Pilot-operated thermal expansion valve and adjustment method

Abstract

The present invention discloses a pilot-operated thermal expansion valve and a regulating method. The pilot-operated thermal expansion valve is an actuator that is controlled by a pressure and / or temperature signal and can implement automatic flow regulation and intelligent management. The pilot-operated thermal expansion valve can be applied to superheat control of various refrigeration systems such as air conditioning, freezing, and refrigeration. The pilot-operated thermal expansion valve is composed of a main valve part, a pilot valve part, and a driving part. The main valve part has a main valve body, a piston assembly, and a main valve partition. The driving part has a temperature-sensing package, a driving diaphragm, and a driving valve stem. The beneficial effects of the present invention are: it has the characteristics of simple structure, convenient manufacturing, and high cost performance.

Description

Technical Field

[0001] The invention relates to a thermal expansion valve, in particular to a pilot-operated thermal expansion valve and a regulating method. Background Art

[0002] At present, the thermal expansion valves on the market are basically direct-acting expansion valves, which control the expansion valve flow rate by moving the diaphragm. Due to the limitation of the diaphragm stroke, the expansion valve with a large flow rate has a small adjustment range and poor accuracy. Due to the widespread application of frequency conversion technology and unloading technology in refrigeration systems, higher requirements are placed on the adjustment range of expansion valves. In particular, large-capacity thermal expansion valves are almost blank in the market. In view of this, it is urgent to design a thermal expansion valve with a large adjustment range and high adjustment accuracy. Summary of the invention

[0003] The technical problem to be solved by the present invention is that the diaphragm stroke of the dynamic thermal expansion valve in the prior art is limited and cannot meet the requirements of large flow, and a new pilot thermal expansion valve and a regulating method are provided.

[0004] In order to achieve this purpose, the technical solution of the present invention is as follows: a pilot-operated thermal expansion valve comprises:

[0005] The main valve part comprises a main valve body, a piston assembly and a main valve partition. The main valve body comprises a main valve inlet at the left end, a main valve outlet at the right end and a main valve chamber in the middle. The main valve chamber extends in the left-right direction. The main valve chamber has a right opening and the main valve partition is arranged inside the right opening. The piston assembly comprises a piston body, a control valve core and a piston spring. The piston body is located inside the main valve chamber and shifts left and right along the main valve chamber. The inside of the main valve chamber is divided into a main valve left chamber and a main valve right chamber by the piston body. The main valve right chamber is connected to the main valve inlet through a connecting channel. The main valve partition is formed with A main valve port is connected to the main valve right chamber and the main valve outlet respectively, and a connecting hole is formed on the left wall of the main valve chamber to connect the main valve left chamber and the main valve inlet respectively. The piston spring is arranged inside the left chamber of the main valve, and the piston spring extends in the left-right direction. The left end of the piston spring is a fixed end, and the right end of the piston spring is a movable end. The right end of the piston spring abuts against the left side of the piston body. The piston spring is in a compressed state. The control valve core extends in the left-right direction. The control valve core has a valve core left section and a valve core right section. The left side of the valve core left section is fixedly connected to the right side of the piston body, and the valve core right section is inside the main valve port;

[0006] A pilot valve part, which has a pilot valve body, the pilot valve body has a pilot valve chamber, a pilot valve port is formed inside the pilot valve chamber, the pilot valve chamber is divided into a pilot valve upper chamber and a pilot valve lower chamber by the pilot valve port, the pilot valve upper chamber extends in the left-right direction, the right end of the pilot valve upper chamber has an external pressure interface, the pilot valve lower chamber is connected to the main valve left chamber through another connecting channel, the pilot valve lower chamber extends in the up-down direction, a conical valve core and a valve core spring are arranged inside the pilot valve lower chamber, the conical valve core is on the top, the valve core spring is on the bottom, the valve core spring extends in the up-down direction, the lower end of the valve core spring is a fixed end, the upper end of the valve core spring is a movable end, and the valve core spring is in a compressed state; and,

[0007] The driving part has a temperature-sensing bag, a driving diaphragm and a driving valve stem. The pressure above the driving diaphragm comes from the temperature-sensing bag, and the pressure below the driving diaphragm comes from the upper chamber of the pilot valve. The driving valve stem is arranged between the driving diaphragm and the conical valve core, and the three have a common axis.

[0008] As a preferred embodiment of the pilot-operated thermal expansion valve, the right section of the valve core is formed with a valve core side hole, and the valve core side hole has an opening formed on the outer peripheral surface of the right section of the valve core and an opening formed on the right side of the right section of the valve core; in an initial state, the right section of the valve core is completely located inside the main valve port, at which time the opening on the outer peripheral surface of the right section of the valve core of the valve core side hole is completely blocked by the main valve port, so that the fluid in the right chamber of the main valve cannot flow into the main valve outlet; if the piston body is moved to the left, the control valve core is synchronized and the opening on the outer peripheral surface of the right section of the valve core of the valve core side hole is gradually exposed to the right chamber of the main valve, at which time the fluid in the right chamber of the main valve can enter the main valve outlet through the valve core side hole.

[0009] As a preferred solution of the pilot-operated thermal expansion valve, the transverse cross-section of the valve core side hole is a triangular hole, a strip hole or a rectangular hole.

[0010] As a preferred embodiment of the pilot-operated thermal expansion valve, the outer diameter of the left section of the valve core is smaller than the outer diameter of the right section of the valve core, and there is a gap along the left-right direction between the right side of the piston body and the left side of the right section of the valve core. The piston assembly also has a sealing ring, and the sealing ring has an axial portion and a radial portion. The axial portion extends along the left-right direction and surrounds the piston body and the main valve chamber, and the radial portion extends inward from the right end of the axial portion to the inside of the gap.

[0011] The present invention also provides a method for adjusting a pilot-operated thermal expansion valve, comprising the following steps:

[0012] A pilot-operated thermal expansion valve is provided; and

[0013] The temperature signal of the control position is received through the temperature sensing package and / or the pressure signal of the control position is received through the external pressure interface to control the up and down displacement of the driving diaphragm so that the driving valve stem drives the conical valve core to move up and down to adjust the opening size of the pilot valve port, and then adjust the opening size of the main valve port.

[0014] Compared with the prior art, the beneficial effects of the present invention are at least that it has the characteristics of simple structure, convenient manufacturing and high cost performance.

[0015] In addition to the technical problems solved by the present invention, the technical features that constitute the technical solution, and the beneficial effects brought about by the technical features of the technical solution described above, other technical problems that can be solved by the present invention, other technical features included in the technical solution, and the beneficial effects brought about by these technical features will be further described in detail in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below by means of specific embodiments connected with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0018] See also Figure 1 , the figure shows a pilot-operated thermal expansion valve. The pilot-operated thermal expansion valve is an actuator that can implement automatic flow regulation and intelligent management controlled by pressure and / or temperature signals. The pilot-operated thermal expansion valve can be used for superheat control of various refrigeration systems such as air conditioning, freezing, and refrigeration.

[0019] The pilot-operated thermal expansion valve is composed of a main valve part 1, a pilot valve part 2 and a drive part 3.

[0020] The main valve part 1 includes a main valve body 11 , a piston assembly 12 and a main valve diaphragm 13 .

[0021] The main valve body 11 has a main valve inlet 111 at the left end, a main valve outlet 112 at the right end and a main valve chamber 113 in the middle. The pressure of the main valve inlet 111 is greater than the pressure of the main valve outlet 112. The main valve chamber 113 extends in the left-right direction. The main valve chamber 113 has a right opening 1130. The main valve partition 13 is arranged at the right opening 1130. The piston assembly 12 is accommodated in the main valve chamber 113. The piston assembly 12 has a piston body 121, a control valve core 122 and a piston spring 123. The piston body 121 can be displaced left and right along the main valve chamber 113. The inside of the main valve chamber 113 is divided into a main valve left chamber 1131 and a main valve right chamber 1132 by the piston body 121. The main valve right chamber 1132 is connected to the main valve inlet 111 through a connecting channel (not shown in the figure). The connecting passage may be formed in the wall of the main valve chamber 113. The main valve partition 13 is formed with a main valve port 130 respectively connected to the main valve right chamber 1132 and the main valve outlet 112. The left wall of the main valve chamber 113 is formed with a connecting hole 14 respectively connected to the main valve left chamber 1131 and the main valve inlet 111.

[0022] The piston spring 123 is arranged inside the left chamber 1131 of the main valve. The piston spring 123 extends in the left-right direction. The left end of the piston spring 123 is a fixed end. The left end of the piston spring 123 can be fixed on the left wall of the main valve chamber 113. The right end of the piston spring 123 is a movable end. The right end of the piston spring 123 is against the left side of the piston body 121. The piston spring 123 is in a compressed state. The piston spring 123 always provides a rightward force to the piston body 121.

[0023] The control valve core 122 extends left and right. Preferably, the control valve core 122 has a valve core left section 1121 and a valve core right section 1122. The outer diameter of the valve core left section 1121 is smaller than the outer diameter of the valve core right section 1122. The left side of the valve core left section 1121 is fixed to the right side of the piston body 121, so that the piston body 121 and the control valve core 122 can move synchronously. The valve core right section 1122 is placed inside the main valve port 130 and the two are matched with each other in the axial hole. The valve core right section 1122 is formed with a valve core side hole. The valve core side hole connects the opening formed on the outer peripheral surface of the valve core right section 1122 and the opening formed on the right side of the valve core right section 1122. In the initial state, under the action of the piston spring 123, the right section 1122 of the valve core is completely inside the main valve port 130. At this time, the opening of the outer peripheral surface of the right section 1122 of the valve core side hole is completely blocked by the main valve port 130, so that the fluid in the right chamber 1132 of the main valve cannot flow into the main valve outlet 112. If the piston body 121 is moved to the left, the control valve core 122 is synchronized and the valve core side hole is gradually exposed to the right chamber 1132 of the main valve. At this time, the fluid in the right chamber 1132 of the main valve can enter the main valve outlet 112 through the valve core side hole. The part of the valve core side hole exposed to the right chamber 1132 of the main valve, that is, the flow area of ​​the control valve core 122 and the main valve port 130, determines the flow rate of the thermal expansion valve. The larger the portion of the opening of the outer peripheral surface of the right section 1122 of the valve core side hole exposed to the right chamber 1132 of the main valve is, the larger the flow rate of the thermal expansion valve is. The valve core side hole can be designed in different shapes and sizes, so that different flow curves (for example, linear type, exponential curve type) can be obtained. The transverse cross section of the valve core side hole is a triangular hole, a strip hole or a rectangular hole, etc.

[0024] There is a gap in the left-right direction between the right side of the piston body 121 and the left side of the right section 1122 of the valve core. Preferably, the piston assembly 12 also has a sealing ring 124. The sealing ring 124 has an axial portion and a radial portion. The axial portion extends in the left-right direction and surrounds the piston body 121 and the main valve chamber 113. The radial portion extends inward from the right end of the axial portion to the inside of the gap. Move the piston body 121 to the right until the right side of the radial portion abuts against the left side of the main valve partition 13. At this time, the piston body 121 cannot move further to the right and the piston body 121 presses the radial portion to the right to further seal the main valve port to ensure that the main valve port is completely blocked and completely shut off.

[0025] The pilot valve part 2 has a pilot valve body 21. The pilot valve body 21 has a pilot valve chamber 210. A pilot valve port 22 is formed inside the pilot valve chamber 210. The pilot valve chamber 210 is divided into a pilot valve upper chamber 2101 and a pilot valve lower chamber 2102 by the pilot valve port 22. The pilot valve upper chamber 2101 extends in the left-right direction. The right end of the pilot valve upper chamber 2101 has an external pressure interface 23. The pilot valve lower chamber 2102 is connected to the main valve left chamber 1131 through a connecting channel 26. The connecting channel 26 can be formed in the wall of the main valve chamber 113. The pilot valve lower chamber 2102 extends in the up-down direction. A conical valve core 24 and a valve core spring 25 are arranged inside the pilot valve lower chamber 2102. The conical valve core 24 is on the top, and the valve core spring 25 is on the bottom. The valve core spring 25 extends in the up-down direction. The lower end of the valve core spring 25 is a fixed end. The upper end of the valve core spring 25 is a movable end. The valve core spring 25 is in a compressed state. The valve core spring 25 provides an upward force on the conical valve core 24, so that the conical valve core 24 can completely block the pilot valve port 22 without other external forces, that is, the gap formed by the conical valve core 24 and the pilot valve port 22 determines the flow rate of the pilot valve upper chamber 2101 and the main valve left chamber 1131, thereby determining the fluid pressure inside the main valve left chamber 1131.

[0026] The driving part 3 has a temperature sensing package 31, a driving diaphragm 32 and a driving valve stem 33. The driving diaphragm 32 is arranged on the top of the pilot valve body 21. The driving valve stem 33 is placed between the driving diaphragm 32 and the conical valve core 24. The driving diaphragm 32, the driving valve stem 33 and the conical valve core 24 have a common axis.

[0027] The pressure above the driving diaphragm 32 is controlled by the temperature-sensing package 31. The pressure below the driving diaphragm 32 is controlled by the pilot valve upper chamber 2101. The pilot valve upper chamber 2101 leads to the lower part of the driving diaphragm 32. The temperature signal of the control position is received through the temperature-sensing package 31 and / or the pressure signal of the control position (i.e., the external fluid) is received through the external pressure interface 23. The temperature change of the temperature-sensing package 31 and the pressure change in the pilot valve upper chamber 2101 will cause the driving diaphragm 32 to shift up and down, so as to drive the driving valve stem 33 to drive the tapered valve core 24 to shift up and down, so as to adjust the opening size of the pilot valve port 22.

[0028] By changing the position of the conical valve core 24, the flow area between the pilot valve upper chamber 2101 and the main valve left chamber 1131 can be controlled, so that the pressure in the main valve left chamber 1131 changes to change the position of the piston body 121, ultimately achieving the purpose of controlling the flow rate of the pilot thermal expansion valve.

[0029] The working principle of the pilot-operated thermal expansion valve is as follows:

[0030] In the initial state, the piston assembly 12 is in balance, that is, the leftward force provided by the main valve right chamber 1132 and the main valve outlet 112 to the piston assembly 12 is equal to the rightward force provided by the main valve left chamber 1131 and the piston spring 123 to the piston assembly 12. At the same time, the downward pressure of the driving diaphragm 32 (determined by the evaporation pressure of the liquid in the temperature-sensing package 316) is equal to the pressure from the upper chamber 2101 of the pilot valve below the driving diaphragm 32 and the upward force provided by the valve core spring 25.

[0031] When the temperature of the temperature-sensing package 316 decreases or the pressure of the pilot valve upper chamber 2101 increases (superheat decreases), the pressure above the driving diaphragm 32 decreases or the pressure below increases. The driving diaphragm 32 moves upward to drive the driving push rod to drive the conical valve core 24 to move upward. The opening of the pilot valve port 22 decreases, causing the pressure of the main valve left chamber 1131 to increase.

[0032] At this time, the leftward force of the piston assembly 12 remains unchanged while the rightward force is relatively reduced, so the piston assembly 12 moves rightward, and the opening of the main valve port decreases until the pressure downstream of the pilot thermal expansion valve decreases. That is, the pressure of the external pressure interface 23 decreases. The system regains balance while keeping the superheat basically unchanged.

[0033] On the contrary, when the temperature of the temperature-sensing package 316 increases or the pressure of the external pressure interface 23 decreases (superheat increases), the pressure above the driving diaphragm 32 increases or the pressure below decreases. The driving diaphragm 32 moves downward and drives the conical valve core 24 to move downward through the driving valve stem 33. The opening of the pilot valve port 22 increases, resulting in a decrease in the pressure of the left chamber 1131 of the main valve.

[0034] At this time, the leftward force of the piston assembly 12 remains unchanged while the rightward force increases relatively, so the piston assembly 12 moves leftward, and the opening of the main valve port increases until the pressure downstream of the pilot thermal expansion valve increases. That is, the pressure of the external pressure interface 23 increases. The system regains balance while keeping the superheat basically unchanged.

[0035] The above only expresses the implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. Pilot-operated thermal expansion valve, characterized in that: Contains: The main valve part comprises a main valve body, a piston assembly and a main valve partition. The main valve body comprises a main valve inlet at the left end, a main valve outlet at the right end and a main valve chamber in the middle. The main valve chamber extends in the left-right direction. The main valve chamber has a right opening and the main valve partition is arranged inside the right opening. The piston assembly comprises a piston body, a control valve core and a piston spring. The piston body is located inside the main valve chamber and shifts left and right along the main valve chamber. The inside of the main valve chamber is divided into a main valve left chamber and a main valve right chamber by the piston body. The main valve right chamber is connected to the main valve inlet through a connecting channel. The main valve partition is formed with A main valve port is connected to the main valve right chamber and the main valve outlet respectively, and a connecting hole is formed on the left wall of the main valve chamber to connect the main valve left chamber and the main valve inlet respectively. The piston spring is arranged inside the left chamber of the main valve, and the piston spring extends in the left-right direction. The left end of the piston spring is a fixed end, and the right end of the piston spring is a movable end. The right end of the piston spring abuts against the left side of the piston body. The piston spring is in a compressed state. The control valve core extends in the left-right direction. The control valve core has a valve core left section and a valve core right section. The left side of the valve core left section is fixedly connected to the right side of the piston body, and the valve core right section is inside the main valve port; A pilot valve part, which has a pilot valve body, the pilot valve body has a pilot valve chamber, a pilot valve port is formed inside the pilot valve chamber, the pilot valve chamber is divided into a pilot valve upper chamber and a pilot valve lower chamber by the pilot valve port, the pilot valve upper chamber extends in the left-right direction, the right end of the pilot valve upper chamber has an external pressure interface, the pilot valve lower chamber is connected to the main valve left chamber through another connecting channel, the pilot valve lower chamber extends in the up-down direction, a conical valve core and a valve core spring are arranged inside the pilot valve lower chamber, the conical valve core is on the top, the valve core spring is on the bottom, the valve core spring extends in the up-down direction, the lower end of the valve core spring is a fixed end, the upper end of the valve core spring is a movable end, and the valve core spring is in a compressed state; and, The driving part comprises a temperature-sensing package, a driving diaphragm and a driving valve stem. The pressure above the driving diaphragm comes from the temperature-sensing package, the pressure below the driving diaphragm comes from the upper chamber of the pilot valve, and the driving valve stem is arranged between the driving diaphragm and the conical valve core, and the three have a common axis. The right section of the valve core is formed with a valve core side hole, and the valve core side hole has an opening formed on the outer peripheral surface of the right section of the valve core and an opening formed on the right side of the right section of the valve core; in an initial state, the right section of the valve core is completely inside the main valve port, at this time, the opening of the outer peripheral surface of the right section of the valve core of the valve core side hole is completely blocked by the main valve port, so that the fluid in the right chamber of the main valve cannot flow into the main valve outlet; if the piston body is moved to the left, the control valve core is synchronized and the opening of the outer peripheral surface of the right section of the valve core of the valve core side hole is gradually blocked. The piston assembly is exposed to the right chamber of the main valve. At this time, the fluid in the right chamber of the main valve enters the main valve outlet through the valve core side hole; the outer diameter of the left section of the valve core is smaller than the outer diameter of the right section of the valve core, and there is a gap along the left-right direction between the right side of the piston body and the left side of the right section of the valve core. The piston assembly also has a sealing ring, and the sealing ring has an axial part and a radial part. The axial part extends along the left-right direction and surrounds the piston body and the main valve chamber, and the radial part extends inward from the right end of the axial part to the inside of the gap; The transverse cross section of the valve core side hole is a triangular hole or a rectangular hole.

2. The regulating method of the pilot-operated thermal expansion valve is characterized in that: It includes the following steps: Providing the pilot-operated thermal expansion valve according to claim 1; as well as, The temperature signal of the control position is received through the temperature sensing package and / or the pressure signal of the control position is received through the external pressure interface to control the up and down displacement of the driving diaphragm so that the driving valve stem drives the conical valve core to move up and down to adjust the opening size of the pilot valve port, and then adjust the opening size of the main valve port.

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