JP6525356B2 - Check valve and refrigeration cycle device - Google Patents

Description

  The present invention relates to a check valve and a refrigeration cycle apparatus.

  The check valve has a function of flowing the fluid in only one direction, and is used, for example, in a refrigeration cycle apparatus. Inside the check valve, a valve body movable in the vertical direction is provided. In the forward flow, the upward movement of the valve opens the flow path and allows the fluid to pass. In the reverse flow, the valve moves downward to block the flow path and the fluid does not flow.

  The vertical movement of the valve body utilizes gravity and lift by fluid. In the case of the forward flow, if the flow rate is appropriate, gravity <lift, and the valve element is located near the upper end within the movable range. When the flow rate is gradually decreased from that state, the position does not change much more than the vicinity of the upper end for a while, but the valve position gradually decreases thereafter. And, even if the flow of the fluid is steady (a stable state where there is no discharge pulsation of a compressor or the like), the fluid slightly vibrates up and down. When the flow rate is further reduced, the vertical vibration increases and finally the check valve vibrates or generates noise because the valve body (lower end of the valve body) vibrates up and down while colliding with the valve box. Sometimes. This phenomenon is called chattering and is not uncommon in a particular small flow range.

  Further, in the refrigeration cycle apparatus, the efficiency has been improved in recent years, and the check valve is forced to reduce the pressure loss in the forward flow. Therefore, low pressure loss may be realized by using a check valve larger than the appropriate size. However, the use of a large check valve increases the flow rate range where chattering occurs. Therefore, the ratio of the range in which chattering occurs in the flow rate range of the refrigeration cycle apparatus increases. In order to suppress chattering, it is necessary to stop the operation in that range, which results in intermittent operation. The period efficiency is highly dependent on the low load side, and there is a possibility that the period efficiency may be significantly reduced if intermittent operation is performed at low load.

  With regard to such a problem, for example, in the technology disclosed in Patent Document 1, in order to suppress chattering of the check valve, attention is paid to the weight reduction of the valve body. That is, the gravity acting on the valve body is reduced, and chattering can be suppressed even if the lift to overcome it is small (even at a low flow rate).

  Further, Patent Document 2 focuses on the change rate of the flow passage area when the valve body is displaced in the vicinity of the valve seat, and suppresses the change rate of the flow passage area when the valve body moves upward from the seating position. Such a configuration is disclosed. It is disclosed that the generation | occurrence | production range of chattering is reduced by suppressing a lift reduction by this.

  Furthermore, Patent Document 3 discloses a technology capable of configuring a check valve regardless of the direction of gravity by using an elastic force obtained by providing a spring instead of gravity. When gravity is used, the check valve can be provided only in a mode in which the check valve is closed when flowing in the same direction as the gravity, but the refrigerant can flow regardless of gravity if it is an elastic force by a spring. .

JP, 2009-222097, A JP, 2006-200552, A JP, 2014-238147, A

  However, although the technique disclosed in Patent Document 1 and the technique disclosed in Patent Document 2 take measures against chattering against vertical changes of the valve body, they may be insufficient. The vibration mode of the valve body includes not only vertical vibration but also vibration in the posture direction generated by the radial clearance. Radial clearance is always required for the valve body to move up and down. However, since the flow rate range of the vibration in the posture direction is smaller than the chattering in the vertical direction, it seems that the suppression measures are not taken.

  Further, in the technology disclosed in Patent Document 3, providing a spring increases the number of parts and thus increases the assembly cost and the processing cost, and therefore is not desirable as a low cost check valve. There is also a risk when the spring breaks.

  The present invention is made in view of the above, and it aims at providing a nonreturn valve which can control chattering entirely, without relying on a spring.

  In order to achieve the above-mentioned object, the check valve of the present invention is disposed in a cylindrical valve box, a valve seat provided coaxially with the valve box, and the valve box. And a valve body movable in the axial direction of the box and capable of contacting the valve seat, wherein the valve body is formed with a pressure receiving surface on the surface facing the valve seat, and the pressure receiving surface is the first The first surface is formed farther from the valve seat than the center of gravity of the valve body.

  According to the present invention, chattering can be entirely suppressed without relying on a spring.

It is a longitudinal cross-sectional view of the non-return valve of the valve closing state of Embodiment 1 of this invention. It is a longitudinal cross-sectional view of the non-return valve of the valve opening state of Embodiment 1 of this invention. It is a side view of a valve body. It is a top view of the valve body seen from arrow IV of FIG. It is the bottom view seen from the arrow V of FIG. It is sectional drawing by the VI-VI line of FIG. It is a figure explaining the state which the valve body inclined from the perpendicular direction regarding this Embodiment 1. FIG. Figure 8 It is a figure explaining the state which the valve body inclined from the perpendicular direction regarding a comparative example. FIG. 7 is a view of the same aspect as FIG. 6 regarding the second embodiment. It is a figure of the same aspect as FIG. 6 regarding this Embodiment 3. FIG. It is a figure which shows the outline | summary of the refrigerating-cycle apparatus of this Embodiment 4. FIG.

  Hereinafter, embodiments of the present invention will be described based on the attached drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

Embodiment 1
FIG. 1 is a longitudinal sectional view of a check valve in a closed state according to the first embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a check valve in the open state according to the first embodiment of the present invention. is there. The check valve 1 is provided inside the target pipe 3. The check valve 1 is disposed in the cylindrical valve case 5, the valve seat 15 coaxially provided to the valve case 5, and the valve case 5, and is movable in the axial direction of the valve case 5 And a valve body 7 capable of contacting the valve seat 15. The upper side of the drawing of FIGS. 1 and 2 is the upper side at the time of actual installation, and the lower side of the drawing is the lower side of the actual installation.

  At the lower part of the valve box 5, a fluid inlet 9 is provided. In addition, a fluid outlet 11 is provided at the top of the valve box 5. The valve body 7 is vertically movably provided between the inlet 9 and the outlet 11 inside the valve box 5.

  FIG. 3 is a side view of the valve body 7 and shows the valve body from the same direction as FIGS. 1 and 2. FIG. 4 is a plan view of the valve body as viewed from the arrow IV of FIG. FIG. 5 is a bottom view seen from the arrow V of FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG.

  The valve body 7 has a substantially cylindrical outer shape. A plurality of (four in the illustrated example) convex portions 13 are provided on the outer peripheral surface of the valve body 7. The convex portions 13 respectively protrude outward in the radial direction from the outer peripheral surface of the valve body 7. Each of the convex portions 13 extends in the vertical direction at a predetermined height. The plurality of convex portions 13 are arranged at equal angular intervals in plan view. That is, each of the four convex portions 13 is separated by 90 degrees from the adjacent convex portion 13.

  The valve body 7 is guided by the convex portion 13 in the opening and closing direction. Further, when the valve is open, the fluid flows through the circumferential direction between the convex portions 13. In FIGS. 1 and 2, in order to express that there is a clearance between the tip of the convex portion 13 and the valve box 5, the state between the convex portion 13 and the valve box 5 is intentionally used. Exaggeratedly illustrated.

  The valve box 5 is provided with an annular valve seat 15. The lower end portion of the valve body 7 abuts (contacts) the valve seat 15 of the valve case 5 to close the flow path from the inlet 9 to the outlet 11.

  A recess 17 is provided on the inlet 9 side of the valve body 7. The recess 17 opens toward the inlet 9. The bottom surface 17 a is present in the recess 17. Also, there is an upper surface 17 b so as to face the bottom surface. The bottom and top surfaces do not have to be flat, and may be curved or conical. In the valve body 7, a pressure receiving surface is formed on the surface facing the valve seat (surface on the valve seat side). The pressure receiving surface is divided into a first surface 7a and a second surface 7b. The first surface 7a is the bottom surface 17a described above, and is formed farther from the valve seat 15 than the second surface 7b and closer to the central axis of the valve body 7 than the second surface 7b. .

  The center of gravity X of the entire valve body 7 is located inside the recess 17 as viewed in the vertical cross section of FIGS. 1, 2 and 6. The action point Y of the lift force B (force replaced with a single force) acting on the entire valve body 7 is higher than the center of gravity X of the entire valve body 7 in the vertical cross sections of FIG. 1, FIG. 2 and FIG. positioned. The first surface 7 a is formed farther than the center of gravity X of the valve body 7 with respect to the valve seat 15. Accordingly, the point of action Y of the lift force B acting on the entire valve body 7 is located forward of the center of gravity X of the entire valve body 7 in the advancing direction of the valve opening operation of the valve body 7.

Here, the point of action of the lift will be described. The refrigerant enters from below the check valve and exits from above. Since a pressure loss occurs in this process, the pressure in the lower part of the check valve is always larger than that in the upper part of the check valve, and a lift is generated on the valve body 7 upward. In particular, due to the configuration of the check valve, the pressure loss before and after refrigerant passes through the valve body is large. Furthermore, when the distance between the valve body and the valve seat is short, in which chattering occurs, the pressure loss before and after that is large. Therefore, the lower side of the valve body can be roughly divided into the high pressure side and the upper side as the low pressure side.
At this time, the bottom surface 17a of the valve body is on the high pressure side, and the upper surface 17b of the valve body is on the low pressure side, and a pressure difference between the two surfaces causes lift. (Strictly speaking, lift pressure and its point of action are determined as a result of handling the pressure of the refrigerant as a vector across the surface of the valve body and dividing it into areas. However, the valve body is roughly divided into high pressure side and low pressure side The lift force determined by the product of the pressure difference between the bottom surface of the valve body and the upper surface of the valve body and the pressure receiving area, and the lift action point determined as the center of the bottom surface of the valve seat can be said to be similar to the strictly determined one. )

  The operation of the check valve according to Embodiment 1 configured as described above will be described in comparison with a comparative example. FIG. 7 is a view of the same aspect as FIG. 6 regarding the first embodiment and is a view for explaining a state where the valve body is inclined from the vertical direction. FIG. 8 is a view of the same aspect as FIG. 7 regarding the comparative example, and is a view for explaining a state where the valve body is inclined from the vertical direction. 7 and 8 both illustrate the inclination mode in an exaggerated manner for the sake of clarity.

  As shown in FIG. 8, in the comparative example, since the recess is not provided in the valve body, the acting surface of the lift is the lower end surface of the valve body. That is, the point of action of the lift force B (a force replaced by a single force) is at a position lower than the center of gravity on which the gravity G acts. For this reason, gravity and lift are vectors facing each other, and because of radial clearance, once inclination occurs, overturning moment Mo is generated in the inclined direction. Once inclined, the valve body contacts the inner side surface of the check valve because the moment acts to further incline. Furthermore, when contact occurs, the valve body receives a reaction force from the inner side surface of the check valve in an action-reaction relationship, and the valve body is inclined in the reverse direction. By repeating such contact, the vibration accompanying the attitude | position change of a valve body continues. This phenomenon becomes more pronounced by reducing the weight of the valve body in order to suppress chattering in the vertical direction, with a decrease in the moment of inertia caused by the reduction in weight.

  On the other hand, in the first embodiment, the recess 17 is provided in the valve body 7. The lift generated in the valve in the case of the flow in the valve opening direction is due to the pressure difference generated in the valve, so the lift generation surface is above the comparative example having no recess. The acting surface of the lift is above the center of gravity, and lift is generated upward. That is, as described above, the point of action Y of the lift B is located above the center of gravity X. For this reason, in the first embodiment, gravity and lift are vectors on the opposite sides, and even if inclination occurs once due to radial clearance, a recovery moment Mr is generated to return the inclined direction. . Therefore, even if some irregular situation occurs and the valve body is inclined, a moment is generated to try to recover it, and the movement is attenuated and disappears. Therefore, chattering in the posture direction is less likely to occur.

  In addition, since a lighter one can flow the refrigerant against gravity even at a low flow rate, a lighter weight is required. If a suitable example is shown, a valve body can be comprised with resin. In addition, as for a refrigerating cycle device, connecting various parts by copper piping is common. Therefore, the valve box 5 for housing the valve body 7 may be made of metal such as copper or brass in consideration of assemblability. Although the valve body 7 slides in the valve box 5, the wear resistance is improved by combining the valve body (resin) and the main body (metal) with different kinds of substances.

  As described above, according to the first embodiment, chattering can be entirely suppressed without relying on a spring.

Second Embodiment
Next, the second embodiment will be described based on FIG. FIG. 9 is a view of the same aspect as FIG. 6 regarding the second embodiment. The second embodiment is the same as the above-described first embodiment except for the parts described below.

  The valve body 107 of the second embodiment is composed of a first member 121 and a second member 123. As an example, the second member 123 is located at the lower end of the first member 121. When the valve is closed, the second member 123 abuts on the valve seat 15.

  The center of gravity of the second member 123 is below the center of gravity of the first member 121. The density of the second member 123 is larger than the density of the first member 121.

  Also in the second embodiment configured as described above, chattering can be entirely suppressed without relying on a spring as in the first embodiment. Furthermore, in the second embodiment, since the center of gravity of the entire valve body 107 is located below the center of gravity of the entire valve body 7 of the first embodiment, the distance between the application points of gravity and lift increases. As compared with the same posture, the recovery moment is further increased, and the suppression effect of the chattering in the posture direction is further enhanced.

Third Embodiment
Next, the third embodiment will be described based on FIG. FIG. 10 is a view of the same aspect as FIG. 6 regarding the third embodiment. The third embodiment is the same as the first embodiment or the second embodiment described above except for parts described below.

  The valve body 207 is composed of a first member 121 and a second member 123. As an example, the second member 123 is located at the lower end of the first member 121. When the valve is closed, the second member 123 abuts on the valve seat 15. The center of gravity of the second member 123 is below the center of gravity of the first member 121. The density of the second member 123 is larger than the density of the first member 121. The first member 121 and the second member 123 form a recess 17 similar to the recess of the first embodiment described above.

  In the recess 17, a porous body 225 is provided. The porous body 225 is made of, for example, a plastic sintered porous body, a foam plastic (cell continuous type), or the like. The recess 17 is open at the lower end surface of the valve body 207, and the lower end of the porous body 225 is substantially aligned with the lower end surface of the valve body 207 described above.

  Also in the third embodiment configured as described above, the same advantage as the corresponding first embodiment or second embodiment is obtained. Furthermore, in the third embodiment, the following advantages can be obtained. The surface of the porous body opens into the check valve in the space on the low pressure side in the reverse flow. For this reason, the center of gravity is lowered as compared with the case where there is no porous body. As the center of gravity decreases, the distance between the gravity and lift acting points increases. Therefore, when compared in the posture of the same inclination, since the recovery moment mentioned above is further increased, chattering in the posture direction is suppressed. Further, in the present invention, it is important to provide a recess because of the relationship between gravity and lift. On the other hand, when the recess is provided, the center of gravity tends to rise. In addition, when the recess is provided, the strength tends to decrease accordingly. With respect to such contradictory circumstances, in the third embodiment, by providing the porous body, it becomes possible to simultaneously obtain the three advantages of obtaining the recovery moment, lowering the center of gravity and improving the strength. There is.

  Although the illustrated example of FIG. 10 is an example in which the feature of the third embodiment is combined with the second embodiment, the feature of the third embodiment may be combined with the first embodiment for implementation. it can.

Fourth Embodiment
Next, the fourth embodiment will be described based on FIG. FIG. 11 is a diagram showing an outline of the refrigeration cycle apparatus of the fourth embodiment. As an example of the refrigeration cycle apparatus 51, an air conditioner can be mentioned. The refrigeration cycle apparatus 51 includes a compressor 53, a heat source side heat exchanger 55, a pressure reducing unit 57, and a use side heat exchanger 59. As an example of the pressure reducing portion 57, an expansion valve can be mentioned. Further, in the cooling operation shown by the arrows, the heat source side heat exchanger 55 functions as a condenser, and the use side heat exchanger 59 functions as an evaporator.

  The check valve of the present invention is provided at the outlet of the compressor 53 during the cooling operation (a position between the outlet of the compressor 53 and the inlet of the heat source side heat exchanger 55 and very close to the outlet of the compressor 53). It is provided. Specifically, this check valve is any one of the check valves 1 of the first to third embodiments described above.

  Also in the refrigeration cycle apparatus of the fourth embodiment, the operation and effects of the corresponding first to third embodiments can be obtained.

  While the contents of the present invention have been specifically described with reference to the preferred embodiments, various modifications can be made by those skilled in the art based on the basic technical concept and teaching of the present invention. It is self-explanatory.

  The recess may be open downward, and the opening area of the recess may be smaller than the cross-sectional area of the hollow portion.

  Reference Signs List 1 check valve, 5 valve box, 7, 107, 207 valve body, 7a first surface, 7b second surface, 9 inlet, 11 outlet, 17 recess, 51 refrigeration cycle device, 53 compressor, 55 heat source side Heat exchanger, 57 pressure reduction unit, 59 utilization side heat exchanger, 121 first member, 123 second member, 225 porous body 225.

Claims (3)

A cylindrical valve box having an axis in the vertical direction;
A valve seat provided coaxially to the valve box;
It is disposed in the valve box, and by moving upward in the axial direction of the valve box, a flow path flowing from the lower side to the upper side is opened, and the axial direction moves downward of the valve box to contact the valve seat. And a valve body for closing the flow passage.
The valve body has a pressure receiving surface formed on the side facing the valve seat,
The pressure receiving surface is divided into a first surface and a second surface,
It said first surface is formed farther than the center of gravity of the valve body relative to the valve seat,
The valve body has a first member and a second member,
The center of gravity of the second member is below the center of gravity of the first member,
The density of the second member is greater than the density of the first member,
Check valve. The first surface is formed farther to the valve seat than the second surface and closer to the central axis of the valve body than the second surface.
The check valve of claim 1. A compressor, the check valve according to claim 1 or 2 , the heat source side heat exchanger, the pressure reducing unit, the use side heat exchanger,
Refrigeration cycle equipment.

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