A temperature control valve driven by a shape memory alloy and its method

Abstract

The present invention discloses a temperature control valve driven by a shape memory alloy and a method thereof. The temperature control valve comprises a valve body, a spherical valve core, a valve stem and a spring holder; a driving coiled spring capable of driving the valve stem to rotate through temperature change is sleeved on the lower part of the valve stem; the driving coiled spring is made of a shape memory alloy with a two-way memory effect and is not in contact with the inner wall of the valve body in a fully relaxed state; the valve stem above the driving coiled spring is connected with the spherical valve core, heat fluid inlet holes and cold fluid inlet holes are formed in the side wall of the spherical valve core, and a mixed fluid outlet hole communicated with a mixed fluid outlet is formed in the bottom; by driving the spherical valve core to rotate through the valve stem, the communication degrees between the heat fluid inlet holes and a heat fluid inlet, and between the cold fluid inlet holes and a cold fluid inlet can be respectively adjusted to control the temperature of the mixed fluid flowing out from the mixed fluid outlet. The design of the present invention is reasonable, and it has the characteristics of simple structure, continuous drainage, fast heat response speed, stable flow rate, long service life and easy installation and maintenance.

Description

Technical Field

[0001] The present invention relates to the technical field of valves, and particularly to a temperature control valve driven by a shape memory alloy and a method thereof. Background Art

[0002] A temperature control valve is an ideal control valve that can automatically sense and complete the medium temperature regulation without external energy and power. Its basic principle is: by controlling the inlet flow rate of the primary heat (cold) medium of heat exchangers, air conditioning units or other heat-using and cold-using equipment, to achieve the purpose of controlling the outlet temperature of the equipment. The temperature control valve can minimize the heat loss of the medium during pipeline transportation and achieve the constant temperature control of the medium. It can not only achieve energy-saving effects but also improve the comfort of users.

[0003] Temperature control valves can be divided into self-acting type and electric control type. Self-acting temperature control valves mainly use the principle of thermal expansion and contraction to achieve proportional regulation of the valve core, and automatically balance the flow rates of the refrigerant and the heat medium in a very short time to maintain the stability of the equipment outlet temperature. They have the advantages of simple installation, no need for external energy, and stable performance. Common temperature control valve cores include paraffin temperature control element valve cores and shape memory alloy spring valve cores. The paraffin temperature control element is to fill a mixture of paraffin and copper powder with different ratios into a temperature-sensitive package with good heat transfer performance. After sensing the temperature change, the volume of the paraffin changes, and then the diaphragm at the mouth of the temperature-sensitive package drives the spring to push the piston to adjust the flow rate. The shape memory alloy temperature-sensitive element is to sense the temperature change through the shape memory alloy spring and then change its own length and force value to push the valve core to adjust the temperature and flow rate. Among them, the shape memory alloy refers to a material composed of two or more metal elements that has a shape memory effect through thermoelastic and martensitic phase transformations and their inversions. Shape memory alloys can be divided into single-pass memory effect alloys, double-pass memory effect alloys, and full-range memory effect alloys according to the memory effect. The shape memory alloy with a double-pass memory effect means that the alloy restores its high-temperature phase shape when heated and its low-temperature phase shape when cooled. Compared with the paraffin-type temperature control valve, the shape memory alloy-type temperature control valve has a faster response speed, a longer service life, and a larger temperature selection range. At present, the shape memory alloy-type temperature control valve has been widely used.

[0004] However, the existing shape memory alloy-type temperature control valves only use the shape memory alloy to replace the original paraffin temperature-sensitive package, so its driving type is only linear. This limits the use of shape memory alloys in angular travel valves. Therefore, based on the characteristics of shape memory alloys, it is of great significance to study the application of more driving methods of shape memory alloys in temperature control. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides a temperature control valve and method driven by a shape memory alloy. Among them, the specific driving mode of the temperature control valve is that a driving coil spring made of a shape memory alloy outputs torque to the valve stem, driving the spherical valve core to rotate to change the flow rate of the hot and cold media, so as to achieve the purpose of temperature control. The temperature control valve has the advantages of simple structure, continuous drainage, fast heat response speed, stable flow rate, long service life, and large driving stroke.

[0006] The specific technical solutions adopted by the present invention are as follows:

[0007] In the first aspect, the present invention provides a temperature control valve driven by a shape memory alloy, including a valve body, a spherical valve core, a valve stem, and a spring holder; a hot fluid inlet and a cold fluid inlet are provided on the side wall of the valve body, a mixed fluid outlet is provided at the bottom, and a rotatable valve stem is provided inside; the upper part of the valve stem passes through the valve body, and a driving coil spring capable of driving the valve stem to rotate through temperature change is sleeved on the lower part; the driving coil spring is made of a shape memory alloy with a two-way memory effect and does not contact the inner wall of the valve body in the fully relaxed state; the valve stem above the driving coil spring is connected to the spherical valve core, and the spherical valve core is located inside the valve body; a hot fluid inlet hole and a cold fluid inlet hole are provided on the side wall of the spherical valve core, and a mixed fluid outlet hole communicating with the mixed fluid outlet is provided at the bottom; by driving the spherical valve core to rotate through the valve stem, the communication degrees between the hot fluid inlet hole and the hot fluid inlet, and between the cold fluid inlet hole and the cold fluid inlet can be adjusted respectively to control the temperature of the mixed fluid flowing out from the mixed fluid outlet.

[0008] Preferably, the cross-sectional diameter of the driving coil spring in the fully relaxed state is slightly smaller than the inner diameter of the valve body at the location where it is located.

[0009] Preferably, the connection between the valve stem and the top of the valve body has airtightness.

[0010] Preferably, the included angle between the center line connecting the center of the hot fluid inlet hole and the center of the cold fluid inlet hole and the center of the spherical valve core is 90°, and the hot fluid inlet and the cold fluid inlet are respectively located on opposite sides of the valve body; the inner diameters of the hot fluid inlet hole and the hot fluid inlet are equal, and the inner diameters of the cold fluid inlet hole and the cold fluid inlet are equal; the spherical valve core can rotate between a first limit position and a second limit position to adjust the flow rates of the hot fluid and the cold fluid: in the first limit position, the hot fluid inlet hole is directly opposite to the hot fluid inlet, the cold fluid inlet hole is closed by the inner wall of the valve body, and only the hot fluid enters the spherical valve core; in the second limit position, the cold fluid inlet hole is directly opposite to the cold fluid inlet, the hot fluid inlet hole is closed by the inner wall of the valve body, and only the cold fluid enters the spherical valve core.

[0011] Preferably, the inner diameter of the mixed fluid outlet hole is equal to that of the mixed fluid outlet, and it is directly opposite to the mixed fluid outlet.

[0012] Preferably, a vertically arranged baffle is connected to the valve stem located in the inner cavity of the spherical valve core; the baffle is located between the hot fluid inlet hole and the cold fluid inlet hole and is used to prevent the cold fluid and the hot fluid from entering the opposite holes.

[0013] Preferably, a spring frame is fixed above the valve body through a column. The spring frame is a ring-shaped structure with a circumferentially open inner side and an annular cavity; the upper part of the valve stem is connected to a pressure rod through a connecting shaft. The pressure rod and the connecting shaft form a rotating pair, enabling the pressure rod to rotate only in the vertical direction; an opening groove is provided on the spring frame, and the end of the pressure rod can enter the annular cavity through the opening groove and slide along the inner opening of the annular cavity; a spring is arranged in the annular cavity; one end of the spring is fixed in the annular cavity through a retaining piece, and the other end is in contact with the end of the pressure rod, and the elastic force can be changed under the action of the pressure rod to balance the torque transmitted by the driving coil spring, ensuring stable flow rate.

[0014] Furthermore, the original length of the spring is equal to half of the circumference of the annular cavity; the width of the circumferentially open inner side of the spring frame is slightly larger than the height of the cross-section of the end of the pressure rod, so that the end of the pressure rod can slide along the inner opening of the annular cavity.

[0015] Furthermore, continuous angular values are marked on the circumference of the spring frame, and the indication is determined by the position of the pressure rod to read the rotation angle of the spherical valve core.

[0016] In a second aspect, the present invention provides a temperature control method using the temperature control valve driven by shape memory alloy according to any one of the first aspect, specifically as follows:

[0017] In the initial state, the hot fluid inlet hole is aligned with the hot fluid inlet, and the cold fluid inlet hole is closed by the inner wall of the valve body. Only the hot fluid enters the spherical valve core; at this time, the temperature of the mixed fluid flowing out of the mixed fluid outlet hole is higher than that of the driving coil spring. When the driving coil spring contacts the mixed fluid, the driving coil spring expands, transmits torque and drives the valve stem to rotate, causing the spherical valve core to rotate towards the cold fluid inlet direction; during the rotation process, the connection degree between the hot fluid inlet hole and the hot fluid inlet decreases, the hot fluid flow rate decreases, the connection degree between the cold fluid inlet hole and the cold fluid inlet increases, the cold fluid flow rate increases, and the temperature of the mixed fluid flowing out of the mixed fluid outlet hole decreases; when the temperature of the mixed fluid is lower than the phase change temperature of the driving coil spring, the driving coil spring contracts, transmits torque in the opposite direction and drives the valve stem to rotate, causing the spherical valve core to rotate towards the hot fluid inlet direction; during the rotation process, the connection degree between the cold fluid inlet hole and the cold fluid inlet decreases, the cold fluid flow rate decreases, the connection degree between the hot fluid inlet hole and the hot fluid inlet increases, the hot fluid flow rate increases, and the temperature of the mixed fluid flowing out of the mixed fluid outlet hole increases to achieve response adjustment;

[0018] When the temperatures of the cold fluid and the hot fluid entering the spherical valve core change, the above response process will be repeated and finally reach a stable state, realizing the constant temperature control of the fluid flowing out of the mixed fluid outlet.

[0019] The present invention has the following beneficial effects compared with the prior art:

[0020] In the present invention, a driving coil spring made of shape memory alloy directly outputs torque to drive the valve stem to rotate, so as to change the valve flow area and regulate the flow of hot and cold fluids. This temperature control valve has a fast response speed, a long service life, a large driving stroke, a stable flow output, a simple structure and is easy to repair. At the same time, it overcomes the defects of the single driving form and limited application scenarios of the self-acting temperature control valve in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a half-sectional view of the temperature control valve involved in the present invention;

[0022] Figure 2 is a half-sectional view of the temperature control valve involved in the present invention;

[0023] Figure 3 is a partial sectional view of the temperature control valve involved in the present invention;

[0024] Figure 4 is a schematic diagram of the spherical valve core of the temperature control valve involved in the present invention;

[0025] Figure 5 is a schematic diagram of the connection structure between the connecting shaft and the pressure rod from different perspectives;

[0026] In the figures: 1, valve body; 2, baffle; 3, spherical valve core; 3-1, hot fluid inlet hole; 3-2, cold fluid inlet hole; 3-3, mixed fluid outlet hole; 4, valve stem; 5, driving coil spring; 6, column; 7, spring holder; 7-1, opening groove; 7-2, retaining piece; 8, connecting shaft; 9, pressure rod; 10, spring; 11, hot fluid inlet; 12, cold fluid inlet; 13, mixed fluid outlet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The present invention will be further described and explained below in conjunction with the drawings and specific embodiments. The technical features of each embodiment in the present invention can be combined correspondingly without conflict.

[0028] Such as Figure 1 and 2As shown in the figure, a temperature control valve driven by a shape memory alloy provided by the present invention mainly includes a valve body 1, a spherical valve core 3, a valve stem 4, and a spring holder 7. A hot fluid inlet 11 and a cold fluid inlet 12 are provided on the side wall of the valve body 1. Generally, the hot fluid inlet 11 and the cold fluid inlet 12 are arranged opposite to each other and are respectively located on the left and right sides of the valve body 1. A mixed fluid outlet 13 is provided at the bottom of the valve body 1. The hot fluid entering the valve body through the hot fluid inlet 11 and the cold fluid entering the valve body through the cold fluid inlet 12 can be mixed and flow out as a mixed fluid from the mixed fluid outlet 13. A valve stem 4 is provided inside the valve body 1. The upper part of the valve stem 4 passes through the valve body 1 and is located outside the valve body 1. The valve stem 4 can rotate in the valve body 1, and the connection between the valve body 1 and the valve stem 4 should be kept sealed to prevent the fluid entering the valve body 1 from escaping through the gap.

[0029] A driving coil spring 5 is sleeved and fixed on the lower part of the valve stem 4 located in the inner cavity of the valve body 1. The driving coil spring 5 can expand or contract through the temperature change of the mixed fluid it contacts, and output torque to drive the valve stem 4 to rotate, so as to change the flow area of the valve. The driving coil spring 5 is made of a shape memory alloy with a two-way memory effect. In the fully expanded state, it does not contact the inner wall of the valve body 1, that is, the cross-sectional diameter of the driving coil spring in the fully expanded state is slightly smaller than the inner diameter of the valve body 1 at the place where it is located, so as to prevent friction with the inner wall of the valve body 1 and thus affect the driving effect.

[0030] The material of the driving coil spring 5 can be selected according to the actual situation. For example, a nickel-titanium alloy with a two-way memory effect can be used. When the temperature of the mixed fluid is higher than the phase change temperature of the driving coil spring 5, the driving coil spring 5 expands and transmits a clockwise (or counterclockwise) torque, driving the valve stem 4 to rotate clockwise (or counterclockwise). At this time, the hot fluid flow rate decreases, the cold fluid flow rate increases, and the temperature of the mixed fluid decreases; when the temperature of the mixed fluid is lower than its phase change temperature, the driving coil spring 5 contracts and transmits a torque in the opposite direction, driving the valve stem 4 to rotate counterclockwise. At this time, the cold fluid flow rate decreases, the hot fluid flow rate increases, and the temperature of the mixed fluid increases. The driving coil spring 5 should be at a certain distance from the mixed fluid inlet hole 3-3, mainly to allow the hot and cold fluids to be fully mixed before contacting the driving coil spring 3-3, so as to ensure a better response adjustment effect.

[0031] The valve stem 4 located above the driving coil spring 5 is connected to the spherical valve core 3, and the spherical valve core 3 is located inside the valve body 1. As Figure 4As shown in the figure, the spherical valve core 3 is provided with 3 circular openings, namely the hot fluid inlet hole 3-1, the cold fluid inlet hole 3-2, and the mixed fluid outlet hole 3-3. The hot fluid inlet hole 3-1 and the cold fluid inlet hole 3-2 are opened on the side wall of the spherical valve core 3, and the mixed fluid outlet hole 3-3 is opened at the bottom. The mixed fluid outlet hole 3-3 is communicated with the mixed fluid outlet 13. By driving the spherical valve core 3 to rotate through the valve stem 4, the communication degrees between the hot fluid inlet hole 3-1 and the hot fluid inlet 11, and between the cold fluid inlet hole 3-2 and the cold fluid inlet 12 can be adjusted respectively to control the temperature of the mixed fluid flowing out from the mixed fluid outlet 13. That is to say, the spherical valve core 3 can rotate under the drive of the valve stem 4 to change the flow rates of the hot and cold fluids, thereby achieving the purpose of controlling the temperature of the mixed fluid.

[0032] In actual application, since the hot fluid inlet 11 and the cold fluid inlet 12 are generally located on opposite sides of the valve body 1 respectively, in order to achieve a better adjustment effect, the included angle between the connecting lines of the centers of the hot fluid inlet hole 3-1 and the cold fluid inlet hole 3-2 and the center of the spherical valve core 3 can be designed to be 90°. The inner diameters of the hot fluid inlet hole 3-1 and the hot fluid inlet 11 are equal, and the inner diameters of the cold fluid inlet hole 3-2 and the cold fluid inlet 12 are equal; the inner diameter of the mixed fluid outlet hole 3-3 is equal to that of the mixed fluid outlet 13, and it is arranged directly opposite to the mixed fluid outlet 13. At this time, the spherical valve core 3 can rotate between the first limit position and the second limit position to adjust the flow rates of the hot and cold fluids: in the first limit position, the hot fluid inlet hole 3-1 is directly opposite to the hot fluid inlet 11, and the cold fluid inlet hole 3-2 is blocked by the inner wall of the valve body 1, and only the hot fluid enters the spherical valve core 3; in the second limit position, the cold fluid inlet hole 3-2 is directly opposite to the cold fluid inlet 12, and the hot fluid inlet hole 3-1 is blocked by the inner wall of the valve body 1, and only the cold fluid enters the spherical valve core 3.

[0033] That is to say, when the spherical valve core 3 gradually rotates from the first limit position to the second limit position, the communication degree between the hot fluid inlet hole 3-1 and the hot fluid inlet 11 gradually decreases, and the communication degree between the cold fluid inlet hole 3-2 and the cold fluid inlet 12 gradually increases, so that the amount of cold fluid entering the spherical valve core 3 gradually increases and the amount of hot fluid gradually decreases, and the temperature of the mixed fluid shows a downward trend. On the contrary, when the spherical valve core 3 gradually rotates from the second limit position to the first limit position, the communication degree between the cold fluid inlet hole 3-2 and the cold fluid inlet 12 gradually decreases, and the communication degree between the hot fluid inlet hole 3-1 and the hot fluid inlet 11 gradually increases, so that the amount of hot fluid entering the spherical valve core 3 gradually increases and the amount of cold fluid gradually decreases, and the temperature of the mixed fluid shows an upward trend.

[0034] In order to prevent the cold and hot fluids from entering the opposite fluid inlets through the inlet holes, a baffle 2 can be vertically arranged on the valve stem 4 located in the inner cavity of the spherical valve core 3. The baffle 2 is located between the hot fluid inlet hole 3-1 and the cold fluid inlet hole 3-2, and can be set as a circular baffle structure, with a cross-sectional diameter slightly smaller than the diameter of the openings (cold fluid inlet hole 3-2 and cold fluid inlet 12) on the spherical valve core 3. In actual application, the baffle 2 can rotate with the valve stem 4, but its specific direction remains unchanged, and is used to prevent the cold fluid and the hot fluid from entering the opposite holes.

[0035] like Figure 3 As shown, in order to further ensure the flow stability, the following structure can be set above the valve body 1:

[0036] A spring frame 7 is fixed above the valve body 1 through a column 6. The spring frame 7 is an annular shell with an inner circumferential opening and an annular cavity. Figure 5 As shown, the upper part of the valve stem 4 is connected to a pressure rod 9 through a connecting shaft 8, and the pressure rod 9 and the connecting shaft 8 form a rotating pair, so that the pressure rod 9 can only rotate in the vertical direction and is limited in the horizontal direction. An opening groove 7-1 is provided on the spring frame 7, and the end of the pressure rod 9 can enter the annular cavity through the opening groove 7-1 and slide along the inner opening of the annular cavity. A spring 10 is provided in the annular cavity. One end of the spring 10 is fixed in the annular cavity through a baffle 7-2, and the other end is in contact with the end of the pressure rod 9. The elastic force can be changed under the action of the pressure rod 9 to balance the torque transmitted by the drive coil spring 5 and ensure the stability of the flow.

[0037] In actual application, the cross-section of the connecting shaft 8 can be I-shaped, and the pressure rod 9 is connected to the middle part of the connecting shaft 8. The connecting shaft 8 can limit the horizontal movement of the pressure rod 9, ensuring that the pressure rod 9 can only rotate around the connecting shaft 8 at a certain angle and squeeze the spring 10 under the drive of the valve stem 4.

[0038] In practical application, the spring 10 can be installed on the semicircular part on the left side of the spring frame 7, and its original length is equal to half of the circumference of the annular cavity of the spring frame 7. The baffle 7-2 can be a circular baffle, which acts in conjunction with the pressure rod 9 to limit the spring 10 to always be located on the semicircular part on the left side of the spring frame 7. The opening position of the opening groove 7-1 should be slightly away from the side where the spring 10 is located, so as to prevent the pressure rod 9 from sliding out of the opening groove 7-1 under the action of the spring 10. For example, the opening groove 7-1 can be set on the semicircular part on the right side of the spring frame 7, and the pressure rod 9 can enter the spring frame 7 through the opening groove 7-1 and then squeeze the spring 10 to balance the torque transmitted by the drive coil spring 5 to ensure stable flow. The width of the circumferential opening on the inner side of the spring frame 7 should be slightly larger than the height of the cross section at the end of the pressure rod 9, so that the end of the pressure rod 9 can slide along the opening on the inner side of the annular cavity.

[0039] On one side of the spring support 7 where the spring 10 is installed, angle values can be marked. The magnitude of the angle represents the rotation angle of the spherical valve core 3. The reading can be determined according to the position of the pressure rod 9. For example, the 0° position means that the hot fluid inlet hole 3-1 is facing the hot fluid inlet 11, and the cold fluid inlet hole 3-2 is blocked by the valve body 1, and no cold fluid flows in; the 90° position means that the cold fluid inlet hole 3-2 is facing the cold fluid inlet 12, and the hot fluid inlet hole 3-1 is blocked by the valve body 1, and no hot fluid flows in. Furthermore, the flow areas of the hot and cold fluid inlet holes can be calculated based on the angle values.

[0040] In addition, when the temperature control valve is working, the baffle 2 will generate different impact forces on both sides of the baffle due to different flow rates of the hot and cold fluids, and then output a certain torque. When the output torque is balanced with the torque output by the driving coil spring 5 and the elastic force of the spring 10, a stable state is reached. When the temperatures of the inlet hot and cold fluids change, the above response process will be repeated and finally a stable state will be reached to achieve the constant temperature control of the outlet fluid.

[0041] The temperature control method using the above temperature control valve driven by shape memory alloy is as follows:

[0042] In the initial state, the hot fluid inlet hole 3-1 is facing the hot fluid inlet 11, and the cold fluid inlet hole 3-2 is blocked by the inner wall of the valve body 1. At this time, only the hot fluid can enter the spherical valve core 3 through the hot fluid inlet hole 3-1. If the temperature of the mixed fluid flowing out of the mixed fluid outlet hole 3-3 is higher than that of the driving coil spring 5, when the driving coil spring 5 contacts the mixed fluid, the driving coil spring 5 will expand and transmit torque in the clockwise direction (as shown in the Figure 1 structure shown) to drive the valve stem 4 to rotate, and at the same time drive the spherical valve core 3 to rotate towards the cold fluid inlet 12. During the rotation process, the connection degree between the hot fluid inlet hole 3-1 and the hot fluid inlet 11 decreases, the hot fluid flow rate decreases, the connection degree between the cold fluid inlet hole 3-2 and the cold fluid inlet 12 increases, the cold fluid flow rate increases, and the temperature of the mixed fluid flowing out of the mixed fluid outlet hole 3-3 decreases. If the temperature of the mixed fluid is lower than the phase change temperature of the driving coil spring 5, the driving coil spring 5 will contract, transmit torque in the counterclockwise direction to drive the valve stem 4 to rotate, and at the same time, make the spherical valve core 3 rotate towards the hot fluid inlet 11. During the rotation process, the connection degree between the cold fluid inlet hole 3-2 and the cold fluid inlet 12 decreases, the cold fluid flow rate decreases, the connection degree between the hot fluid inlet hole 3-1 and the hot fluid inlet 11 increases, the hot fluid flow rate increases, and the temperature of the mixed fluid flowing out of the mixed fluid outlet hole 3-3 increases to achieve response adjustment.

[0043] When the temperatures of the cold fluid and the hot fluid entering the spherical valve core 3 change, the above response process will be repeated and finally a stable state will be reached to achieve the constant temperature control of the fluid flowing out of the mixed fluid outlet 13.

[0044] The design of the present invention is reasonable, and it has the characteristics of simple structure, continuous drainage, fast heat response speed, stable flow rate, long service life, and easy installation and maintenance.

[0045] The above-described embodiments are only a preferred solution of the present invention, but they are not intended to limit the present invention. Those of ordinary skill in the relevant technical field can still make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A temperature control valve driven by a shape memory alloy, characterized in that, it includes a valve body (1), a spherical valve core (3), a valve stem (4) and a spring holder (7); a hot fluid inlet (11) and a cold fluid inlet (12) are provided on the side wall of the valve body (1), a mixed fluid outlet (13) is provided at the bottom, and a rotatable valve stem (4) is provided inside; the upper part of the valve stem (4) passes through the valve body (1), and a driving coil spring (5) capable of driving the valve stem (4) to rotate through temperature change is sleeved on the lower part; the driving coil spring (5) is made of a shape memory alloy with a two-way memory effect and does not contact the inner wall of the valve body (1) in the fully relaxed state; the valve stem (4) above the driving coil spring (5) is connected to the spherical valve core (3), and the spherical valve core (3) is located inside the valve body (1); a hot fluid inlet hole (3-1) and a cold fluid inlet hole (3-2) are provided on the side wall of the spherical valve core (3), and a mixed fluid outlet hole (3-3) communicating with the mixed fluid outlet (13) is provided at the bottom; by driving the spherical valve core (3) to rotate through the valve stem (4), the communication degrees between the hot fluid inlet hole (3-1) and the hot fluid inlet (11), and between the cold fluid inlet hole (3-2) and the cold fluid inlet (12) can be respectively adjusted to control the temperature of the mixed fluid flowing out from the mixed fluid outlet (13); a spring holder (7) is fixed above the valve body (1) through a column (6), and the spring holder (7) is a ring-shaped structure with a circumferentially open inner side and an annular cavity; the upper part of the valve stem (4) is connected with a pressure rod (9) through a connecting shaft (8), and the pressure rod (9) and the connecting shaft (8) form a rotating pair, so that the pressure rod (9) can only rotate in the vertical direction; an opening groove (7-1) is provided on the spring holder (7), and the end of the pressure rod (9) can enter the annular cavity through the opening groove (7-1) and slide along the inner side opening of the annular cavity; a spring (10) is provided in the annular cavity; one end of the spring (10) is fixed in the annular cavity through a retaining piece (7-2), and the other end contacts the end of the pressure rod (9), and can change the elastic force under the action of the pressure rod (9) to balance the torque transmitted by the driving coil spring (5) to ensure stable flow.

2. The temperature control valve driven by a shape memory alloy according to claim 1, characterized in that, the cross-sectional diameter of the driving coil spring (5) in the fully relaxed state is slightly smaller than the inner diameter of the valve body (1) at the location.

3. The temperature control valve driven by a shape memory alloy according to claim 1, characterized in that, the connection part between the valve stem (4) and the top of the valve body (1) has airtightness.

4. The temperature control valve driven by a shape memory alloy according to claim 1, characterized in that, The included angle between the connecting lines of the centers of the hot fluid inlet hole (3-1) and the cold fluid inlet hole (3-2) and the center of the spherical valve core (3) is 90°. The hot fluid inlet (11) and the cold fluid inlet (12) are respectively located on opposite sides of the valve body (1). The inner diameters of the hot fluid inlet hole (3-1) and the hot fluid inlet (11) are equal, and the inner diameters of the cold fluid inlet hole (3-2) and the cold fluid inlet (12) are equal. The spherical valve core (3) can rotate between a first extreme position and a second extreme position to adjust the flow rates of the hot fluid and the cold fluid: in the first extreme position, the hot fluid inlet hole (3-1) faces the hot fluid inlet (11), and the cold fluid inlet hole (3-2) is closed by the inner wall of the valve body (1), and only the hot fluid enters the spherical valve core (3); in the second extreme position, the cold fluid inlet hole (3-2) faces the cold fluid inlet (12), and the hot fluid inlet hole (3-1) is closed by the inner wall of the valve body (1), and only the cold fluid enters the spherical valve core (3).

5. A shape memory alloy-driven temperature control valve according to claim 1, characterized in that, the inner diameter of the mixed fluid outlet hole (3-3) is equal to that of the mixed fluid outlet (13), and it is arranged facing the mixed fluid outlet (13).

6. A shape memory alloy-driven temperature control valve according to claim 1, characterized in that, a vertically arranged baffle (2) is connected to the valve stem (4) located in the inner cavity of the spherical valve core (3); the baffle (2) is located between the hot fluid inlet hole (3-1) and the cold fluid inlet hole (3-2) and is used to prevent the cold fluid and the hot fluid from entering the opposite holes.

7. A shape memory alloy-driven temperature control valve according to claim 1, characterized in that, the original length of the spring (10) is equal to half of the circumference of the annular cavity; the width of the circumferential opening on the inner side of the spring holder (7) is slightly larger than the height of the cross section of the end of the pressure rod (9), so that the end of the pressure rod (9) can slide along the opening on the inner side of the annular cavity.

8. A shape memory alloy-driven temperature control valve according to claim 1, characterized in that, the spring holder (7) is marked with continuous angular values in the circumferential direction, and the reading is determined by the position of the pressure rod (9) to read the rotation angle of the spherical valve core (3).

9. A temperature control method using the shape memory alloy-driven temperature control valve according to any one of claims 1 to 8, characterized in that, specifically as follows: In the initial state, the hot fluid inlet hole (3-1) is aligned with the hot fluid inlet (11), and the cold fluid inlet hole (3-2) is blocked by the inner wall of the valve body (1). Only the hot fluid enters the spherical valve core (3). At this time, the temperature of the mixed fluid flowing out of the mixed fluid outlet hole (3-3) is higher than that of the driving coil spring (5). When the driving coil spring (5) contacts the mixed fluid, the driving coil spring (5) expands, transmits torque and drives the valve stem (4) to rotate, causing the spherical valve core (3) to rotate towards the cold fluid inlet (12). During the rotation process, the degree of connection between the hot fluid inlet hole (3-1) and the hot fluid inlet (11) decreases, the hot fluid flow rate decreases, the degree of connection between the cold fluid inlet hole (3-2) and the cold fluid inlet (12) increases, the cold fluid flow rate increases, and the temperature of the mixed fluid flowing out of the mixed fluid outlet hole (3-3) decreases. When the temperature of the mixed fluid is lower than the phase change temperature of the driving coil spring (5), the driving coil spring (5) contracts, transmits torque in the opposite direction and drives the valve stem (4) to rotate, causing the spherical valve core (3) to rotate towards the hot fluid inlet (11). During the rotation process, the degree of connection between the cold fluid inlet hole (3-2) and the cold fluid inlet (12) decreases, the cold fluid flow rate decreases, the degree of connection between the hot fluid inlet hole (3-1) and the hot fluid inlet (11) increases, the hot fluid flow rate increases, and the temperature of the mixed fluid flowing out of the mixed fluid outlet hole (3-3) increases to achieve response regulation. When the temperatures of the cold fluid and the hot fluid entering the spherical valve core (3) change, the above response process will be repeated and finally reach a stable state, realizing the constant temperature control of the fluid flowing out of the mixed fluid outlet (13).

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