safety valve

Abstract

To provide a safety valve which does not prevent discharge of a fluid when a valve is opened.SOLUTION: A safety valve 1 includes a body 2 including an introduction passage 24 of a fluid and a valve seat 25 formed around an inner end part of the introduction passage 24, a fixing member 4 provided with an opening communicating with the outside to be fixed to the body 2, a valve body 3 that can come to or separate from the valve seat 25, a lock part arranged between the valve body 3 and the fixing member 4, and a coil spring 5 for energizing the valve body 3 to a valve seat side with respect to the fixing member 4. When pressure in the introduction passage exceeds valve opening pressure, the fluid in the introduction passage can be made to flow into a clearance flow passage between the valve body 3 and the body 2 by separating the valve body 3 from the valve seat 25 against energization force of the coil spring 5, and the lock part can form an intermediate flow passage for making the clearance flow passage communicate with the opening between the valve body 3 and the fixing member 4 by being sandwiched by the displaced valve body 3 and the fixing member 4 to hold a space between the valve body 3 and the fixing member 4 in an axial direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a safety valve.

Background Art

[0002] For example, there is known a safety valve that opens when the refrigerant in a refrigeration cycle reaches a high pressure equal to or higher than a predetermined value, and protects the refrigeration cycle equipment from abnormal high pressure by discharging the high-pressure refrigerant.

[0003] Patent Document 1 discloses a safety valve that closes a pressure inlet by urging a valve body toward a valve seat by the biasing force of a compression coil spring. According to such a safety valve, when the internal pressure of the pressure inlet exceeds the opening pressure, the valve body separates from the valve seat and the pressure inlet is opened, so that the fluid that has entered the safety valve from the pressure inlet can be discharged to the outside through the through-hole of the plate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, in the safety valve of Patent Document 1, since the plate is caulked and fixed to the body, the biasing force of the compression coil spring is constant, and therefore the opening pressure is substantially constant. On the other hand, by forming a male thread on the outer periphery of the plate and screwing it into the female thread formed on the body, it becomes possible to adjust the opening pressure to a desired value. Specifically, by changing the amount of screwing of the plate with respect to the body, the biasing force of the compression coil spring is changed, and the opening pressure can be adjusted.

[0006] In such a safety valve, a high valve opening pressure can be achieved by bringing the plate closer to the valve body to increase the biasing force of the compression coil spring, without replacing the compression coil spring, and a low valve opening pressure can be achieved by moving the plate away from the valve body to decrease the biasing force of the compression coil spring.

[0007] However, if the plate is brought close to the valve body to achieve a high valve opening pressure, the valve body may be strongly pushed towards the plate and come into close contact with the plate, for example, when the internal pressure of the pressure inlet becomes excessive. In such cases, the valve body may block the opening of the plate, potentially hindering fluid release. A similar problem can occur even with safety valves that maintain a constant valve opening pressure, for example, when the distance between the plate and the valve body is shortened to reduce size.

[0008] The present invention has been made in view of the above problems, and aims to provide a safety valve that does not obstruct the release of fluid when the valve is opened. [Means for solving the problem]

[0009] The safety valve of the present invention is A body comprising a fluid introduction passage and a valve seat formed around the inner end of the introduction passage, A fixing member having an opening that communicates with the outside and fixed to the main body, A valve body that can move closer to or further away from the valve seat, A locking portion disposed between the valve body and the fixing member, The valve body is biased toward the valve seat side relative to the fixing member by a coil spring, When the pressure in the introduction passage exceeds the valve opening pressure, the valve body separates from the valve seat against the biasing force of the coil spring, allowing the fluid in the introduction passage to flow into the gap passage between the valve body and the main body. The locking portion is sandwiched between the displaced valve body and the fixing member, thereby maintaining the axial distance between the valve body and the fixing member, and making it possible to form an intermediate passage between the valve body and the fixing member that connects the gap passage and the opening. the law of nature, The locking portion is a part of a shaft disposed on the valve body at a position shifted radially from the center of the valve body. The shaft comprises a first shaft portion, a large-diameter shaft portion, and a second shaft portion having a smaller diameter than the large-diameter shaft portion, with the large-diameter shaft portion being the locking portion. It is characterized by the following: [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a safety valve that can suppress fluid leakage, ensure a stable valve opening pressure, and enable smooth operation. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is an axial cross-sectional view of a safety valve according to an embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view showing a magnified portion of the safety valve in Figure 1. [Figure 3] Figure 3 is a cross-sectional view AA of the safety valve in Figure 1. [Figure 4] Figure 4 is an axial cross-sectional view of the safety valve in the open position. [Figure 5] Figure 5 is a cross-sectional view showing a magnified portion of the safety valve in Figure 4. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings. While this description primarily focuses on the application of the present invention to safety valves used in refrigeration cycles such as those in car air conditioners, the safety valves according to the present invention can be applied to a variety of other applications besides refrigeration cycles.

[0013] Figure 1 is an axial cross-sectional view of the safety valve 1 in the closed state of this embodiment. Figure 2 is an enlarged cross-sectional view showing a part of the safety valve 1 in Figure 1. Figure 3 is a cross-sectional view AA of the safety valve 1 in Figure 1, where the configuration in the direction of arrow A is shown by a solid line, and the structure in the direction opposite to arrow A is shown by a dashed line. Figure 4 is an axial cross-sectional view of the safety valve 1 in the open state. Figure 5 is an enlarged cross-sectional view showing a part of the safety valve 1 in Figure 4. The center line of the safety valve 1 is defined as axis L.

[0014] In Fig. 1, the safety valve 1 is composed of a main body 2, a valve body 3, a screw member (fixing member) 4, and a coil spring 5. The main body 2 made of metal (for example, brass) is continuously formed from a peripheral wall 21 whose outer periphery is hexagonal cylindrical and inner periphery is cylindrical as shown in Fig. 3, an end wall 22 that shields one end of the peripheral wall 21, and a shaft portion 23 implanted at the center of the end wall 22. A male thread 23a is formed around the shaft portion 23.

[0015] An introduction passage 24 penetrating the shaft portion 23 and the end wall 22 is formed along the axis L. The introduction passage 24 opens into the main body 2. A tapered valve seat 25 is formed on the surface of the end wall 22 facing the valve body 3 around the inner end of the introduction passage 24.

[0016] The peripheral wall 21 of the main body 2 has a reduced-diameter inner peripheral portion 21a on the end wall 22 side and an enlarged-diameter inner peripheral portion 21b on the end portion side opposite to the end wall 22. The reduced-diameter inner peripheral portion 21a and the enlarged-diameter inner peripheral portion 21b may be connected by a tapered inner peripheral portion. A female thread 21c is formed in the enlarged-diameter inner peripheral portion 21b.

[0017] The valve body 3 is disposed slidably along the axis L within the reduced-diameter inner peripheral portion 21a. The valve body 3 made of metal (for example, brass) is continuously formed from a body portion 31 whose outer periphery is substantially square cylindrical as shown in Fig. 3 and a conical portion 32 that expands as it moves away from the introduction passage 24 side. The valve body 3 is not limited to being substantially square cylindrical and may be substantially triangular cylindrical or substantially polygonal cylindrical with five or more sides.

[0018] In Fig. 3, among the four planes 31a that constitute the outer periphery of the body portion 31, those adjacent to each other in the circumferential direction are connected by a partial cylindrical surface 31b coaxial with the axis L. This partial cylindrical surface 31b serves as a sliding surface slidable with respect to the reduced-diameter inner peripheral portion 21a.

[0019] In Fig. 1, the end of the conical portion 32 on the introduction passage 24 side is a flat surface that enters the introduction passage 24 in the assembled state, and a conical recess 32a is formed at the center thereof.

[0020] On the end face of the body portion 31 opposite to the introduction passage 24 side, four (only two are shown in Figure 1) blind holes 31c are formed at equal intervals in the circumferential direction. A shaft 33 of a common shape is planted in each of the blind holes 31c that constitute the mounting opening. It is preferable to have multiple shafts 33.

[0021] In Figure 2, the cylindrical shaft 33 consists of a short shaft portion (first shaft portion) 33a that is press-fitted into the blind hole 31c, a large-diameter shaft portion (locking portion) 33b which is preferably larger in diameter than the short shaft portion 33a, and a long shaft portion (second shaft portion) 33c which is smaller in diameter than the large-diameter shaft portion 33b, all coaxially connected and positioned radially shifted with respect to the center of the valve body 3. The diameters of the short shaft portion 33a and the long shaft portion 33c are preferably equal, but they may be different. When the short shaft portion 33a is press-fitted into the blind hole 31c, the end of the large-diameter shaft portion 33b abuts against the end face of the body portion 31. The long shaft portion 33c extends parallel to the axis L.

[0022] In Figures 1 and 2, the short cylindrical threaded member 4 has a cylindrical hole 41 on the side facing the valve body 3, and a hexagonal tubular engagement hole 42 on the outward-facing side, which is in communication with the cylindrical hole 41 and into which a tool (not shown) can be engaged. The cylindrical hole 41 and the engagement hole 42 form an opening that communicates with the outside. A male thread 43 is formed on the outer circumference of the threaded member 4.

[0023] Furthermore, the threaded member 4 has four through holes 44 (only two are shown in Figure 1) that penetrate radially outward from the cylindrical hole 41, passing through along the axis L and being formed at equal intervals in the circumferential direction. The long axis portion 33c of the shaft 33 is inserted into the through holes 44 so as to be movable relative to it in the axial direction. Preferably, the end of the long axis portion 33c is located inside the through holes 44 (not protruding). The inner diameter of the through holes 44 is smaller than the outer diameter of the large-diameter shaft portion 33b. In the closed valve state shown in Figures 1 and 2, the large-diameter shaft portion 33b and the threaded member 4 are spaced apart.

[0024] A coil spring 5 is positioned inside the cylindrical hole 41. The inner end of the coil spring 5 abuts against the end face of the body portion 31, and its outer end abuts against the stepped portion of the engagement hole 42 between the cylindrical hole 41 and the body. The coil spring 5 biases the conical portion 32 toward the introduction passage 24 relative to the main body 2 via the threaded member 4. In accordance with this biasing force, the outer circumferential surface of the conical portion 32 seats on the valve seat 25, thereby shielding the introduction passage 24.

[0025] When assembling the safety valve 1, first the short shaft portions 33a of each shaft 33 are pressed into the blind holes 31c of the valve body 3 to fix the shafts 33 to the valve body 3. Then, coil springs 5 ​​are placed inside the four shafts 33, and the threaded members 4 are brought closer to the valve body 3, and the long shaft portions 33c are inserted through the through holes 44. It is preferable that the dimensions are such that the long shaft portions 33c do not fall out of the through holes 44 when the coil springs 5 ​​are at their free length.

[0026] The valve body 3 and threaded member 4, assembled in this manner, are inserted into the peripheral wall 21 of the main body 2 from the valve body 3 side, and the male thread 43 of the threaded member 4 is screwed into the female thread 21c while compressing the coil spring 5. At this time, the valve body 3, which is connected to the threaded member 4 via the shaft 33, is screwed forward together with the threaded member 4, which is rotated via a tool (not shown), and the outer surface of the conical portion 32 is seated on the valve seat 25. After that, after adjusting the valve opening pressure, the threaded member 4 is fixed to the main body 2, resulting in the closed valve state shown in Figure 1. At this time, the conical portion 32 is pressed against the valve seat 25 by the initial biasing force of the coil spring 5. Preferably, the threaded member 4 is sealed and fixed to the main body 2 with a sealant or the like, and in that case, it is desirable that the sealant or the like does not obstruct the through hole 44. However, the threaded member 4 may also be fixed to the main body 2 by crimping.

[0027] (Safety valve operation) During the operation of the refrigeration cycle, the internal pressure of the introduction passage 24 increases as the refrigerant pressure rises. When this internal pressure exceeds the valve opening pressure, the sliding surface 31b (partial cylindrical surface) of the body portion 31 slides against the reduced diameter inner circumference portion 21a against the biasing force of the coil spring 5, causing the valve body 3 to be displaced to the right (in the valve opening direction) in Figure 1 relative to the main body 2. As a result, the conical portion 32 separates from the valve seat 25, and the refrigerant flows out through the gap between them. The flowing refrigerant passes through the gap passage CL (Figures 2 and 3) formed between the reduced diameter inner circumference portion 21a and the flat surface 31a of the body portion 31, and heads towards the screw member 4.

[0028] (Preventing the valve body from rotating via the shaft) In this embodiment, the valve body 3 and the threaded member 4 are connected via four shafts 33, and the threaded member 4 is further fixed to the main body 2. Therefore, even if, for example, the refrigerant flowing from the introduction passage 24 towards the valve body 3 creates a vortex that applies a rotational force to the valve body 3 around the axis L, the shafts 33 support the rotational force, thereby suppressing the rotation of the valve body 3. This suppresses wear between the outer surface of the conical portion 32 and the valve seat 25. Note that at least one shaft 33 is sufficient to prevent the rotation of the valve body 3.

[0029] However, in order for a single shaft 33 to prevent the rotation of the valve body 3, the shaft 33 must be located off-center from the center of the valve body 3.

[0030] (Intermediate channel formation by the large-diameter shaft) Here, if the pressure in the introduction passage 24 is excessive, the valve body 3 is pressed toward the threaded member 4 by that pressure, as shown in Figure 4. In this case, according to this embodiment, as shown in Figure 5, the shaft 33 is displaced toward the threaded member 4 along with the valve body 3, and the large-diameter shaft portion 33b comes into contact with the end face around the through hole 44 of the threaded member 4. That is, the large-diameter shaft portion 33b is sandwiched between the valve body 3 and the threaded member 4, preventing further displacement of the valve body 3. In this case, because the large-diameter shaft portion 33b ensures the gap between the valve body 3 and the threaded member 4, the refrigerant that has passed through the gap passage CL can smoothly pass through the intermediate passage IM (Figures 3, 5), which has a relatively large flow path cross-section formed between adjacent large-diameter shaft portions 33b (at least adjacent to the large-diameter shaft portions 33b), as shown by arrow B in Figure 5, and flow out to the outside through the cylindrical hole 41 and engagement hole 42 of the threaded member 4. In order to evenly support the pressing force of the valve body 3, it is preferable that multiple large-diameter shaft portions 33b are arranged at equal intervals in the circumferential direction.

[0031] (Detection of valve open state using the long shaft) As is clear from comparing the closed state (Figure 2) and the open state (Figure 5), the valve body 3 is displaced axially with respect to the screw member 4, so the amount of protrusion of the long axis portion 33c of the shaft 33 protruding from the through hole 44 is different in both states. For example, when the fluid is a gas, it may not be possible to directly see the fluid flowing out of the safety valve 1, and therefore confirmation that the safety valve 1 is in the open state may be delayed. In contrast, according to this embodiment, when the safety valve 1 is in the open state, the long axis portion 33c protrudes outwards from the through hole 44, so it can be seen with the naked eye by an inspector, for example. This makes it possible to immediately recognize that the safety valve 1 is in the open state and to quickly grasp pressure abnormalities in the refrigeration cycle.

[0032] When the refrigerant pressure in the introduction passage 24 decreases and the valve opening pressure falls below the threshold, the valve seat 25 and the conical portion 32 come into contact, and the outflow of refrigerant through the safety valve 1 is stopped.

[0033] It should be noted that the present invention is not limited to the embodiments described above. Within the scope of the present invention, any component of the embodiments described above can be modified. Furthermore, any component can be added or omitted in the embodiments described above. For example, in the embodiments described above, the locking portion is provided by attaching a shaft 33, which is a separate component from the valve body 3, to the valve body 3 side, but in other examples, the locking portion may be formed integrally with the valve body 3. Here, "the locking portion is formed integrally with the valve body" means that the locking portion and the valve body are formed from a single component. In other examples, the locking portion may be provided on a screw member (fixing member) 4. The locking portion may be formed integrally with the screw member, or it may be formed as a separate component from the screw member 4 and fixed to the screw member 4. As an example of this, the short shaft portion of the shaft may be cut and the long shaft portion may be press-fitted into the through hole of the screw member to attach the large-diameter shaft portion as the locking portion to the screw member side. Here, "the locking portion is formed integrally with the screw member" means that the locking portion and the screw member are formed from a single component.

[0034] Alternatively, a marker may be placed on the part of the shaft that protrudes from the outside, allowing the valve opening to be determined by visual inspection of this marker. For example, a scale (paint, stamping, etc.) can be marked on the shaft, allowing the valve opening to be determined by visual inspection of this scale. Another example is that the part of the shaft that protrudes from the outside is divided into multiple regions along its length, and each region is painted with a different color, allowing the valve opening to be determined by the color of the base of the part that protrudes from the shaft.

[0035] This specification includes disclosures of the following inventions. (First form) A body comprising a fluid introduction passage and a valve seat formed around the inner end of the introduction passage, A fixing member having an opening that communicates with the outside and fixed to the main body, A valve body that can move closer to or further away from the valve seat, A locking portion disposed between the valve body and the fixing member, The valve body is biased toward the valve seat side relative to the fixing member by a coil spring, When the pressure in the introduction passage exceeds the valve opening pressure, the valve body separates from the valve seat against the biasing force of the coil spring, allowing the fluid in the introduction passage to flow into the gap passage between the valve body and the main body. The locking portion is sandwiched between the displaced valve body and the fixing member, thereby maintaining the axial distance between the valve body and the fixing member, and making it possible to form an intermediate passage between the valve body and the fixing member that connects the gap passage and the opening. A safety valve characterized by the following features.

[0036] (Second form) The locking portion is a part of a shaft disposed on the valve body at a position shifted radially from the center of the valve body. A first embodiment of a safety valve characterized by the following:

[0037] (Third form) The shaft comprises a first shaft portion, a large-diameter shaft portion, and a second shaft portion having a smaller diameter than the large-diameter shaft portion, with the large-diameter shaft portion being the locking portion. A second form of safety valve characterized by the following:

[0038] (Fourth form) The first shaft portion is press-fitted into the mounting opening of the valve body. A third form of safety valve characterized by the following:

[0039] (Fifth form) The second shaft portion is inserted through the through hole of the fixing member so as to be displaceable relative to the safety valve in the axial direction, When the valve body is displaced toward the fixed member, the state in which the second shaft portion protrudes from the through hole can be visually observed from outside the safety valve. A third or fourth form of safety valve characterized by the above.

[0040] (Sixth form) Multiple shafts are attached to the valve body. A safety valve characterized by any of the third to fifth embodiments.

[0041] (Seventh form) The valve body has a substantially polygonal cylindrical shape with a plurality of planes along the circumferential direction, and the gap flow path is formed between the planes and the inner circumferential surface of the main body. A safety valve according to any of the first to sixth embodiments, characterized by the above.

[0042] (Eighth form) The adjacent planes in the circumferential direction are connected by a partial cylindrical surface. The aforementioned partial cylindrical surface and the inner circumferential surface of the main body are slidable. A seventh form of safety valve characterized by the following: [Explanation of Symbols]

[0043] 1. Safety valve 2 Main unit 24 Introductory path 25 valve seats 3 Valve body 33 shafts 33b Large diameter shaft section 4. Screw member 41 Cylindrical bore 42 Engagement holes 5. Coil spring CL gap channel IM intermediate channel L axis

Claims

1. A body comprising a fluid introduction passage and a valve seat formed around the inner end of the introduction passage, A fixing member having an opening that communicates with the outside and fixed to the main body, A valve body that can move closer to or further away from the valve seat, A locking portion disposed between the valve body and the fixing member, The valve body is biased toward the valve seat side relative to the fixing member by a coil spring, When the pressure in the introduction passage exceeds the valve opening pressure, the valve body separates from the valve seat against the biasing force of the coil spring, allowing the fluid in the introduction passage to flow into the gap passage between the valve body and the main body. The locking portion is sandwiched between the displaced valve body and the fixing member, thereby maintaining the axial distance between the valve body and the fixing member, and making it possible to form an intermediate passage between the valve body and the fixing member that connects the gap passage and the opening. The locking portion is a part of a shaft disposed on the valve body at a position shifted radially from the center of the valve body. The shaft comprises a first shaft portion, a large-diameter shaft portion, and a second shaft portion having a smaller diameter than the large-diameter shaft portion, with the large-diameter shaft portion being the locking portion. A safety valve characterized by the following features.

2. The first shaft portion is press-fitted into the mounting opening of the valve body. The safety valve according to feature 1.

3. The second shaft portion is inserted into the through hole of the fixing member so as to be displaceable relative to the safety valve in the axial direction, When the valve body is displaced toward the fixed member, the state in which the second shaft portion protrudes from the through hole can be visually observed from outside the safety valve. The safety valve according to feature 1.

4. Multiple shafts are attached to the valve body. A safety valve according to any one of claims 1 to 3.

5. The valve body has a substantially polygonal cylindrical shape with a plurality of planes along the circumferential direction, and the gap flow path is formed between the planes and the inner circumferential surface of the main body. The safety valve according to feature 1.

6. The adjacent planes in the circumferential direction are connected by a partial cylindrical surface. The aforementioned partial cylindrical surface and the inner circumferential surface of the main body are slidable. The safety valve according to feature 5.

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