Refrigerating system and thermostatic expansion valve thereof

Abstract

A thermostatic expansion valve and a refrigerating system comprising the thermostatic expansion valve. The thermostatic expansion valve comprises a valve body arranged with an air box on the top, and the inner chamber of the air box is divided into an upper chamber and a lower chamber by a diaphragm. Within the inner chamber of the valve body there are provided a valve plug component and a valve port matched with the valve plug component. The inner chamber of the valve body is divided into a first interface chamber and a second interface chamber by a sealing line or sealing face between the valve port and the valve plug component. At the lower end part of the valve body there is provided a balance chamber to balance the valve plug component. The upper end part of the valve plug component is arranged within the lower chamber and the lower end part thereof is arranged within the balance chamber ( 14 ) of the valve body. The balance chamber is in communication with the lower chamber, and the balance chamber is in sealed isolation from both the first interface chamber and the second interface chamber. The structure of the thermostatic expansion valve is capable of reducing the systematic pressure difference to which the valve plug component is subjected, such that the regulating precision of the valve plug component is improved.

What is claimed is: 
     
         1 . A thermal expansion valve, comprising a valve body, wherein an air box is provided at an upper end of the valve body, an inner chamber of the air box is partitioned into an upper chamber and a lower camber by a diaphragm; a valve core component and a valve port fitted with the valve core component are provided in an inner chamber of the valve body, a lower end portion of the valve body is further provided with a balance chamber configured to balance the valve core component; an upper end portion of the valve core component is arranged in the lower chamber, and a lower end portion of the valve core component is arranged in the balance chamber of the valve body, and
 wherein the balance chamber communicates with the lower chamber, and is sealed to be isolated from the inner chamber of the valve body.   
     
     
         2 . The thermal expansion valve according to  claim 1 , wherein a projected area of an upper pressure-bearing surface, subjected to pressure in the lower chamber, of the upper end portion of the valve core component on a plane perpendicular to an axis of the valve core component is substantially equal to a projected area of a lower pressure-bearing surface, subjected to pressure in the balance chamber, of the lower end portion of the valve core component on a plane perpendicular to the axis of the valve core component. 
     
     
         3 . The thermal expansion valve according to claim  1 , wherein, when the valve core component and the valve port are closed, a sealing line or a sealing surface between the valve port and the valve core component partitions the inner chamber of the valve body into a first interface chamber and a second interface chamber and
 wherein a first pressure-bearing surface and a second pressure-bearing surface subjected to opposite forces are provided on a side wall of the valve core component in the first interface chamber.   
     
     
         4 . The thermal expansion valve according to  claim 3 , wherein a projected area of the first pressure-bearing surface on a plane perpendicular to the axis of the valve core component is substantially equal to a projected area of the second pressure-bearing surface on a plane perpendicular to the axis of the valve core component. 
     
     
         5 . The thermal expansion valve according to  claim 3 , wherein a third pressure-bearing surface and a fourth pressure-bearing surface subjected to opposite forces are provided on the side wall of the valve core component in the second interface chamber. 
     
     
         6 . The thermal expansion valve according to  claim 5 , wherein a projected area of the third pressure-bearing surface on a plane perpendicular to the axis of the valve core component is substantially equal to a projected area of the fourth pressure-bearing surface on a plane perpendicular to the axis of the valve core component. 
     
     
         7 . The thermal expansion valve according to claim  5 , wherein the valve core component is provided with an inclined sealing surface for sealing the valve port, and wherein
 when the valve core component and the valve port are closed, the sealing line between the valve core component and the valve port partitions the inclined sealing surface into the second pressure-bearing surface in the first interface chamber and the third pressure-bearing surface in the second interface chamber.   
     
     
         8 . The thermal expansion valve according to  claim 1 , wherein the balance chamber communicates with an outlet end of an evaporator. 
     
     
         9 . The thermal expansion valve according to  claim 8 , wherein the valve body is provided therein with a communicating hole communicating with the lower chamber, and the communicating hole communicates with the balance chamber via a first capillary arranged outside the valve body. 
     
     
         10 . The thermal expansion valve according to  claim 9 , wherein a side wall of the valve body is provided with a first mounting hole communicating with the communicating hole and a second mounting hole communicating with the balance chamber; one end of the first capillary is arranged in the first mounting hole, and the other end of the first capillary is arranged in the second mounting hole. 
     
     
         11 . The thermal expansion valve according to  claim 10 , wherein the air box comprises an air box base connected to the valve body, and
 wherein each of the first mounting hole and the second mounting hole is arranged obliquely such as to have a downward inner end and an upward outer end, no matter whether the air box base is positioned upwards or downwards.   
     
     
         12 . The thermal expansion valve according to  claim 11 , wherein an angle between an axis of the first mounting hole and an axis of the valve body is substantially equal to an angle between an axis of the second mounting hole and the axis of the valve body. 
     
     
         13 . The thermal expansion valve according to  claim 10 , wherein the air box comprises an air box base connected to the valve body, and wherein no matter whether the air box base is positioned upwards or downwards, the side wall of the valve body is provided thereon with an inclined surface having an inward upper end and an outward lower end, so that the first capillary lies against the inclined surface. 
     
     
         14 . The thermal expansion valve according to  claim 9 , wherein a capillary groove is provided in the side wall of the valve body, and the first capillary is arranged in the capillary groove. 
     
     
         15 . The thermal expansion valve according to  claim 9 , wherein a connecting hole is integrally formed and communicates with the communicating hole and is located below the communicating hole, and
 wherein the connecting hole directly communicates with the balance chamber.   
     
     
         16 . The thermal expansion valve according to  claim 1 , wherein the upper pressure-bearing surface of the valve core component is connected to a transmission piece with a clearance between the upper pressure-bearing surface and the transmission piece, the valve core component is provided with a valve core component through hole in the axial direction, and the lower chamber communicates with the balance chamber via the valve core component through hole. 
     
     
         17 . The thermal expansion valve according to  claim 1 , wherein an upper end portion of the valve body is provided with an annular chamber communicating with the lower chamber, and an elastic component is provided in the annular chamber, with a bottom end of the elastic component being supported on a bottom wall of the annular chamber or on a first spring seat, and a top end of the elastic component supporting a transmission piece connected to the valve core component. 
     
     
         18 . The thermal expansion valve according to  claim 17 , wherein the annular chamber further communicates with the balance chamber via the first capillary. 
     
     
         19 . The thermal expansion valve according to  claim 17 , wherein a guide component is provided outside of the valve core component and is arranged in the inner chamber of the lower end portion of the valve body, the balance chamber is sealed to be isolated from the second interface chamber by means of the guide component and a sealing member arranged on the guide component, an opening in a lower portion of the balance chamber is threadingly connected with a valve bonnet configured to support the guide component. 
     
     
         20 . The thermal expansion valve according to  claim 19 , wherein a clamping depression for being clamped by a clamping tool is provided on an external portion of the lower end portion of the valve core component in the balance chamber. 
     
     
         21 . A refrigerating system, comprising a compressor, an evaporator, a condenser, and the thermal expansion valve according to  claim 1 , wherein the upper chamber is connected to an outlet end of the evaporator via a temperature sensing component, and the lower chamber communicates with the outlet end of the evaporator via a balance tube.