chamber in communication with a liquid flow duct. The gas passage is defined between a gas inlet port and a gas outlet port and comprises a valve unit switchable between a gas flow-arresting state and a gas flow permitting state, permitting gas flow from the inlet port to the outlet port. The piston mechanism comprises a piston member coupled to the valve unit and configured, through axial displacement of the piston member between first and second positions, to induce the valve unit to respectively switch between its gas flow-arresting state and a gas flow permitting state. As the liquid chamber is in communication with said duct, change in liquid pressure in said flow duct or change in the liquid flow dynamics through said duct induces a change in static pressure within the liquid chamber to thereby induce displacement of the piston. Such displacement then causes a respective switch of the valve unit to thereby permit gas flow through said gas passage concurrently with the water flow. 
     By one embodiment, the piston mechanism comprises a flexible liquid-impermeable diaphragm separating between the piston member and the liquid chamber and coupled to the piston member such that deformation of the diaphragm induces displacement of the piston member. 
     The valve unit may comprise a valve plunger that is disposed in a valve seat, the plunger being coupled to the piston member such that its switch between the gas flow-arresting state and the gas flow permitting state is through axial movement. The piston member and the valve plunger are typically coupled to one another in a fixed manner such that axial displacement of the piston member causes a concomitant axial displacement of the valve plunger. 
     The gas valve is typically configured such that an increase in static pressure within the liquid chamber induces the displacement of the piston member from the first to the second position. The piston member may be biased into its first position by a biasing arrangement and the displacement into the second position is against such bias. 
     Notwithstanding the typical configuration noted in the previous paragraph, the piston member may also be configured for displacement into its second position by a decrease in static pressure within said liquid chamber. A decrease in static pressure may occur in the case where the duct is in direct communication with a liquid source and accordingly the steady-state pressure within said chamber is essentially that of the source. When water is permitted to flow, through a downstream valve, the increase in flow causes a drop in static pressure in the duct and hence also in said chamber. The pressure decrease-induced piston member displacement will then cause the corresponding switch in the valve plunger. 
     It is of note that once gas flow is permitted by the valve, pressurized gas flows from the pressurized (e.g. CO 2 ) source towards the gas outlet port for its utilization by an appliance associated with or connected to the valve. As the gas is typically stored within the gas source (e.g. a pressurized gas container) at a relatively high pressure, gas flow through the valve typically causes abrupt reduction in the pressure, and hence abrupt expansion of the gas. Such expansion is typically endothermic, and hence is accompanied by a temperature drop at the gas outlet port. In order to minimize or prevent formation of water condensate or ice at the gas outlet port, the valve may, by an embodiment, further comprise a freezing-preventing module fitted at or associated with the gas outlet port. Such a freezing-preventing module is typically made of a material having a high heat conductivity, such as an metal or an alloy, and is typically designed to have a large surface area, e.g. porous, thus disrupting the flow of gas through the gas outlet port, thus reducing the rate of gas expansion and preventing formation of condensate. 
     By another aspect of this disclosure, there is provided a gas valve that comprises a gas passage defined between a gas inlet port and a gas outlet port and comprising a valve unit disposed between the gas inlet port and gas outlet port and switchable between a gas flow-arresting state and a gas flow permitting state, permitting gas flow from the inlet port to the outlet port; a piston mechanism comprising a piston member coupled to the valve unit and configured, through axial displacement of the piston member between first and second positions, to induce the valve unit to respectively switch between its gas flow-arresting state and a gas flow permitting state; a liquid chamber in communication with a liquid flow duct such that a change in liquid pressure in said flow duct or liquid flow dynamics through said duct induces a change in static pressure within the liquid chamber to thereby induce displacement of the piston, the piston mechanism further comprises a flexible liquid-impermeable diaphragm separating between the piston member and the liquid chamber and coupled to the piston member, increase in the static pressure within the liquid chamber causes deformation of the diaphragm to induces displacement of the piston from the first to the second position, and hence cause the valve unit to switch from gas flow-arresting state to said gas flow-permitting state. 
     Provided by this disclosure is also a water carbonation system that comprises a water flow system between a water source and a carbonation unit, a gas flow system between a pressurized carbon-dioxide source and the carbonation unit in which the water and the carbon-dioxide are combined to produce carbonated water; and a gas valve of the kind described above. The liquid duct of said valve is disposed in and constitutes a part of the water flow system to channel water flow from the source to the carbonation unit to flow through said duct. The gas passage of said valve is disposed in and constitutes a part of the gas flow system, such that carbon dioxide flows from the source to the carbonation unit through said gas passage. Water flow through said duct induces a change in static pressure within the liquid chamber to thereby induce displacement of the piston to permit gas flow into the carbonation unit concurrently with the flow of water. 
     The carbonation system typically comprises a liquid flow control valve upstream in the water flow system to said liquid duct, whereby opening of the valve to permit water flow through said duct increased static pressure within the water chamber to thereby cause the piston to displace from its first to its second position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 
         FIG. 1A  shows a schematic cross-section through a gas valve according to an embodiment of this disclosure, in a gas flow-arresting state. 
         FIG. 1B  shows a schematic cross-section through a gas valve according to another embodiment of this disclosure, in a gas flow-arresting state 
         FIG. 2  shows a schematic cross-section of the gas valve of  FIG. 1A  in a gas flow-permitting state. 
         FIG. 3  shows a schematic cross-section through a gas valve according to an embodiment of this disclosure that includes a module for preventing ice formation due to expansion of the gas at the gas outlet of the valve. 
         FIG. 4  is a block diagram of carbonation system embodying a valve of the kind shown in  FIGS. 1-3 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     In the following description the invention will be illustrated with some details in reference to specific embodiments of a gas valve that illustrates the features of this disclosure. This illustration is exemplary and non-limiting of the disclosure in its full scope as described. 
     In the following for sake of convenience the gas valve described in  FIGS. 1 and 2  will be described in reference to an upward-downward orientation. Direction towards the bottom of the figure will be regarded as “downward” and direction towards the top of the figure will be regarded as “upward”. Similarly, the respective top and bottom portions of the figure will be related to as such. This, as may be appreciated, does not necessarily have any functional significance and in actual use the valve may have a different orientation, e.g. it may be reversed, laterally rotated, etc. 
     Gas valve  10  shown in  FIG. 1A  includes a gas passage  12  defined between a gas inlet port  14  and a gas outlet port  16  and comprising a valve unit  18 . The valve unit  18  comprises a piston mechanism  20  with a piston member  22  coupled to the valve unit through coupling member  24  that is fixedly associated with a valve plunger  26 . In another configuration, shown in  FIG. 1B , the coupling member  24  is an integral part of piston member  22 . Consequently, through axial displacement of the piston member in a direction represented by arrow  28  between a first position shown in  FIG. 1A  and a second position shown in  FIG. 2  (see below), it induces a corresponding axial displacement of the valve plunger to induce the valve unit to switch from its gas flow-arresting state shown in  FIGS. 1A-1B  into the gas flow-permitting state shown in  FIG. 2 , and vice versa. 
     The piston member  22  is associated with a flexible diaphragm  30  that is liquid-impermeable and tightly anchored to the side walls  32  of piston chamber  34  though an anchoring skirt  36 . Diaphragm  30  separates between the piston member  22  and a liquid chamber  38  which is in communication through aperture  40  with liquid flow duct  42 . In the liquid flow duct  42 , water flows in an upstream-downstream, as represented by arrow  44 . When an upstream valve (not shown) is opened, water is induced to flow (in the direction of arrow  44 ); this increase in flow causes increase in pressure in the liquid chamber  38 . 
     Piston member  22  is associated with a biasing spring  46 , that induces an upward bias onto the piston member, namely towards the chamber  38 . Upon increase in pressure in chamber  38 , there is a downward pressure on the diaphragm, represented by arrow  48 , causing the diaphragm  30  and the associated piston member  22  to displace to the piston&#39;s second position shown in  FIG. 2 , whereupon the bottom face  50  of the piston member  22  rests against the bottom face  52  of the piston chamber  34 . 
     Valve plunger  26  comprises O-rings  54  which in the gas flow-arresting state seen in  FIGS. 1A-1B  blocks passage of gas between the gas inlet port and the gas outlet port along a gas flow represented by curved arrow  56 , which would occur without the valve. However, once the piston downwardly axial displaces in the second position shown in  FIG. 2 , the O-rings  54  are decoupled from valve seat  58  and gas flow in the general direction of arrow  56  is permitted. When the valve is shut, and there is no water flow in the duct, the pressure in chamber  38  is reduced and the piston member  22  is axially displaced to its first position shown in  FIGS. 1A-1B , causing concomitant axial displacement of the valve plunger  26  into the flow-arresting state seen in  FIGS. 1A-1B . 
     In the embodiment of  FIG. 3 , the gas outlet port  16  includes an anti-freeze module  60 , fitted within the gas outlet port, that is configured to disrupt the flow of gas through the outlet, and hence reduce the rate of expansion of the gas. Such module functions to minimize or prevent formation of a condensate that may form at the gas outlet due to the rapid expansion of the pressurized gas once gas flow is permitted through the gas outlet. Anti-freeze module  60  may typically comprise a porous structure that is made of a high heat conducting material, e.g. a metal or an alloy. 
       FIG. 4  is an overall schematic representation of some elements of a carbonation system  100  employing the valve of the kind seen in  FIGS. 1-3 . The system comprises a water flow system  102  between a water source  104  and a carbonation unit  106 , while said liquid duct  42  is disposed in and constitutes part of this flow system, thus water that flows from the source  104  to the carbonation unit  106  passes through duct  42  of gas valve  10 . System  100  also comprises a gas flow system  110  between a gas source  112  and the carbonation unit  106 , and the gas passage  12  being disposed in and constitutes part of the gas flow system, such that carbon dioxide flows from the source to the carbonation unit through the gas passage. Water flow in water flow system  102  is controlled by means of valve  114 , and once flow of water is activated, this induces a concomitant gas flow in the gas flow system  110  in a manner described above. The concomitant flow of carbon dioxide and water into the carbonation unit  106  generates carbonated water which can be dispensed through dispensing outlet  120 .