Valve device and refrigeration system comprising same

Abstract

The present application discloses a valve device and a refrigeration system comprising same. The valve device comprises a valve seat, a first switching device and a second switching device, wherein a main fluid channel and a pressure relief channel are provided in the valve seat. In the present application, the main fluid channel and the pressure relief channel, which are independently connected or disconnected, are arranged in the valve device, such that the second switching device does not affect the structure and function of the first switching device. The valve device can limit the unidirectional flow of a fluid from a valve inlet to a valve outlet, and can also realize the pressure relief flow of the fluid from the valve outlet to the valve inlet, thereby balancing the pressure between the valve inlet and the valve outlet. Therefore, the valve device of the present application not only has a simple structure, but is also particularly suitable for application scenarios with pressure fluctuations. In addition, since the second switching device is disposed inside a valve stem, it is unnecessary to greatly change the external structure and connection relationship of an existing valve device.

Description

Valve device and refrigeration system comprising same TECHNICAL FIELD

[0001] The present application relates to the field of refrigeration systems, and in particular to a valve device and a refrigeration system comprising same. BACKGROUND

[0002] Some refrigeration systems include a valve device connected between an evaporator and a compressor. The valve device is generally a one-way valve device that restricts the flow of refrigerant gas from the outlet of the evaporator to the suction port of the compressor to prevent the compressor from reversing. When the compressor is a screw compressor, the compressor includes compression volumes that move from the suction port to the discharge port of the compressor, and the volume of the compression volumes gradually decreases so that the pressure of the compression volumes gradually increases.

[0003] Under some operating conditions, the refrigeration system needs to be frequently turned on and off, which causes pressure fluctuations between the suction port and the discharge port of the compressor. When the refrigeration system is stopped, the compressor is immediately stopped, which causes the suction port of the compressor to possibly communicate with the compression volumes inside the compressor, which have a higher pressure, and causes the pressure at the outlet of the valve device to be high. If the refrigeration system is turned on again at this time to restart the compressor, the high pressure at the suction port of the compressor will cause the starting load of the compressor to be high, which in turn can cause the compressor to fail to start normally. SUMMARY

[0004] The present application provides, in a first aspect, a valve device comprising a valve seat, a first switch device, and a second switch device. The valve seat has a valve inlet and a valve outlet, and a main fluid passage and a pressure relief passage are provided in the valve seat, each of the main fluid passage and the pressure relief passage independently communicating the valve inlet and the valve outlet. The first switch device is provided in the main fluid passage and is configured to be able to be closed to disconnect the main fluid passage or opened to connect the main fluid passage. The second switch device is provided in the pressure relief passage and is configured to be able to be closed to disconnect the pressure relief passage or opened to connect the pressure relief passage. The first switch device and the second switch device are arranged such that, when the first switch device is opened, fluid is allowed to flow through the main fluid passage, and when the first switch device is closed, the second switch device is controllably opened to allow fluid to flow through the pressure relief passage.

[0005] According to the first aspect described above, the first switch device is arranged to be opened unidirectionally based on the pressure difference between the valve inlet and the valve outlet to allow the fluid to flow unidirectionally from the valve inlet to the valve outlet through the main fluid passage. When the pressure of the valve inlet is greater than the pressure of the valve outlet and the pressure difference between the two is greater than a first threshold value, the first switch device is opened, otherwise the first switch device is closed.

[0006] According to the first aspect, the second switch device is configured to be opened unidirectionally based on a pressure difference between the valve inlet and the valve outlet to allow the fluid to flow unidirectionally from the valve outlet to the valve inlet through the pressure relief passage. The second switch device is opened unidirectionally when the pressure of the valve outlet is greater than the pressure of the valve inlet and the pressure difference between the two is greater than a second threshold value, otherwise the second switch device is closed.

[0007] According to the first aspect, the valve seat comprises a valve stem, the pressure relief passage is defined in the valve stem, and the pressure relief passage forms a pressure relief inlet and a pressure relief outlet on the valve stem. The pressure relief inlet is in fluid communication with the valve outlet, and the pressure relief outlet is in fluid communication with the valve inlet. The second switch device is configured to allow the fluid to flow from the valve outlet to the pressure relief inlet, through the pressure relief passage to the pressure relief outlet, and finally out of the valve inlet when the second switch device is opened unidirectionally.

[0008] According to the first aspect, the second switch device comprises a sleeve and a valve core. The sleeve has an inwardly protruding shoulder with an inner sealing surface. The valve core is arranged in the sleeve and is configured to move linearly, the valve core has an outer sealing surface, and the inner sealing surface and the outer sealing surface are configured to contact each other. The pressure relief inlet and the pressure relief outlet are arranged on opposite sides of the shoulder, so that as the valve core moves linearly, the outer sealing surface of the valve core can abut the inner sealing surface of the shoulder to disconnect the pressure relief passage. And the outer sealing surface of the valve core can be away from the inner sealing surface of the shoulder to connect the pressure relief passage.

[0009] According to the first aspect, the second switch device further comprises a second damping element connected between the valve core and the sleeve, the second damping element is configured to apply a holding force to the valve core to keep the outer sealing surface of the valve core abutting the inner sealing surface of the shoulder of the sleeve. The holding force is configured to correspond to the second threshold value of the pressure difference between the valve outlet and the valve inlet.

[0010] According to the first aspect, the sleeve is configured to rotate in the valve stem. The sleeve has a flow regulating groove that penetrates both the inner and outer sides of the sleeve, and the flow regulating groove has different widths in the circumferential direction, so that as the sleeve rotates, the flow regulating groove can be in fluid communication with the pressure relief outlet at different flow areas, thereby adjusting the flow rate of the fluid flowing out of the pressure relief outlet.

[0011] According to the first aspect, the second switch device further comprises a rotating block, a sealing member and a top cover. The rotating block is connected with the sleeve to enable the rotating block to rotate the sleeve. The top cover is sealingly connected to the rotating block via the sealing member, and the top cover is fixedly connected with the valve stem. The rotating block has a rotating knob, and the top cover is provided with at least one limiting pin configured to limit the rotating position of the rotating knob, so as to limit the rotating position of the sleeve.

[0012] According to the first aspect, the first switch device comprises a valve shaft, at least one valve flap and at least one first damping element and a blocking portion. The valve shaft is connected to the valve seat. The valve flap is pivoted to the valve shaft, the valve flap has a valve flap closed position and a valve flap open position, and the valve flap can rotate around the valve shaft between the valve flap closed position and the valve flap open position. The at least one first damping element is connected between the valve shaft and the corresponding valve flap, and the blocking portion is arranged on the inner wall of the valve seat, wherein the first damping element and the blocking portion together keep the valve flap in the valve flap closed position. When the valve flap is in the valve flap closed position, the valve flap abuts against the blocking portion of the valve seat to disconnect the main fluid passage, and when the valve flap is away from the blocking portion, the main fluid passage is connected.

[0013] According to the first aspect, the first damping element is configured to apply a holding force to each valve flap to keep the valve flap in the valve flap closed position, and the holding force of the first damping element is configured to correspond to a first threshold of the pressure difference between the valve inlet and the valve outlet.

[0014] The present application provides, in a second aspect, a refrigeration system comprising a compressor, an evaporator, a throttling device and a condenser arranged in a refrigerant circuit, and a valve device according to any one of the first aspect. The valve device is arranged between the evaporator and the compressor, wherein the valve inlet of the valve device is in fluid communication with the evaporator, and the valve outlet of the valve device is in fluid communication with the compressor. BRIEF DESCRIPTION OF DRAWINGS

[0015] FIG. 1A is a perspective view of a valve device according to an embodiment of the present application at one angle;

[0016] FIG. 1B is a perspective view of the valve device shown in FIG. 1A at another angle;

[0017] FIG. 1C is an elevation view of the valve device shown in FIG. 1A;

[0018] FIG. 1D is a side view of the valve device shown in FIG. 1A;

[0019] Figure 2A is a cross-sectional view of the valve device along line A-A in Figure 1C with the first switch device in a closed condition;

[0020] Figure 2B is a cross-sectional view of the valve device along line A-A in Figure 1C with the first switch device in an open condition;

[0021] Figure 3A is an exploded view of the valve device shown in Figure 1A at one angle;

[0022] Figure 3B is an exploded view of the valve device shown in Figure 1A at another angle;

[0023] Figure 3C is a cross-sectional view of the valve device along line B-B in Figure 1C;

[0024] Figure 4 is an exploded view of the second switch device in Figure 3A;

[0025] Figure 5A is a cross-sectional view of the second switch device in Figure 4 in a closed condition;

[0026] Figure 5B is a cross-sectional view of the second switch device in Figure 4 in an open condition;

[0027] Figure 6A is a cross-sectional view of the second switch device in Figure 4 in an open condition and at a minimum flow rate;

[0028] Figure 6B is a cross-sectional view of the second switch device in Figure 4 in an open condition and at a maximum flow rate;

[0029] Figure 7 is a schematic block diagram of a refrigeration system including the valve device shown in Figure 1A. DETAILED DESCRIPTION

[0030] Various embodiments of the application will be described in relation to the drawings detailed below, which constitute a part of this specification. It is to be understood that, although terms indicating directions, such as "front", "back", "upper", "lower", "left", "right", "top", "bottom", etc., are used in this application to describe various example structural parts and elements of this application, these terms are used herein only for the purpose of convenience of explanation, as determined based on the example orientation shown in the drawings. Since the embodiments disclosed in this application can be arranged in different directions, these terms indicating directions are only for illustration and should not be considered as limiting.

[0031] FIGS. 1A-1D show the detailed structure of the valve device 100 according to one embodiment of the present application, for showing the external structure of the valve device 100. Among them, FIG. 1A shows a perspective view of the valve device 100 from the front, FIG. 1B shows a perspective view of the valve device 100 from the back, FIG. 1C shows a front view of the valve device 100, and FIG. 1D shows a side view of the valve device 100. As shown in FIGS. 1A-1D, the valve device 100 includes a valve seat 101 having a valve inlet 102 and a valve outlet 103, and defining a main fluid passage 108. The valve seat 101 is generally cylindrical in shape, having a front end wall 113 and a rear end wall 114 at both ends, respectively, and the openings of the front end wall 113 and the rear end wall 114 form the valve inlet 102 and the valve outlet 103, respectively. The cylindrical portion of the valve seat 101 forms an annular wall 112, which defines the main fluid passage 108. The main fluid passage 108 is capable of fluidly connecting the valve inlet 102 and the valve outlet 103. The valve device 100 further includes a first switching device 110 for switching on or off the main fluid passage 108. In this embodiment, the first switching device 110 is configured to be opened unidirectionally based on the pressure difference between the valve inlet 102 and the valve outlet 103, to allow the fluid to flow unidirectionally from the valve inlet 102 through the main fluid passage 108 to the valve outlet 103, otherwise the first switching device 110 is closed. In some embodiments, the first switching device 110 is configured to have a first threshold value of the pressure difference. When the pressure of the valve inlet 102 is greater than the pressure of the valve outlet 103, and the pressure difference between the two exceeds the first threshold value, the first switching device 110 will automatically open, otherwise the first switching device 110 will automatically close.

[0032] In the present embodiment, the first switching device 110 comprises a valve shaft 105 and at least one valve flap 111. The valve shaft 105 is vertically connected to the annular wall 112 of the valve seat 101 and is located substantially at the middle of the valve seat 101. The valve flaps 111 are each pivotally connected to the valve shaft 105 to rotate around the valve shaft 105. Each valve flap 111 has a valve flap closed position and a valve flap open position, and rotates around the valve shaft 105 between the valve flap closed position and the valve flap open position. The first switching device 110 is closed when each valve flap 111 is in the respective valve flap closed position, and is opened when each valve flap 111 is in the respective valve flap open position. In the present embodiment, the at least one valve flap 111 comprises a pair of valve flaps 111, each of which is substantially a semicircular plate. The top and bottom of each valve flap 111 are pivotally connected to the valve shaft 105 by a mounting seat 115, respectively. When each valve flap 111 is in the respective valve flap closed position, the pair of valve flaps 111 are substantially flush and abut the inner wall of the valve seat 101 to disconnect the main fluid passage 108. Those skilled in the art can understand that the at least one valve flap can also comprise other numbers of valve flaps, which are arranged in a shape corresponding to the ability to disconnect or connect the main fluid passage 108.

[0033] The first switching device 110 further comprises a first damping element 104 arranged at the rear side of the valve flaps 111. The first damping element 104 is connected between the valve shaft 105 and the pair of valve flaps 111. When the valve flaps 111 are in their closed positions, the first damping element 104 can apply a holding force to the valve flaps 111 to keep the valve flaps 111 in the valve flap closed positions, which can hinder the valve flaps 111 from rotating from the valve flap closed positions to the valve flap open positions. The holding force is arranged corresponding to the first threshold value of the pressure difference of the first switching device 110.

[0034] The first switching device 110 further comprises a blocking portion 217 (see FIGS. 2A and 2B) arranged on the inner wall of the annular wall 112 of the valve seat 101, which in the present embodiment is a ring of protrusions protruding from the inner wall of the annular wall 112 into the main fluid passage 108. The blocking portion 217 is located at the front side of the valve flaps 111 and corresponds to the valve flap closed positions of the valve flaps 111, so that the blocking portion 217 cooperates with the first damping element 104 to keep the valve flaps 111 in their valve flap closed positions. The cooperation structure of the blocking portion 217 and the valve flaps 111 will be described in conjunction with FIGS. 2A and 2B.

[0035] In the present embodiment, the first switching device 110 further comprises a limiting rod 106 and a pair of limiting blocks 107. The limiting rod 106 is vertically connected to the annular wall 112 of the valve seat 101 and is located at the rear side of the valve shaft 105. The pair of limiting blocks 107 are arranged at the edges of the middle portions of the corresponding valve petals 111. When the valve petals 111 are rotated to their open positions, the limiting blocks 107 are capable of abutting against the limiting rod 106 to avoid the valve petals 111 from continuing to rotate in the opening direction, so as to make the first switching device 110 reach the maximum opening degree.

[0036] In the present application, the valve device 100 further comprises a valve stem 109 which is vertically connected to the annular wall 112 of the valve seat 101. The valve stem 109 is located at the valve inlet 102 and is located at the front side of the first switching device 110. The valve stem 109 defines a pressure relief passage 328 inside, which forms a pressure relief outlet 123 on the front side wall of the valve stem 109 and forms a pressure relief inlet 322 on the rear side wall of the valve stem 109 (see FIG. 3C). The pressure relief outlet 123 is in communication with the valve inlet 102, and the pressure relief inlet 322 is in communication with the valve outlet 103. Thus, the pressure relief passage 328 and the main fluid passage 108 are capable of respectively and independently communicating the valve inlet 102 and the valve outlet 103.

[0037] The valve device 100 further comprises a second switching device 320 which is arranged in the pressure relief passage 328 of the valve stem 109 for switching on or off the pressure relief passage 328. In the present embodiment, the second switching device 320 is also arranged to be opened in one direction based on the pressure difference between the valve inlet 102 and the valve outlet 103, so as to allow the fluid to flow from the valve outlet 103 into the pressure relief inlet 322, then unidirectionally flow through the pressure relief passage 328 to the pressure relief outlet 123, and then be discharged from the valve inlet 102, otherwise the second switching device 320 is closed. In some embodiments, the second switching device 320 is arranged to have a second threshold value of pressure difference. When the pressure of the valve outlet 103 is greater than the pressure of the valve inlet 102, and the pressure difference between the two is greater than the second threshold value, the second switching device 320 is automatically opened, otherwise the second switching device 320 is closed. In the present embodiment, the top of the valve stem 109 is further connected with a cover 116 for closing the pressure relief passage 328 from the top of the valve stem 109. The more specific structure of the second switching device 320 will be described in detail later.

[0038] Therefore, when the pressure of the valve inlet 102 is greater than the pressure of the valve outlet 103, and the pressure difference is greater than the first threshold, the first switching device 110 is opened, and the second switching device 320 is closed, to allow fluid to flow through the main fluid passage 108. And when the pressure of the valve outlet 103 is greater than the pressure of the valve inlet 102, and the pressure difference is greater than the second threshold, the first switching device 110 is closed, and the second switching device 320 is opened, to allow fluid to flow through the pressure relief passage 328. Otherwise, both the first switching device 110 and the second switching device 320 are closed. In this way, the pressure difference between the valve inlet 102 and the valve outlet 103 can be controlled within a certain range. It should be noted that the first threshold is calculated based on the pressure difference between the valve inlet 102 and the valve outlet 103, and the second threshold is calculated based on the pressure difference between the valve outlet 103 and the valve inlet 102, that is, both the first threshold and the second threshold are greater than 0.

[0039] It can be understood by those skilled in the art that in some embodiments, the first switching device 110 and the second switching device 320 can also be controlled by the control device to be opened or closed. It is only necessary to ensure that when the first switching device 110 is opened, fluid can be allowed to flow through the main fluid passage 108. And when the first switching device 110 is closed, the second switching device 320 can be controllably opened to allow fluid to flow through the pressure relief passage 328.

[0040] FIGS. 2A and 2B are used to illustrate the opening and closing process of the first switching device 110 in the valve device 100. FIG. 2A shows a cross-sectional view of the valve device 100 along the A-A line in FIG. 1C, in which the first switching device 110 is in a closed state. FIG. 2B shows a cross-sectional view of the valve device 100 along the A-A line in FIG. 1C, in which the first switching device 110 is in an open state. As shown in FIG. 2A, when the first switching device 110 is closed, each valve flap 111 is in a respective valve flap closed position, and the valve flap 111 is arranged in the main fluid passage 108 substantially perpendicular to the extension direction of the valve seat 101, so that the valve flap 111 can block the fluid flow. The circumferential edge outside each valve flap 111 abuts against the blocking portion 217, and the inner edge of each valve flap 111 abuts against the valve rod 109. Thus, the pair of valve flaps 111 blocks both sides of the main fluid passage 108, and the valve rod 109 blocks the middle of the main fluid passage 108, so that they collectively disconnect the main fluid passage 108. At this time, the pair of first damping elements 104 applies a holding force to the corresponding valve flap 111 to rotate the valve flap 111 forward, which pushes the valve flap 111 to keep abutting against the blocking portion 217 and the valve rod 109, thereby keeping the valve flap 111 in the valve flap closed position.

[0041] In the present embodiment, each valve disc 111 further comprises an inclined wall 218 arranged at the inner side edge of the valve disc 111, which extends from inside to outside in a front-to-back direction. The inclined wall 218 can facilitate that the front end of the inner side edge of the valve disc 111 can abut against the valve stem 109 in the middle, while the rear end of the inner side edge of the valve disc 111 can leave a mounting space for the valve shaft 105, and a rotating space for the valve disc 111. In the present embodiment, the inner side edges of the pair of valve discs 111 are spaced apart by a certain distance, so that the pressure relief inlet 322 can be arranged between the pair of valve discs 111. Thus, when the valve discs 111 are in the valve disc closed position, the pressure relief inlet 322 is not blocked by the valve discs 111, but can maintain fluid communication with the valve outlet 103.

[0042] When the pressure difference between the valve inlet 102 and the valve outlet 103 is greater than the first threshold value, the valve disc 111 can rotate to the left (i.e. to the opening direction) against the holding force of the first damping element 104, i.e. towards its valve disc open position, so that the valve disc 111 gradually leaves the blocking portion 217, so that the fluid can flow through the main fluid passage 108. The fluid pressure of the fluid acts on the valve disc 111, so that the valve disc 111 further rotates to the opening direction, which will cause the torque applied by the first damping element 104 to the valve disc 111 to gradually increase, until the valve disc 111 reaches the valve disc open position as shown in FIG. 2B.

[0043] As shown in FIG. 2B, when the first switching device 110 is open, each valve disc 111 is in the respective valve disc open position, and the valve disc 111 is arranged in the main fluid passage 108 substantially along the extension direction of the valve seat 101, so that the valve disc 111 no longer blocks the fluid flow, for example, in the direction indicated by the arrow in the figure, from the valve inlet 102 to the valve outlet 103. The stop block 107 of each valve disc 111 abuts against the left and right sides of the stop rod 106, to prevent the valve disc 111 from continuing to rotate to the opening direction. Under the action of the fluid pressure of the fluid, the valve disc 111 can be maintained in the valve disc open position.

[0044] When the pressure difference between the valve inlet 102 and the valve outlet 103 gradually decreases, the valve disc 111 rotates again to the valve disc closed position under the action of the torque of the first damping element 104. Until the valve disc 111 again abuts against the blocking portion 217, the valve disc 111 reaches the valve disc closed position as shown in FIG. 2A.

[0045] Thus, the first switching device 110 can be opened or closed based on the pressure difference between the valve inlet 102 and the valve outlet 103, so as to connect or disconnect the main fluid passage 108.

[0046] Figs. 3A-3C show more specific structures of the first switching device 110 in the valve device 100 and the general positions and structures of the second switching device 320. Among them, Fig. 3A shows an exploded view of the valve device 100 from a front-to-back perspective, Fig. 3B shows an exploded view of the valve device 100 from a back-to-front perspective, and Fig. 3C shows a sectional view of the valve device 100 along the line B-B in Fig. 1C. As shown in Figs. 3A-3C, the valve flap 111 is generally semicircular in shape, and the valve flap 111 protrudes forward at the edge to form an arc-shaped abutment wall 346 and a linear abutment wall 347. The rear side of the blocking portion 217 and the valve stem 109 are provided with a semicircular mating abutment wall 343 corresponding to the edge of the valve flap 111, which includes an arc-shaped blocking portion abutment wall 356 protruding further rearward from the rear end face of the blocking portion 217 and a linear valve stem abutment wall 357 protruding further rearward from the rear end face of the valve stem 109. The shape of the mating abutment wall 343 matches the edge shape of the valve flap 111. When the valve flap 111 is in the valve flap closed position, the arc-shaped abutment wall 346 abuts the blocking portion abutment wall 356, and the linear abutment wall 347 abuts the valve stem abutment wall 357, so that the valve flap 111 and the valve stem 109 jointly block in the main fluid passage 108, thereby disconnecting the main fluid passage 108.

[0047] Each valve flap 111 is pivoted to the valve shaft 105 by a pair of mounting seats 115. Specifically, a pair of mounting seats 115 of each valve flap 111 are connected to the top and bottom of the valve flap 111, respectively, and the mounting seats 115 of the pair of valve flaps 111 are staggered. The first damping element 104 is sleeved on the middle part of the valve shaft 105 and is arranged to apply a holding force to the pair of valve flaps 111. In this embodiment, the first damping element 104 is a torsion spring, and the two ends of the torsion spring abut to the pair of valve flaps 111, respectively, to apply substantially the same pre-tightening force (i.e., holding force) to the pair of valve flaps 111, so that the pair of valve flaps 111 can be rotated synchronously against the holding force of the torsion spring.

[0048] The valve shaft 105 and the limit rod 106 are both vertically arranged in the middle of the valve seat 101, and the valve shaft 105 is located at the rear side of the valve stem 109, and the limit rod 106 is arranged at the rear side of the valve shaft 105. In the present embodiment, the valve device 100 further comprises a pair of connecting blocks 341. The valve shaft 105 and the limit rod 106 are connected side by side between the pair of connecting blocks 341. The top and bottom of the inner wall of the valve seat 101 are recessed to form a pair of connecting grooves 342, which are matched in shape and size with the pair of connecting blocks 341. By connecting the pair of connecting blocks 341 to the pair of connecting grooves 342, for example, by detachable connection such as fastening connection, the valve shaft 105 and the limit rod 106 can be connected to the valve seat 101. Those skilled in the art can understand that through the connecting blocks and the connecting grooves, the connection and disconnection of the valve shaft 105 and the limit rod 106 with the valve seat 101 can be facilitated. In other embodiments, the valve shaft 105 and the limit rod 106 can also be connected to the valve seat 101 by other means.

[0049] The pressure relief passage 328 is arranged at the top of the valve stem 109, and the cover 116 closes the pressure relief passage 328 from the top of the valve stem 109, so that the fluid can only flow from the pressure relief passage 328. The pressure relief inlet 322 of the pressure relief passage 328 is arranged on the rear end face of the valve stem 109 and located between the pair of valve stem abutting walls 357. When the valve flap 111 is in the valve flap closed position, the main fluid passage 108 can be disconnected, but the valve flap 111 does not block the pressure relief inlet 322. When the valve flap 111 is in the valve flap open position, the valve flap 111 is away from the valve stem 109, and does not block the pressure relief inlet 322 on the valve stem 109. Therefore, the pressure relief inlet 322 can maintain fluid communication with the valve outlet 103 regardless of whether the first switch device 110 is open or closed. And the pressure relief outlet 123 is arranged on the front side wall of the valve stem 109, so it can also maintain fluid communication with the valve inlet 102. Thus, the pressure relief passage 328 and the main fluid passage 108 can each independently fluidly communicate the valve inlet 102 and the valve outlet 103.

[0050] The second switching device 320 is provided in the pressure relief passage 328 and is configured to be able to communicate or shut off the pressure relief passage 328 based on a pressure difference between the pressure relief inlet 322 and the pressure relief outlet 123, i.e. a pressure difference between the valve outlet 103 and the valve inlet 102. In the present embodiment, the second switching device 320 includes a sleeve 321 and a valve core 324. The sleeve 321 is hollow and extends in the vertical direction. The valve core 324 is provided in the sleeve 321 and is able to move linearly in the vertical direction in the sleeve 321. In the present embodiment, the valve core 324 has a valve core open position at the highest position and a valve core closed position at the lowest position, and the valve core 324 moves linearly between the valve core open position and the valve core closed position. With the linear movement of the valve core 324, the valve core 324 is able to engage with an inner wall of the sleeve 321 at the valve core closed position or leave the inner wall of the sleeve 321 at the valve core open position. The pressure relief outlet 123 and the pressure relief inlet 322 are respectively provided on opposite sides of the engagement position of the valve core 324 with the sleeve 321, so that the pressure relief outlet 123 and the pressure relief inlet 322 are shut off when the valve core 324 engages with the inner wall of the sleeve 321, and the pressure relief outlet 123 and the pressure relief inlet 322 are communicated when the valve core 324 leaves the inner wall of the sleeve 321.

[0051] The second switching device 320 further includes a second damping element 344 connected between the valve core 324 and the sleeve 321 to apply a holding force to the valve core 324 for pushing the valve core 324 towards the inner wall of the sleeve 321 to keep the second switching device 320 in the closed state. The holding force is set corresponding to the second threshold value of the pressure difference of the second switching device 320.

[0052] The second switching device 320 further includes a flow regulating groove 348 provided on the cylinder wall of the sleeve 321 and extending through the inner and outer sides of the sleeve 321. The flow regulating groove 348 has a height substantially aligned with the pressure relief outlet 123 and extends in the circumferential direction. In the present embodiment, the flow regulating groove 348 has different widths in the circumferential direction, so that the flow regulating groove 348 is able to communicate with the pressure relief outlet 123 in different flow areas as the sleeve 321 rotates to different positions, thereby regulating the flow of fluid from the pressure relief outlet 123. In the present embodiment, the second switching device 320 further includes a rotating block 325 connected with the sleeve 321 and located at the top of the sleeve 321, so that the rotating block 325 is able to rotate to drive the sleeve 321 to rotate.

[0053] Thus, the second switching device 320 is not only able to open or close based on the pressure difference between the valve inlet 102 and the valve outlet 103, but also able to regulate the flow of fluid in the pressure relief passage 328 by controlling the rotation of the sleeve 321.

[0054] Fig. 4 is an exploded view of the second switching device 320 in Fig. 3A, for showing more specific structure of the second switching device 320. As shown in Fig. 4, the inner wall of the bottom of the sleeve 321 has an inwardly protruding shoulder 451, which defines an opening 573 (see Fig. 5A). The pressure relief outlet 123 and the pressure relief inlet 322 are respectively arranged on the upper and lower sides of the shoulder 451, to communicate or disconnect the pressure relief passage 328 by opening or closing the opening 573. The top of the shoulder 451 forms an inner sealing surface 452 that gradually inclines inwardly from top to bottom. The bottom of the spool 324 has an outer sealing surface 453 that is complementary to the inner sealing surface 452. When the spool 324 is in its spool closed position, the outer sealing surface 453 of the spool 324 can abut the inner sealing surface 452 of the shoulder 451 of the sleeve 321, to disconnect the pressure relief passage 328 in the sleeve 321. When the spool 324 is in its spool open position, the outer sealing surface 453 of the spool 324 is away from the inner sealing surface 452 of the sleeve 321, to communicate the pressure relief passage 328.

[0055] The second switching device 320 further includes a fixing nut 445, which is fixedly connected in the sleeve 321. In the present embodiment, the fixing nut 445 is fastened in the sleeve 321 by engaging threads, to ensure that the fixing nut 445 cannot move up and down in the sleeve 321. In the present embodiment, the second damping element 344 is a spring, one end of which abuts to the fixing nut 445, to be connected to the sleeve 321 through the fixing nut 445. The inside of the spool 324 has an inwardly protruding annular boss, and the other end of the spring abuts to the annular boss in the spool 324, to elastically connect the second damping element 344 between the sleeve 321 and the spool 324. The second damping element 344 is arranged to apply a certain pre-tightening force (i.e. holding force) to the spool 324 when the spool 324 is in its spool closed position, to ensure that the outer sealing surface 453 of the spool 324 can abut the inner sealing surface 452 of the sleeve 321. In the present embodiment, this pre-tightening force is the second threshold value. When the pressure difference between the valve outlet 103 and the valve inlet 102 is large enough, the fluid pushes the spool 324 upward from below to overcome the elastic force of the second damping element 344.

[0056] The rotating block 325 is substantially cylindrical in shape, and is connected above the sleeve 321 to enclose the valve core 324, the second damping element 344 and the fixing nut 445 in the sleeve 321. The bottom of the rotating block 325 is connected with the top of the sleeve 321 to enable the rotating block 325 to drive the sleeve 321 to rotate. In the embodiment, the top edge of the sleeve 321 has a pair of symmetrically arranged notches 461 recessed downward, and the bottom of the rotating block 325 has a strip-shaped protrusion 462 matching the shape of the notches 461 to enable the rotating block 325 to drive the sleeve 321 to rotate. In other embodiments, the rotating block 325 can also drive the sleeve 321 to rotate through other matching structures.

[0057] The top of the rotating block 325 is connected with an engaging column 464 and a rotating knob 463. The engaging column 464 is fixedly connected to the end face of the top of the rotating block 325 and protrudes upward along the axial direction. In the embodiment, the engaging column 464 is a square prism to facilitate the engagement of the engaging column 464 with an external tool, and the driving of the engaging column 464 to rotate by the external tool, thereby driving the rotating block 325 to rotate. The rotating knob 463 is a fan ring shape, and is connected to the end face of the top of the rotating block 325 and protrudes from the circumferential side wall of the rotating block 325. The rotating knob 463 is used to limit and indicate the position of the rotating block 325 in the circumferential direction.

[0058] The second switch device 320 further comprises a ring-shaped sealing member 465 and a top cover 426, which is connected above the rotating block 325 through the sealing member 465, and the top cover 426 is fixedly connected with the inner wall of the valve stem 109, so that the top cover 426 does not rotate with the rotation of the rotating block 325. Specifically, the sealing member 465 is sleeved on the outer side of the rotating block 325, and the top cover 426 is arranged above the rotating block 325. The bottom edge of the top cover 426 abuts against the sealing member 465, and the top cover 426 is arranged above the rotating block 325. The top of the top cover 426 has a through hole 468, and the engaging column 464 and the rotating knob 463 pass through the through hole 468 to above the top cover 426. The top of the top cover 426 further comprises at least one limiting pin 467, which is used to block the rotating range of the rotating knob 463 to limit the rotating position of the rotating knob 463. By arranging the limiting pin 467 at a predetermined position, the rotating position of the rotating knob 463 can also be indicated, thereby limiting and indicating the position of the rotating block 325 in the circumferential direction. In this embodiment, the at least one limiting pin 467 comprises two limiting pins 467, and the rotating knob 463 rotates between the two limiting pins 467. The two limiting pins 467 correspond to the positions of the maximum width and the minimum width of the flow adjusting groove 348, respectively. When the rotating knob 463 is rotated to be blocked by one of the two limiting pins 467, the rotating block 325 and the sleeve 321 can be rotated to the position of the maximum width or the minimum width of the flow adjusting groove 348, so that the corresponding maximum flow or minimum flow flows out from the pressure relief outlet 123.

[0059] FIGS. 5A and 5B are used to illustrate the opening and closing processes of the second switch device 320. FIG. 5A shows a sectional view of the second switch device 320 along the line B-B in FIG. 1C, in which the second switch device 320 is in a closed state. FIG. 5B shows a sectional view of the second switch device 320 along the line B-B in FIG. 1C, in which the second switch device 320 is in an open state. As shown in FIG. 5A, the valve core 324 comprises a cylinder portion 571 and a core portion 572, which are fixedly connected or integrally formed so as to move together. The inner wall of the cylinder portion 571 is inwardly protruded to form an annular stepped portion 574, and the bottom end of the second damping element 344 abuts against the stepped portion 574 to apply a pre-tightening holding force to the valve core 324. When the second switch device 320 is in a closed state, the valve core 324 is in a lowest valve core closed position. At this time, under the action of the holding force of the second damping element 344, the outer sealing surface 453 of the valve core 324 abuts against the inner sealing surface 452 of the sleeve 321 to close the opening 573 formed by the shoulder portion 451 of the sleeve 321, thereby disconnecting the pressure relief passage 328. However, the valve core 324 below still communicates with the pressure relief inlet 322 through the opening 573, and the flow adjusting groove 348 communicates with the pressure relief outlet 123.

[0060] When the pressure difference between the valve inlet 102 and the valve outlet 103 is greater than the second threshold value, the pressure difference between the pressure relief inlet 322 and the pressure relief outlet 123 is also greater than the second threshold value, so that the spool 324 can move upward, i.e. linearly move towards its spool opening position, against the holding force of the second damping element 344. The outer sealing surface 453 of the spool 324 gradually leaves the inner sealing surface 452 of the sleeve 321 to open the opening 573, allowing the fluid to flow from the pressure relief passage 328. Since the fixed nut 445 is fixedly connected to the inner wall of the sleeve 321, the second damping element abutting the fixed nut 445 elastically deforms, and the second damping element 344 applies an elastic force downward to the spool 324. The fluid pressure of the fluid acts on the bottom of the spool 324, pushing the spool 324 to move further upward, which will further compress the second damping element 344 to elastically deform, so that the downward elastic force of the second damping element 344 applied to the spool 324 gradually increases, until the spool 324 reaches the spool opening position as shown in FIG. 5B.

[0061] As shown in FIG. 5B, when the second switching device 320 is opened, the spool 324 is in the highest spool opening position. The top edge of the spool 324 abuts the fixed nut 445, so that the spool 324 cannot continue to move upward. The fluid can enter the sleeve 321 from below from the pressure relief inlet 322, sequentially flow through the opening 573 and the flow regulating groove 348, and then flow out from the pressure relief outlet 123, i.e. the pressure relief inlet 322 and the pressure relief outlet 123 are in fluid communication through the pressure relief passage 328. Under the action of the fluid pressure of the fluid, the spool 324 can be kept in the spool opening position.

[0062] When the pressure difference between the valve inlet 102 and the valve outlet 103 gradually increases, the pressure difference between the pressure relief outlet 123 and the pressure relief inlet 322 also gradually increases, and the spool 324 linearly moves to the spool closing position, i.e. moves downward, under the elastic force of the second damping element 344. Until the outer sealing surface 453 of the spool 324 abuts the inner sealing surface 452 of the sleeve 321 again, the spool 324 reaches the spool closing position as shown in FIG. 5A.

[0063] Thus, the second switching device 320 can be opened or closed based on the pressure difference between the valve inlet 102 and the valve outlet 103, so as to connect or disconnect the pressure relief passage 328.

[0064] In addition, when the second switching device 320 is in the open state, by rotating the engagement column 464, the rotating block 325 and the sleeve 321 can also be rotated, so that different sizes of openings on the flow regulating groove 348 are aligned with the pressure relief outlet 123, thereby adjusting the flow size in the pressure relief passage 328.

[0065] Figures 6A and 6B show cross-sectional views of the second switch device 320 along the line B-B in Figure 1C when the second switch device 320 is in the open state and the flow rate through the pressure relief passage 328 is at the minimum flow rate and the maximum flow rate, respectively. As shown in Figure 6A, the second switch device 320 is in the open state and the rotating tab 463 at the top of the rotating block 325 abuts the limiting pin 467 corresponding to the minimum flow rate. At this time, the leftmost end of the flow regulating groove 348 is aligned with the pressure relief outlet 123. When the fluid is discharged from the pressure relief outlet 123 through the pressure relief passage 328 from the pressure relief inlet 322, the narrowest part of the flow regulating groove 348 is in communication with the pressure relief outlet 123, so that the flow regulating groove 348 has the smallest flow area, and thus the fluid flowing out of the pressure relief outlet 123 has the minimum flow rate.

[0066] When the operator rotates the engaging column 464 to rotate the rotating block 325 and the sleeve 321 to the left, the width of the flow regulating groove 348 gradually increases, so that the flow area gradually increases, thereby gradually increasing the flow rate of the fluid flowing out of the pressure relief outlet 123, until reaching the position shown in Figure 6B.

[0067] As shown in Figure 6B, the second switch device 320 is still in the open state and the rotating tab 463 at the top of the rotating block 325 abuts the limiting pin 467 corresponding to the maximum flow rate. At this time, the rightmost end of the flow regulating groove 348 is aligned with the pressure relief outlet 123. When the fluid is discharged from the pressure relief outlet 123 through the pressure relief passage 328 from the pressure relief inlet 322, the widest part of the flow regulating groove 348 is in communication with the pressure relief outlet 123, so that the flow regulating groove 348 has the largest flow area, and thus the fluid flowing out of the pressure relief outlet 123 has the maximum flow rate.

[0068] Thus, by rotating the sleeve 321, the flow regulating groove 348 can be connected to the pressure relief outlet 123 with different flow areas, thereby adjusting the flow rate of the fluid flowing out of the pressure relief outlet 123, i.e., adjusting the flow rate of the fluid in the pressure relief passage 328.

[0069] Those skilled in the art can understand that the shape and size of the flow regulating groove can be set according to specific needs. According to the specific shape and size of the flow regulating groove, the position of the limiting pin can be set accordingly.

[0070] FIG. 7 shows a structural block diagram of a refrigeration system including the valve device 100 in FIG. 1A. As shown in FIG. 7, the refrigeration system 790 includes a compressor 793, a condenser 794, a throttling device 792, and an evaporator 791, which are connected through pipes into a closed system and are filled with refrigerant in the system. The refrigeration system 790 further includes the valve device 100 connected between the evaporator 791 and the compressor 793. The valve inlet 102 of the valve device 100 is in fluid communication with a gas outlet 795 of the evaporator 791, and the valve outlet 103 of the valve device 100 is in fluid communication with a suction end 796 of the compressor 793. In this embodiment, the compressor is taken as an example of a screw compressor.

[0071] The refrigerant flows through the compressor 793, the condenser 794, the throttling device 792, and the evaporator 791 in turn, so that the refrigeration system 790 can cool or heat externally. Specifically, the high-pressure gaseous refrigerant discharged from the discharge end 797 of the compressor 793 flows into the condenser 794, is condensed into high-pressure saturated liquid refrigerant by releasing heat in the condenser 794, is then discharged from the condenser 794 and flows into the throttling device 792, is throttled into low-pressure two-phase refrigerant and then flows into the evaporator 791, is evaporated into low-pressure gaseous refrigerant by absorbing heat in the evaporator 791, and finally flows out of the evaporator 791 through the gas outlet 795 and is sucked into the suction end 796 of the compressor 793 through the valve device 100, completing the circulation of the refrigerant.

[0072] When the refrigeration system 790 is running, the refrigerant pressure at the gas outlet 795 of the evaporator 791 (i.e., the refrigerant pressure at the valve inlet 102) is greater than the refrigerant pressure at the suction end 796 of the compressor 793 (i.e., the refrigerant pressure at the valve outlet 103), and the pressure difference is greater than the first threshold value, so that the first switching device 110 of the valve device 100 is opened, the second switching device 320 is closed, and the refrigerant can flow from the evaporator 791 into the compressor 793 through the main fluid passage 108 of the valve device 100.

[0073] When the refrigeration system 790 is stopped, the refrigerant pressure at the outlet 795 of the evaporator 791 decreases. When the compressor 793 is stopped, the screw stops rotating, and the suction end 796 of the compressor 793 is in communication with the high pressure cavity in the compressor 793, so that the refrigerant pressure at the suction end 796 increases. The first switching device 110 of the valve device 100 is closed, and the main fluid passage 108 of the valve device 100 is disconnected. When the refrigerant pressure at the outlet 795 of the evaporator 791 (i.e. the refrigerant pressure at the valve inlet 102) is less than the refrigerant pressure at the suction end 796 of the compressor 793 (i.e. the refrigerant pressure at the valve outlet 103), and the pressure difference is less than the second threshold value, the second switching device 320 of the valve device 100 is opened, and the fluid can flow from the compressor 793 to the evaporator 791 through the pressure relief passage 328 of the valve device 100 to balance the pressure difference of the fluid between the valve inlet 102 and the valve outlet 103. By rotating the engaging column 464 in the second switching device 320, the flow rate of the fluid through the pressure relief passage 328 can also be adjusted, so as to control the speed of balancing the pressure difference.

[0074] Thus, when the refrigeration system 790 is restarted, the pressure inside the compressor 793 will not be too high, and the compressor 793 will not be started with overload. Since the compressor 793 usually includes a fluid such as oil that cannot be miscible with the refrigerant, by controlling the speed of balancing the pressure difference by the valve device 100, both the liquid level fluctuation caused by too high speed and the delay in pressure relief can be avoided.

[0075] In the present application, the main fluid passage and the pressure relief passage are independently connected or disconnected in the valve device, so that the second switching device will not affect the structure and function of the first switching device. The valve device can not only limit the one-way flow of the fluid from the valve inlet to the valve outlet, but also can realize the pressure relief flow of the fluid from the valve outlet to the valve inlet to balance the pressure between the valve inlet and the valve outlet. Therefore, the valve device of the present application is not only simple in structure, but also is particularly suitable for application occasions with pressure fluctuation. Moreover, the second switching device is arranged inside the valve stem, so that no great changes need to be made to the external structure and connection relationship of the existing valve device.

[0076] The valve device of the present application can also adjust the flow rate of the fluid during the pressure relief by arranging the flow adjusting groove in the second switching device, so as to control the speed of pressure relief or balancing the pressure difference.

[0077] The valve device of the present application can adjust the size of the first threshold value and the second threshold value by arranging appropriate first damping elements and second damping elements, so that the first switching device and the second switching device are opened or closed within the expected pressure difference range.

[0078] While the application will be described with reference to the specific embodiments illustrated in the drawings, it should be understood that various changes can be made to the embodiments described and illustrated without departing from the spirit and scope of the application. One skilled in the art will also realize that the application can be practiced with a different set of steps, and / or in conjunction with other components not expressly listed or described herein. It is therefore intended that the disclosure not be limited to the illustrative embodiments.

Claims

1. A valve device, characterized by Comprising: a valve seat (101) having a valve inlet (102), a valve outlet (103), a main fluid passage (108) and a pressure relief passage (328) defined therein, each of the main fluid passage (108) and the pressure relief passage (328) independently communicating the valve inlet (102) and the valve outlet (103); a first switching device (110) disposed in the main fluid passage (108) and configured to be able to close to disconnect the main fluid passage (108) or open to connect the main fluid passage (108); and a second switching device (320) disposed in the pressure relief passage (328) and configured to be able to close to disconnect the pressure relief passage (328) or open to connect the pressure relief passage (328); wherein the first switching device (110) and the second switching device (320) are configured such that when the first switching device (110) is open, fluid is allowed to flow through the main fluid passage (108), and when the first switching device (110) is closed, the second switching device (320) is controllably open to allow fluid to flow through the pressure relief passage (328).

2. The valve device of claim 1, wherein: the first switching device (110) is configured to be unidirectionally open based on a pressure difference between the valve inlet (102) and the valve outlet (103) to allow the fluid to flow unidirectionally from the valve inlet (102) through the main fluid passage (108) to the valve outlet (103); the first switching device (110) is open when the pressure of the valve inlet (102) is greater than the pressure of the valve outlet (103) and the pressure difference between the two is greater than a first threshold, otherwise the first switching device (110) is closed.

3. The valve device of claim 1, wherein: the second switching device (320) is configured to be unidirectionally open based on a pressure difference between the valve inlet (102) and the valve outlet (103) to allow the fluid to flow unidirectionally from the valve outlet (103) through the pressure relief passage (328) to the valve inlet (102); the second switching device (320) is unidirectionally open when the pressure of the valve outlet (103) is greater than the pressure of the valve inlet (102) and the pressure difference between the two is greater than a second threshold, otherwise the second switching device (320) is closed.

4. The valve device of claim 3, wherein: the valve seat (101) includes a valve stem (109) defining the pressure relief passage (328) therein, the pressure relief passage (328) forming a pressure relief inlet (322) and a pressure relief outlet (123) on the valve stem (109); wherein the pressure relief inlet (322) is in fluid communication with the valve outlet (103), and the pressure relief outlet (123) is in fluid communication with the valve inlet (102); and wherein the second switching device (320) is configured to allow fluid to flow from the valve outlet (103) to the pressure relief inlet (322), through the pressure relief passage (328) to the pressure relief outlet (123), and out of the valve inlet (102) when the second switching device (320) is opened in one direction.

5. The valve device according to claim 4, wherein: the second switching device (320) comprises: a sleeve (321) having an inwardly protruding shoulder (451) with an inner sealing surface (452); and a spool (324) disposed in the sleeve (321) and configured to move linearly, the spool (324) having an outer sealing surface (453) configured to contact the inner sealing surface (452); wherein the pressure relief inlet (322) and the pressure relief outlet (123) are disposed on opposite sides of the shoulder (451) respectively, such that the outer sealing surface (453) of the spool (324) is configured to abut the inner sealing surface (452) of the shoulder (451) to disconnect the pressure relief passage (328) as the spool (324) moves linearly; and the outer sealing surface (453) of the spool (324) is configured to move away from the inner sealing surface (452) of the shoulder (451) to connect the pressure relief passage (328).

6. The valve device according to claim 5, wherein: the second switching device (320) further comprises a second damping element (344) connected between the spool (324) and the sleeve (321), the second damping element (344) being configured to apply a holding force to the spool (324) to keep the outer sealing surface (453) of the spool (324) abutting the inner sealing surface (452) of the shoulder (451) of the sleeve (321), the holding force being configured to correspond to a second threshold of a pressure difference between the valve outlet (103) and the valve inlet (102).

7. The valve device according to claim 5, wherein: the sleeve (321) is configured to rotate in the valve stem (109); the sleeve (321) has a flow regulating groove (348) extending through the sleeve (321) from the inside to the outside, the flow regulating groove (348) having different widths in a circumferential direction, such that the flow regulating groove (348) is configured to be in fluid communication with the pressure relief outlet (123) at different flow areas as the sleeve (321) rotates, thereby regulating the flow rate of fluid flowing out of the pressure relief outlet (123).

8. The valve device of claim 7, wherein: the second switch device (320) further comprises: a rotating block (325), wherein the rotating block (325) is cooperatively connected with the sleeve (321) to enable the rotating block (325) to rotate the sleeve (321); a seal (465); and a top cover (426) that is sealingly connected to the rotating block (325) by the seal (465) and is fixedly connected with the valve stem (109); wherein the rotating block (325) has a rotating knob (463), the top cover (426) is provided with at least one limiting pin (467) arranged to limit the rotating position of the rotating knob (463) to limit the rotating position of the sleeve (321).

9. The valve device of claim 3, wherein: the first switch device (110) comprises: a valve shaft (105) connected to the valve seat (101); at least one valve flap (111) pivoted to the valve shaft (105), the valve flap (111) having a valve flap closed position and a valve flap open position, and the valve flap (111) being rotatable about the valve shaft (105) between the valve flap closed position and the valve flap open position; and at least one first damping element (104) connected between the valve shaft (105) and the corresponding valve flap (111), and a blocking portion (217) provided on the inner wall of the valve seat (101), wherein the first damping element (104) and the blocking portion (217) together keep the valve flap (111) in the valve flap closed position; wherein, when the valve flap (111) is in the valve flap closed position, the valve flap (111) abuts against the blocking portion (217) of the valve seat (101) to disconnect the main fluid passage (108), and when the valve flap (111) is away from the blocking portion (217), the main fluid passage (108) is connected.

10. The valve device of claim 9, wherein: the first damping element (104) is arranged to apply a holding force to each valve flap (111) to keep the valve flap (111) in the valve flap closed position, wherein the holding force of the first damping element (104) is arranged to correspond to a first threshold value of the pressure difference between the valve inlet (102) and the valve outlet (103).

11. A refrigeration system characterized by comprising: a compressor (793), an evaporator (791), a throttling device (792), and a condenser (794) arranged in a refrigerant circuit; and Valve device (100) according to any one of claims 1-10, arranged between the evaporator (791) and the compressor (793), wherein a valve inlet (102) of the valve device (100) is in fluid communication with the evaporator (791) and a valve outlet (103) of the valve device (100) is in fluid communication with the compressor (793).

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