JPS6353379A - Fluid mixing valve - Google Patents

Abstract

PURPOSE:To accomplish accurate temperature control by using a plurality of driving elements different in transformation temperature, the material of which is shape memory alloy. CONSTITUTION:A plurality of driving elements 24 which are formed by shape memory alloy and different in transformation temperature are interposed between one end portion of a valve element 23 inserted in a casing 22 and one end portion of the casing 22. And elastic body 33 is resiliently disposed on the opposite side to the driving elements, with the valve element 23 interposed therebetween. In this arrangement, accurate temperature control can be accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a fluid mixing valve, and more particularly, the mixing ratio of high temperature fluid and low temperature fluid is automatically adjusted by a drive element made of a shape memory alloy. The present invention relates to a fluid mixing valve that always supplies mixed fluid at a predetermined temperature.

BACKGROUND OF THE INVENTION Shape memory alloys are known as one of the new functional materials whose existence has been confirmed relatively recently and whose mass production has become possible in terms of cost. This shape memory alloy is made of, for example, an alloy of nickel and titanium, and after imparting a desired shape to the alloy, a shape memory treatment is performed to heat the alloy to a temperature higher than the austenite transformation end temperature (Af humidity temperature). It is a metallic material that has the unique property of remembering the shape given to it metallographically.For this reason, even if it is deformed within a predetermined stress range, it will be heated to a temperature slightly higher than the temperature at the time of deformation. It instantly recovers to its original shape.

In view of this unique property of remembering the original shape, various applications in various industrial fields have been proposed. For example, seal joints for hydraulic pipes in aircraft are made using a shape memory alloy that is slightly smaller than the pipe diameter at room temperature, and after expanding the diameter of this joint at temperatures below zero, it is fitted onto the pipes to be joined. A very tight pipe connection is made by inserting the tube and then leaving it at room temperature to recover its original shape. Furthermore, since the shape changes in response to temperature changes, there are applications such as use as a drive source for opening and closing a damper of a cold air outlet of a cooler or the like.

Furthermore, this is another effective field of use for shape memory alloys.

In addition to the ones described above, several mixing valves have already been proposed in which, for example, a driving element made of a shape memory alloy is used to keep the mixing ratio of hot water and cold water constant at all times.

For example, in the mixing valve 10 shown in FIG.
and a cold water inflow path 13 are defined, and this high temperature water inflow path 12
and the cold water inlet passage 13 are divided into upper and lower parts by a valve seat 14 provided inside the casing 11. A hollow cylindrical control valve 15 is inserted into the casing 11 so as to be slidable up and down with the valve seat 14 in between, and hot water and cold water are supplied through a through hole 16 formed in the control valve 15. is configured such that it can flow into the hollow portion 15a of the control valve 15. A spring seat 17 is provided in the hollow portion 15a of the control valve 15, and a coil spring 18 made of a shape memory alloy material that remembers its shape in a compressed state is disposed above the spring seat 17. Further, a tension spring 19 made of a normal elastic metal material is disposed below. Note that the coil spring 18
It is assumed that the tension springs 19 and 19 are each attached in a tensioned state by appropriate locking means.

In the mixing valve 10 configured in this manner, when the temperature of the high-temperature water increases, the coil spring 18 made of a shape memory alloy set in a tensioned state returns to a compressed state due to its shape recovery stress, and the control valve 15 moves upward against the elasticity of the tension spring 19. As a result, the opening area of the through hole 16a facing the cold water inflow path 13 is widened, increasing the amount of cold water flowing into the control valve 15, and the opening area of the through hole 16b facing the high temperature water inflow path 12 is narrowed. Control valve 1
The amount of high-temperature water flowing into the control valve 15 is reduced, so that the temperature of the mixed hot water supplied from the hot water delivery path 20 via the control valve 15 is kept approximately constant.

Furthermore, if the temperature of the supplied high-temperature water decreases, the rigidity of the coil spring 18 made of a shape memory alloy is lost, and the tensile stress of the tension spring 19 becomes dominant, causing the control valve 15 to move downward, increasing the amount of high-temperature water. At the same time, the amount of cold water decreases to keep the temperature of the mixed water approximately constant.

Points to be Solved by the Invention As shown in Figure 12, shape memory alloys are a phenomenon that occurs along with thermoelastic martensitic transformation, and are subject to displacement at a certain temperature, that is, in the temperature range from As to Af. A sudden increase in volume appears. There is a temperature difference of about 10°C from As where the reverse transformation of the shape memory alloy begins to Af where the reverse transformation is completed, and when used as a driving element of the known mixing valve described in connection with FIG. 10, the valve Operation was inconsistent and it was difficult to accurately adjust the temperature of the mixed water.

In general, shape memory alloys have the disadvantage that even a slight change in the proportion of their components results in significantly different transformation temperatures; for example,
When a shape memory alloy that transforms at .degree. C. is manufactured, as shown in FIG. 11, the transformation temperature inevitably varies within a predetermined range. In this case, only products within the range A were selected and used, resulting in an extremely poor manufacturing yield in terms of cost.

Moreover, in order to accurately adjust the mixing temperature of high temperature water and cold water, it was necessary to use a further selected drive element from the manufactured shape memory alloy drive elements.

Purpose of the Invention The present invention has been proposed in view of the above-mentioned shortcomings inherent in the prior art, and uses a plurality of drive elements made of a shape memory alloy and having different transformation temperatures. It is an object of the present invention to provide a fluid mixing valve that allows accurate temperature control.

Means for Solving the Problems In order to overcome the above-mentioned problems and suitably achieve the intended purpose, the present invention connects a high-temperature fluid inflow path and a low-temperature fluid inflow path to the casing, and the high-temperature fluid inflow path A fluid mixing valve configured to adjust the mixing ratio of the high temperature fluid flowing in from the channel and the low temperature fluid flowing in from the low temperature fluid inflow channel by sliding a valve body disposed in the casing in the axial direction, A plurality of driving elements made of a shape memory alloy and having different transformation temperatures are inserted between one end of the valve body inserted into the casing and one axial end of the casing, and the driving elements are inserted with the valve body in between. The feature is that an elastic body is elastically inserted on the opposite side.

Embodiments Next, preferred embodiments of the fluid mixing valve according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic perspective view showing a preferred embodiment of the fluid mixing valve according to the present invention. It is configured to be driven by a plurality of driving elements 24 made of a shape memory alloy that has been memorized in a predetermined shape to maintain a constant mixing ratio of hot water and cold water. That is, a hot water pipe 25 and a cold water pipe 26 are connected to the cylindrical casing 22, and a discharge pipe 27 is connected to the cylindrical casing 22 for supplying the mixed water mixed inside the casing 22 to the outside. A spool valve 23 is disposed inside the casing 22 so as to be slidable in the axial direction.
It is divided into two room spaces. For example, the spool valve 23 is composed of flanges 28 and 29 that are inscribed in the inner peripheral surface of the casing 22 and spaced apart at a required interval, and a pallbrond 30 that is interposed between the flanges 28 and 29. Mixing chamber 3 between 29 and the casing inner wall surface
1 is defined. Further, the opening 25a of the hot water pipe 25 and the opening 26a of the cold water pipe 26 are set at opening positions so as to face the mixing chamber 31, respectively.

As shown in FIGS. 2 and 3, a knob 36 is screwed onto one end of the casing 22 so that it can move forward and backward in the axial direction by rotation, and between this knob 36 and one end of the spool valve 23 ( On the right side of the spool valve 23 in the figure, a plurality (three in this embodiment) of drive elements 24 of a desired shape and made of a shape memory alloy are inserted. The plurality of driving elements 2
4 have different transformation temperatures, and are arranged at each vertex of a virtual triangle at one end of the spool valve 23, as shown in FIG. That is, this driving element 24 is a member made of a wire made of the shape memory alloy wound in a spiral shape, and is in an extended state with gaps between each turn;
The length in the axial direction can be in a state where the length in the axial direction fluctuates greatly, such as a compressed state in which the intervals between each turn are tight. In this embodiment, it is assumed that the coil-shaped drive element 24 memorizes a shape in an extended state in which each turn is spaced apart. Note that the knob 36 is removably screwed onto the casing 22, so if the set temperature is to be significantly changed due to changes in outside temperature or personal preference, the driving element 24 can be easily replaced by removing the knob 36. can do.

The mixing chamber 31 defined by both flanges 28 and 29 of the spool valve 23 and the discharge chamber 37 defined on the right side of the spool valve 23 to which the discharge pipe 27 is connected and in which the drive element 24 is inserted. are in fluid communication with each other via a communication pipe 38. Therefore, the mixed water mixed in the mixing chamber 31 is supplied to the discharge chamber 37 via the communication pipe 38,
It is supplied to the outside of the mixing valve 21 via a discharge pipe 27 that is connected to the discharge chamber 37 .

An adjustment knob 32 is screwed onto the other end of the casing 22, and a bias acting as an elastic body is provided between the adjustment knob 32 and one end of the spool valve 23 (to the left of the spool valve 23 in the figure). A spring 33 is inserted. The stress of the bias spring 33 is set in advance to be the same as the stress generated when two of the three drive elements 24 are transformed in the embodiment.

By moving the adjustment knob 32 forward and backward in the axial direction of the casing 22, the knob 32 and the spool valve 23
The amount of hot water and cold water flowing into the mixing chamber 31 can be adjusted by adjusting the distance between the mixing chamber 31 and the mixing chamber 31. That is, the flanges 28 and 29 of the spool valve 23 adjust the opening areas of the opening 25a of the hot water pipe 25 and the opening 26b of the cold water pipe 26 facing the mixing chamber 31 of the casing 22. An indicator 34 that protrudes outside the casing 22 and extends in the axial direction is fixed to the end of the spool valve 23 that the bias spring 33 comes into contact with, and cooperates with a scale plate 35 provided on the casing 22. The setting temperature of the mixed water obtained by the mixing valve 21 can be displayed.

5 to 7 show another embodiment of the present invention, the basic configuration is the same as the embodiment shown in FIGS. 1 to 4, but a hot water pipe 25 and a cold water pipe The opening area of the opening 25a of the hot water pipe 25 is adjusted by the flange 28 of the spool valve 23, and the opening area of the opening 26a of the cold water pipe 26 is adjusted by the flange 28 of the spool valve 23.
It is adjusted by. In this example.

The stress of the bias spring 33 is set to be smaller than the stress generated when one driving element 24 transforms, and the temperature can be adjusted in stages. That is, as shown in FIGS. 5 to 7, the spool valve 23 is slid to the left of the casing 22 each time the drive element 24 is transformed to adjust the mixing ratio of hot water and cold water. be.

FIGS. 8 and 9 show still another embodiment of the present invention, in which a part of the mixed water supplied to the discharge pipe 27 is guided to a regulating device 40 having a bimetal 48 as a driving element. The amount of hot water and cold water flowing into the casing 22 is adjusted immediately before the casing 22. Bimetal 48.

Since the displacement is caused by the difference in the thermal expansion coefficients of the two alloys, the amount of deformation due to temperature changes is small, but the accuracy can be improved because the response to temperature changes is accurate. A frame 44 of the adjustment device [40] is arranged and fixed to the casing 22, and the frame 44 and the discharge pipe 27 are communicated through a bypass pipe 41. Further, a pilot valve 42 having through holes 42a and 42b is slidably disposed between the casing 22 and the hot water pipe 25 and the cold water pipe 26, and the hot water pipe 25 and cold water pipe 26
and communicate with the casing 22.

One end of the pilot valve 42 (left side in the figure)
A rod 43 that is slidably inserted into the frame 44 is fixed to the frame body 44 . The frame body 44 is divided into two chambers 4 by a picture wall 45.
An abutment plate 46 is fixed to an end of a rod 43 defined by chambers 4a and 44b and extending into one chamber 44a. Also, a bias spring 47 is installed between this contact plate 46 and the drawing wall 45.
is elastically inserted to constantly urge the rod 43 to the left. The other chamber 4 defined by the picture wall 45
An inner diameter portion of a bimetal 48 formed in the shape of a disc spring on the rod 43 is inserted through the rod 4b.

The bypass pipe 41 is connected to the chamber 44b in which the bimetal 48 is arranged.

A large-diameter sleeve 49 is fitted onto the rod 43 on the right side of the bimetal 48 so that the inner peripheral edge of the bimetal 48 comes into contact with one end of the sleeve 49.

Further, the outer peripheral edge of the bimetal 48 is disposed so as to come into contact with the partition wall 45, and the bimetal 48 is configured to be held between the partition wall 45 and the sleeve 49. Note that the disc spring-shaped bimetal 48 is set so that its outer circumferential radius becomes smaller as the temperature changes. Therefore, due to the temperature of the mixed water supplied through the bypass pipe 41, the bimetal 48 is deformed, and the rod 43 is moved left and right against the elastic force of the bias spring 47. The holes 42a and 42b reduce the area of the opening 25a of the hot water pipe 25 and the opening 2 of the cold water pipe 26.
6a is adjusted to keep the temperature of the mixed water constant.

(Operation of Example) Next, the operation of the fluid mixing valve configured as described above will be explained. As mentioned above, it is assumed that each of the three drive elements 24 remembers its shape in the expanded state. Further, the transformation temperatures of the three driving elements 24 are different from each other, and for example, the transformation temperature of each of the driving elements 24 is set to a = (t
−α)”C, b = t′c.

The case will be explained assuming that c=(t+α)°C. It is assumed that mixed water at t° C. is supplied by this valve 21. As shown in FIG. 2, the spool valve 23 is slid in the axial direction of the casing 22 so that the temperature of the mixed water of hot water and cold water is t°C, based on the numerical value determined in advance through experiments etc. The opening areas of the opening 25a of the pipe 25 and the opening 26a of the cold water pipe 26 are adjusted. That is, the spool valve 23 is moved to a position where the stress of the bias spring 33 and the stress of the two driving elements 24 are balanced.

If hot water and cold water are supplied to this mixing valve 21,
Hot water and cold water are mixed in a mixing chamber 31 defined by the flanges 28, 29 of the spool valve 23, and this mixed water is transferred via a communication pipe 38 to the discharge chamber 31 in which the drive element 24 is arranged.
7 and is supplied to the outside from the discharge chamber 37 via the discharge pipe 27.

In this case, the drive elements 24, 24 of a and b are transformed into an elongated state by the mixed water, and maintain a balance with the stress of the bias spring 33.

When the amount of hot water increases in the above-mentioned state and the temperature of the mixed water rises to t°C or higher, for example to (t+α)°C, the drive element 2
The remaining one C of 4 transforms into an extended state. Since the stress of the bias spring 33 is balanced with the stress of the two driving elements 24, when the driving element 24 of C is in an extended state, the spool valve 23 is moved to the left as shown in FIG. be moved to. and the flange 29 of the spool valve 23
narrows the opening 25a of the hot water pipe 25, and the opening 26a of the cold water pipe 26, which had been narrowed by the flange 28 of the spool valve 23, widens, increasing the amount of cold water flowing in and lowering the temperature of the mixed water. Keep it constant.

Next, when the temperature of the mixed water becomes lower, for example lower than the transformation temperature of the drive elements 24 of b and c, the two drive elements 24 lose their rigidity and become compressible. , are compressed by the stress of the bias spring 33. Therefore, the spool valve 23 moves to the right, opening 2 of the cold water pipe 26.
6a is narrowed and the area of the opening 25a of the hot water pipe 25 is widened to raise the temperature of the mixed water and keep it constant.

In this way, the bias spring 33 and the two drive elements 2 are always connected.
4, the balance is maintained, so that if a temperature change occurs, the temperature can be adjusted by the third driving element 24. That is, the temperature of the mixed water is adjusted by the stress of the bias spring 33 and the stress of the plurality of driving elements 24, and a constant amount of mixed water is always supplied to the outside.

In another embodiment of the invention, the stress in the bias spring 33 is
One driving element 24 is set to be smaller than the stress that occurs during transformation, and the bias spring 33 is adjusted to the optimum position of the spool valve 23 so that the temperature of the mixed water is lower than the set temperature. It shall be adjusted using the knob 34. Therefore, when hot water and cold water are supplied to this mixing valve 21, as shown in FIG. let Then, the opening area of the opening 26a of the cold water pipe 26 is sandwiched between the flange 29 of the spool valve 23, and the opening area of the opening 25a of the hot water pipe 25 is widened to increase the temperature of the mixed water. When the temperature of the mixed water increases, the second drive element 24 recovers its memory of being in the extended state and moves the spool valve 23 further to the left to reduce the amount of cold water and reduce the amount of hot water. Increase the temperature of the mixed water.

As shown in FIG. 7, the temperature of the mixed water can be kept constant by setting the temperature so that the mixed water reaches the desired set temperature when all three drive elements 24 are restored to their extended states. Can be done.

In still another embodiment shown in FIGS. 8 and 9, -
Bimetal 48 temperature control device for fine temperature control. ! 40, and the deformation of this bimetal 48 achieves accurate temperature control. When hot water and cold water flow into the casing 22, the mixed water mixed in the mixing chamber 31 flows through the communication pipe 38 into the discharge chamber 3.
7, and mixed water is supplied from this discharge chamber 37 to the outside of the valve 21 via the discharge pipe 27. In this case, the mixed water is introduced to the adjusting device 4o via the bypass pipe 41 connected to the discharge pipe 27, and the disc spring-shaped bimetal 48 is immersed in the mixed water. When the temperature of the mixed water introduced into the adjusting device 40 increases, the bimetal 48 deforms so that the outer radius of the bimetal 48 becomes smaller, as shown in FIG. and bimetal 4
The rod 43 with which the inner circumferential edge of the pilot valve 8 is in contact is pressed rightward to press and bias the pilot valve 42 rightward.

At this time, the opening 25a of the hot water pipe 25 is pinched, the amount of hot water flowing from the hot water pipe 25 into the casing 22 decreases, and the temperature of the mixed water flowing into the mixing chamber 31 decreases. is kept constant.

Furthermore, when the temperature of the mixed water becomes low, the rigidity of the bimetal 48 is lost as shown in FIG. , the temperature of the mixed water flowing into the mixing chamber 31 is kept constant.

Although this embodiment describes a valve for mixing liquids, the present invention is not limited to this embodiment, and can be applied to other fluids, such as an air conditioner that mixes hot air and cold air to supply moderately hot air. It can also be used as a mixing valve for equipment.

Effects of the Invention According to the fluid mixing valve configured as described above, the temperature of the mixed fluid mixed within the casing can be controlled even if there are variations in the transformation temperatures of the driving elements constituting the individual shape memory alloys.
Accurate temperature control as a whole becomes possible, and the ratio of selection from a large number of shape memory alloy elements can be reduced, so yields can be reduced and manufacturing costs can be reduced.

[Brief explanation of the drawing]

The drawings show a preferred embodiment of the fluid mixing valve according to the present invention, and FIG. 1 is a schematic perspective view showing the fluid mixing valve according to the embodiment of the present invention, and FIGS. A vertical cross-sectional explanatory diagram showing a schematic configuration of a fluid mixing valve according to an embodiment of the invention, FIG. 4 is a cross-sectional view of the fluid mixing valve shown in FIG. 1, and FIGS. FIGS. 8 and 9 are longitudinal cross-sectional explanatory views showing the operation over time of a fluid mixing valve according to another embodiment of the present invention, and FIG. A vertical cross-sectional explanatory diagram showing a schematic configuration of a mixing valve according to the prior art, Fig. 11 is a control chart during the manufacture of a shape memory alloy, and Fig. 12 shows the amount of displacement (deflection) of the shape memory alloy due to temperature changes. This is a diagram. 21... Fluid mixing valve 22... Casing 2
3... Spool valve 24... Drive element 25.
...Hot water pipe 26...Cold water pipe 33...Bias spring J5 FIG, 3 FIo, 4 FIo, 5 FIG, 7 FIG, 10 FIo, 11 FIG, 12 51 戊 /”c;

Claims (3)

[Claims] (1) A high-temperature fluid inflow path and a low-temperature fluid inflow path are connected to the casing, and the mixing ratio of the high-temperature fluid flowing in from the high-temperature fluid inflow path and the low-temperature fluid flowing in from the low-temperature fluid inflow path is determined within the casing. In the fluid mixing valve configured to be adjusted by sliding a valve body provided in the casing in the axial direction, a shape memory alloy is disposed between one end of the valve body inserted into the casing and one axial end of the casing. A fluid mixing valve characterized in that a plurality of driving elements having different transformation temperatures are inserted, and an elastic body is elastically inserted on the opposite side of the driving element with the valve body in between. (2) A patent claim characterized in that the stress of the elastic body is larger than the stress generated in one driving element when the driving element transforms, and smaller than the total stress of the plurality of driving elements. The fluid mixing valve according to item 1. (3) The fluid mixing valve according to claim 1, wherein the stress of the elastic body is smaller than the stress generated when one of the drive elements transforms.