Low-resistance backflow preventer

Abstract

The utility model discloses a low-resistance backflow preventer which comprises a valve body, a check valve, a water escape valve and a connecting assembly. The valve body is of a hollow structure, the number of the check valves is two, the two check valves are arranged in the valve body, one check valve is located at a liquid inlet of the valve body, the other check valve is located at a liquid outlet of the valve body, and the liquid flowing directions of the two check valves are the same; a liquid drainage opening is formed in the side wall of the valve body, the liquid drainage opening is formed between the two check valves, the water drainage valve is located outside the valve body, and the water drainage valve is connected with the liquid drainage opening; the connecting assembly is arranged in the valve body and is hinged between the two check valves; the connecting assembly comprises a connecting rod and at least two connecting blocks, the two connecting blocks are installed on the opposite faces of the two check valves respectively, and the connecting rod is hinged between the two connecting blocks. According to the low-resistance backflow preventer, when opposite liquid impact force is applied to the two sides of the low-resistance backflow preventer, the leakage phenomenon does not occur, and the actual use requirement is met.

Description

Technical Field

[0001] The utility model relates to the technical field of pipeline valves, in particular to a low-resistance backflow preventer. Background Art

[0002] A backflow preventer is a device that strictly limits the flow of water in a pipe to one direction, effectively suppressing the backflow pollution of drinking water pipes and achieving the goal of preventing the water supply source from being polluted. There are two types of backflow preventers: double check backflow preventers and pressure reducing backflow preventers.

[0003] The double check backflow preventer is mainly composed of two check valves. There are two main types of traditional check valves: swing check valves and lift check valves. Both of these traditional check valves have various defects, especially the traditional check valves have huge resistance to water flow under low flow conditions. The swing check valve has less water flow resistance than the lift check valve, but the sealing surface of the check valve is easily worn during long-term opening and closing; while the mechanical mechanism of the traditional lift check valve effectively avoids the wear of the sealing surface, but this type of check valve has particularly severe resistance to water flow.

[0004] Unlike the double-check backflow preventer, the pressure-reducing backflow preventer is equipped with a drain valve in addition to two check valves, which makes it have lower resistance to water flow and also protects the upstream water source from being polluted. However, the two check valves of the traditional pressure-reducing backflow preventer are independent of each other and do not have any mechanical connection. When the valve flaps of the two independent check valves are simultaneously subjected to the impact force of the liquid in opposite directions, the pressure on one of the check valves increases the sealing force between its valve flap and the valve seat, and the valve flap and the valve seat are tightly closed, which increases the sealing and anti-leakage performance; the pressure on the valve flap of the other check valve overcomes the spring force of its corresponding torsion spring, so that the valve flap of the other check valve and the valve seat are in an open state, and the preventer leaks and cannot meet the use requirements. Utility Model Content

[0005] The purpose of the utility model is to provide a low-resistance backflow preventer, which does not leak when liquid impact forces are applied to both sides of the device in opposite directions, thereby meeting actual use requirements and overcoming the shortcomings of the prior art.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] A low-resistance backflow preventer comprises a valve body, a check valve, a drain valve and a connecting assembly; the valve body is a hollow structure, the check valve is provided with two structures, the two check valves are both arranged inside the valve body, one check valve is located at the liquid inlet of the valve body, the other check valve is located at the liquid outlet of the valve body, and the liquid flow directions of the two check valves are the same; a drain port is provided on the side wall of the valve body, and the drain port is arranged between the two check valves, the drain valve is located outside the valve body, and the drain valve is connected to the drain port; the connecting assembly is arranged inside the valve body, and the connecting assembly is hinged between the two check valves;

[0008] The connecting assembly comprises a connecting rod and at least two connecting blocks, the two connecting blocks are respectively installed on the opposite surfaces of the two check valves, and the connecting rod is hinged between the two connecting blocks.

[0009] Furthermore, the connecting rod includes a rod body, a first hinge seat and a second hinge seat, the first hinge seat and the second hinge seat are respectively detachably installed on both sides of the rod body, and the first hinge seat is hinged to one of the connecting blocks 32, and the second hinge seat is hinged to the other connecting block.

[0010] Further, the first hinge seat comprises a first U-shaped seat and a first latch, the first U-shaped seat is provided with a sliding groove, the first latch is rotatably installed inside the sliding groove, a sliding gap is left between the sliding groove and the first latch, the first latch can move along the extension direction of the sliding groove, and the connecting block is sleeved on the outside of the first latch and is hinged to the first hinge seat through the first latch;

[0011] The second articulated seat includes a second U-shaped seat and a second latch, the second U-shaped seat is provided with a mounting groove, and the second latch is rotatably mounted inside the mounting groove; the other connecting block is sleeved on the outside of the second latch, and the other connecting block is hinged to the second articulated seat through the second latch.

[0012] Furthermore, the connecting rod also includes at least two anti-loosening nuts, and the two anti-loosening nuts are symmetrically threadedly connected to the two sides of the rod body, and one anti-loosening nut abuts against the first U-shaped seat, and the other anti-loosening nut abuts against the second U-shaped seat.

[0013] Furthermore, the rod body is a positive and negative thread screw;

[0014] Both ends of the rod body are respectively provided with external threads with opposite rotation directions, the first U-shaped seat and the second U-shaped seat are both provided with internal threads, one end of the rod body is threadedly connected to the first U-shaped seat, and the other end of the rod body is threadedly connected to the second U-shaped seat.

[0015] Further, the check valve comprises a valve seat, a valve disc, a first pin shaft, a rocker, a torsion spring and a roller; the valve seat is mounted inside the valve body, one side of the valve disc is hinged to the upper end of the valve seat, and the other side of the valve disc is provided with the roller; the first pin shaft is rotatably mounted on the lower end of the valve seat, and the torsion spring is sleeved on the outside of the first pin shaft; the rocker comprises a mounting end and a movable end, the mounting end is sleeved on the outside of the first pin shaft and located at the middle of the torsion spring, and the rocker swings around the first pin shaft as an axis through the torsion spring; the roller abuts against the rocker, and the roller can move reciprocally between the mounting end and the movable end, and the valve disc can swing relative to the valve seat through the roller;

[0016] One of the connection blocks is installed on the inner side surface of the valve disc of one of the check valves, and the other of the connection blocks is installed on the inner side surface of the valve disc of the other of the check valves.

[0017] Furthermore, the check valve also includes at least two limit hooks, the two limit hooks are symmetrically arranged at the lower end of the valve seat, the first pin shaft is rotatably installed between the two limit hooks, and the first pin shaft is rotatably installed at the lower end of the valve seat through the two limit hooks, and the limit hooks are used to limit the torsion arm of the torsion spring.

[0018] Furthermore, the movable end of the rocker is provided with a return hook portion;

[0019] A limiting groove is arranged on the side of the valve flap, the roller is installed inside the limiting groove, and the limiting groove is used to accommodate the return hook portion.

[0020] Furthermore, at least two supports are provided at the upper end of the side surface of the valve seat, and the two supports are symmetrically installed on both sides of the valve seat;

[0021] The valve flap also includes a second pin shaft, which is rotatably mounted on the two supports, and the valve flap is hinged to the valve seat through the second pin shaft.

[0022] Furthermore, it also includes a plurality of support members, which are distributed at the upper end and the lower end of the valve seat, and the support members are located between the valve seats, and the valve seat is abutted against the valve body through the plurality of support members.

[0023] The technical solution provided by the embodiment of the present application may include the following beneficial effects: when liquid backflows, the two check valves are closed at the same time, and the liquid inside the hollow valve body flows away from the drain valve below, preventing the liquid from flowing back and ensuring the hygienic safety of the upstream liquid; at the same time, since the connecting component is arranged inside the valve body and the connecting component is hinged between the two check valves, the synchronous movement of the two check valves is ensured, that is, the two check valves are opened or closed at the same time and the opening and closing degrees are consistent. When any one of the check valves is closed, the other check valve is also closed, avoiding that when one of the check valves is in a closed state, the other check valve is in an open state, thereby ensuring that the device prevents leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The utility model is a structural schematic diagram of a low-resistance backflow preventer.

[0025] Figure 2 The utility model is a cross-sectional view of a check valve of a low-resistance backflow preventer in a closed state.

[0026] Figure 3 The utility model is a cross-sectional view of a check valve of a low-resistance backflow preventer in an open state.

[0027] Figure 4 The utility model is a partial structural schematic diagram of a low-resistance backflow preventer.

[0028] Figure 5 The utility model is a structural schematic diagram of a connecting component in a low-resistance backflow preventer.

[0029] Among them: valve body 1, check valve 2, valve seat 21, support 211, valve disc 22, limiting groove 221, second pin shaft 222, first pin shaft 23, rocker 24, return hook 241, torsion spring 25, roller 26, limiting hook 27, connecting assembly 3, connecting rod 31, rod body 311, first hinge seat 312, first U-shaped seat 3121, sliding groove 31211, first latch 3122, second hinge seat 313, second U-shaped seat 3131, second latch 3132, anti-loosening nut 314, connecting block 32, support member 4, valve cover 5. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein

[0031] The same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0032] The technical solution provides a low-resistance backflow preventer, comprising a valve body 1, a check valve 2, a drain valve and a connecting assembly 3; the valve body 1 is a hollow structure, and the check valve 2 is provided with two structures, both of which are arranged inside the valve body 1, and one of the check valves 2 is located at the liquid inlet of the valve body 1, and the other of the check valves 3 is located at the liquid outlet of the valve body 1, and the liquid flow directions of the two check valves 3 are the same; a drain port is provided on the side wall of the valve body 1, and the drain port is arranged between the two check valves 2, the drain valve is located outside the valve body 1, and the drain valve is connected to the drain port; the connecting assembly 3 is arranged inside the valve body 1, and the connecting assembly 3 is hinged between the two check valves 2;

[0033] The connecting assembly 3 includes a connecting rod 31 and at least two connecting blocks 32 . The two connecting blocks 32 are respectively installed on opposite surfaces of the two check valves 2 , and the connecting rod 31 is hinged between the two connecting blocks 32 .

[0034] In order to prevent the preventer from leaking when water is flushed on both sides of it at the same time, the technical solution proposes a low-resistance backflow preventer, such as Figures 1 to 5 As shown, it includes a valve body 1, a check valve 2, a drain valve and a connecting component 3, the valve body 1 is a hollow structure; the structure of the check valve 2 is provided with two, the two check valves 2 are both arranged inside the valve body 1, and one check valve 2 is located at the liquid inlet of the valve body 1, and the other check valve 3 is located at the liquid outlet of the valve body 1; the side wall of the valve body 1 is provided with a drain port, and the drain port is arranged between the two check valves 2, the drain valve is located outside the valve body 1, and the drain valve is connected to the drain port; the working principle of this technical solution is: the function of the check valve 2 is to limit the fluid to flow in only one direction, under the action of the fluid pressure flowing in one direction, the check valve 2 allows the liquid to flow only from the liquid inlet of the valve body 1 to the valve body 1; when the liquid flows back, the two check valves 2 are closed at the same time, and the liquid inside the hollow valve body 1 flows away from the drain valve below, preventing the liquid from flowing back and ensuring the sanitation and safety of the upstream liquid; at the same time, since the connecting component 3 is arranged inside the valve body 1 and the connecting component 3 is hinged between the two check valves 2, the synchronous movement of the two check valves 2 is ensured, that is, the two check valves 2 are opened or closed at the same time and the opening and closing degrees are consistent. When any one of the check valves 2 is closed, the other check valve 2 is also closed, avoiding that when one of the check valves 2 is in a closed state, the other check valve 2 is in an open state, thereby ensuring that the device prevents leakage.

[0035] Further description, the connecting rod 31 includes a rod body 311, a first hinge seat 312 and a second hinge seat 313, the first hinge seat 312 and the second hinge seat 313 are respectively detachably installed on both sides of the rod body 311, and the first hinge seat 312 is hinged to one of the connecting blocks 32, and the second hinge seat 313 is hinged to another of the connecting blocks 32.

[0036] In a preferred embodiment of the present technical solution, the connecting rod 31 includes a rod body 311, a first articulated seat 312 and a second articulated seat 313, one articulated seat 312 is articulated to a connecting block 32, and the second articulated seat 313 is articulated to another connecting block 32, so that the connecting component 3 moves with the opening degree of the check valve 2, thereby ensuring that the preventer does not leak.

[0037] Further, the first hinge seat 312 includes a first U-shaped seat 3121 and a first latch 3122. The first U-shaped seat 3121 is provided with a sliding groove 31211. The first latch 3122 is rotatably installed inside the sliding groove 31211. A sliding gap is left between the sliding groove 31211 and the first latch 3122. The first latch 3122 can move along the extension direction of the sliding groove 31211. The connecting block 32 is sleeved on the outside of the first latch 3122 and is hinged to the first hinge seat 312 through the first latch 3122.

[0038] The second articulated seat 313 includes a second U-shaped seat 3131 and a second pin 3132. The second U-shaped seat 3131 is provided with a mounting groove, and the second pin 3132 can be rotatably installed inside the mounting groove 3211; the other connecting block 32 is sleeved on the outside of the second pin 3132, and the other connecting block 32 is hinged to the second articulated seat 313 through the second pin 3132.

[0039] In a preferred embodiment of the present technical solution, the first hinge seat 312 includes a first U-shaped seat 3121 and a first latch 3122. The first U-shaped seat 3121 is provided with a sliding groove 31211. The first latch 3122 is rotatably installed inside the sliding groove 31211. A sliding gap is left between the sliding groove 31211 and the first latch 3122. The first latch 3122 can move along the extension direction of the sliding groove 31211, so that even if there are processing and installation errors in the connecting component 3, it can be smoothly installed, thereby improving the success rate of assembly. In addition, since there is a sliding gap between the sliding groove 31211 and the first latch 3122, the sliding groove 31211 can effectively buffer small movements. Therefore, when the opening degree of one check valve 2 changes slightly, it will not affect the opening degree of the other check valve 2, so that the two check valves 2 have a certain degree of independence, thereby improving the stability of the overall structure of the preventer.

[0040] Furthermore, the second articulated seat 313 includes a second U-shaped seat 3131 and a second pin 3132. The second U-shaped seat 3131 is provided with at least two mounting grooves. The second pin 3132 can be rotatably installed inside the two mounting grooves 3211. The other connecting block 32 is hinged to the second articulated seat 313 through the second pin 3132. The articulation method is simple.

[0041] Preferably, the number of the sliding groove 31211 and the number of the mounting grooves are both two, and the two sliding grooves 31211 are symmetrically distributed on both sides of the first U-shaped seat 3121 ; the two mounting grooves are symmetrically distributed on both sides of the second U-shaped seat 3131 .

[0042] In a preferred embodiment of the present technical solution, two sliding grooves 31211 and two installation grooves are provided to improve the installation firmness of the first latch 3122 and the second latch 3132 , thereby improving the installation stability of the connection block 32 .

[0043] Further description, the connecting rod 31 also includes at least two anti-loosening nuts 314, and the two anti-loosening nuts 314 are symmetrically threadedly connected to the two sides of the rod body 311, and one anti-loosening nut 314 abuts against the first U-shaped seat 3121, and the other anti-loosening nut 314 abuts against the second U-shaped seat 3131.

[0044] In a preferred embodiment of the present technical solution, at least two anti-loosening nuts 314 are provided to make the installation of the first U-shaped seat 3121 and the second U-shaped seat 3131 more stable, thereby preventing them from falling off during use and affecting their normal use.

[0045] Further explanation: the rod body 311 is a positive and negative thread screw;

[0046] Both ends of the rod body 311 are respectively provided with external threads with opposite rotation directions, the first U-shaped seat 3121 and the second U-shaped seat 3131 are both provided with internal threads, one end of the rod body 311 is threadedly connected to the first U-shaped seat 3121, and the other end of the rod body 311 is threadedly connected to the second U-shaped seat 3131.

[0047] In a preferred embodiment of the present technical solution, the rod body 311 is a positive and negative thread screw, and both ends of the positive and negative thread screw are respectively provided with external threads with opposite rotation directions. One end of the rod body 311 is threadedly connected to the first U-shaped seat 3121, and the other end of the rod body 311 is threadedly connected to the second U-shaped seat 3131, so that the positive and negative thread screw is threadedly connected to the first hinged seat 312 through the first U-shaped seat 3121, and the positive and negative thread screw is threadedly connected to the second hinged seat 313 through the second U-shaped seat 3131, so that during installation or disassembly, the positive and negative thread screw only needs to be rotated in one direction to simultaneously bring the first hinged seat 312 and the second hinged seat 313 together or apart, which is convenient for installation and maintenance.

[0048] Further description, the check valve 2 includes a valve seat 21, a valve disc 22, a first pin shaft 23, a rocker 24, a torsion spring 25 and a roller 26; the valve seat 21 is installed inside the valve body 1, one side of the valve disc 22 is hinged to the upper end of the valve seat 21, and the other side of the valve disc 22 is provided with the roller 26; the first pin shaft 23 is rotatably installed on the lower end of the valve seat 21, and the torsion spring 25 is sleeved on the outside of the first pin shaft 23; the rocker 24 includes a mounting end and a movable end, the mounting end is sleeved on the outside of the first pin shaft 23 and is located in the middle of the torsion spring 25, and the rocker 24 swings with the first pin shaft 23 as the axis through the torsion spring 25; the roller 26 abuts against the rocker 24, and the roller 26 can move reciprocatingly between the mounting end and the movable end, and the valve disc 22 can swing relative to the valve seat 21 through the roller 26;

[0049] One of the connection blocks 32 is installed on the inner side of the valve disc 22 of one of the check valves 2 , and the other of the connection blocks 32 is installed on the inner side of the valve disc 22 of the other of the check valves 2 .

[0050] In a preferred embodiment of the present technical solution, the check valve 2 includes a valve seat 21, a valve disc 22, a first pin shaft 23, a rocker 24, a torsion spring 25 and a roller 26; the valve seat 21 is installed inside the valve body 1, one side of the valve disc 22 is hinged to the upper end of the valve seat 21, and the other side of the valve disc 22 is provided with a roller 26; the first pin shaft 23 is rotatably installed on the lower end of the valve seat 21, and the torsion spring 25 is sleeved on the outside of the first pin shaft 23; the rocker 24 includes a mounting end and a movable end, the mounting end is sleeved on the outside of the first pin shaft 23 and is located in the middle of the torsion spring 25, and the rocker 24 swings with the first pin shaft 23 as the axis through the torsion spring 25; the roller 26 abuts against the rocker 24, and the roller 26 can move reciprocatingly between the mounting end and the movable end, and the valve disc 22 can swing relative to the valve seat 21 through the roller 26; when the valve disc 22 is in a closed state, the torsion spring 25 The spring force of 25 acts on the rocker 24, so that the roller 26 is pressed against the rocker 24, ensuring that when the valve flap 22 is in a closed state, there is sufficient sealing force between the valve seat 21 and the valve flap 22; when the liquid flow rate increases, the liquid impact force on the valve flap 22 overcomes the spring force of the torsion spring 25, and the opening degree of the valve flap 22 increases, so that the roller 26 moves from the installation end of the rocker 24 to the movable end of the rocker 24, and the contact point between the rocker 24 and the roller 26 changes continuously as the opening degree of the valve flap 22 increases. The force arm of the rocker 24 on the valve flap 22 continues to increase, so that during the opening process of the valve flap 22, the resistance of the valve flap 22 to the liquid continues to decrease; in addition, no matter whether the liquid flow rate increases or decreases, the roller 26 rolls along the length direction of the rocker 24, and the rocker 24 plays a certain guiding role, making the opening of the valve flap 22 more stable.

[0051] Preferably, a valve cover 5 is further included, and the valve cover 5 is detachably mounted on the top of the valve body 1 .

[0052] In a preferred embodiment of the present technical solution, a removable valve cover 5 is provided so that when installing the check valve 2, one check valve 2 is first inserted into the valve body 1 at the liquid outlet, and then the other check valve 2 is inserted into the valve body 1 at the liquid inlet, and then the two check valves 2 are fixedly installed in the valve body 1 using the support member 4, thereby ensuring that the check valve 2 is in close contact with the components under frequent vibration conditions and will not loosen, thereby improving the convenience of installation.

[0053] Further description, the check valve 2 also includes at least two limit hooks 27, the two limit hooks 27 are symmetrically arranged at the lower end of the valve seat 21, the first pin shaft 23 is rotatably installed between the two limit hooks 27, and the first pin shaft 23 is rotatably installed at the lower end of the valve seat 21 through the two limit hooks 27, and the limit hooks 27 are used to limit the torsion arm of the torsion spring 25.

[0054] In a preferred embodiment of the present technical solution, by setting two limit hooks 27, it is only necessary to insert the torsion spring 25 onto the first pin shaft 23, and then use a screwdriver to pry the torsion arm of the torsion spring 25 onto the corresponding limit hook 27, thereby simplifying the installation and disassembly of the torsion spring 25.

[0055] Further explanation, the movable end of the rocker 24 is provided with a return hook portion 241;

[0056] A limiting groove 221 is disposed on the side of the valve flap 22 . The roller 26 is installed inside the limiting groove 221 . The limiting groove 221 is used to accommodate the return hook portion 241 .

[0057] In a preferred embodiment of the present technical solution, a return hook portion 241 is provided at the movable end of the rocker 24. When the opening degree of the valve flap 22 reaches the limit position, the return hook portion 241 is used to clamp the roller 26, so that the valve flap 22 cannot be opened further, thereby playing a limiting role.

[0058] Furthermore, a limiting groove 221 is provided on the side of the valve flap 22, and the roller 26 is installed inside the limiting groove 221. The limiting groove 221 is used to accommodate the return hook portion 241, thereby limiting the movement of the return hook portion 241, so that the opening degree of the valve flap 22 reaches the limit position, and the valve flap 22 cannot be further opened, thereby further strengthening the limiting effect.

[0059] Further, at least two supports 211 are provided on the upper end of the side surface of the valve seat 21, and the two supports 211 are symmetrically installed on both sides of the valve seat 21;

[0060] The valve flap 22 further includes a second pin shaft 222 , which is rotatably mounted on the two supports 211 , and the valve flap 22 is hinged to the valve seat 21 via the second pin shaft 222 .

[0061] In a preferred embodiment of the present technical solution, the valve flap 22 is hinged to the valve seat 21 by providing a support 211 and a second pin shaft 222, and the hinged manner is simple.

[0062] Further description, it also includes a plurality of support members 4, which are distributed at the upper end and the lower end of the valve seat 21, and the support members 4 are located between the valve seats 21, and the valve seat 21 is abutted against the valve body 1 through the plurality of support members 4.

[0063] In a preferred embodiment of the present technical solution, a plurality of support members 4 are provided, and the support members 4 are used to make the valve seat 21 abut against the valve body 1, so that the check valve 2 is installed inside the valve body 1. The installation method is simple and the stability of the installation is improved.

[0064] Preferably, the number of the supporting members 4 is four.

[0065] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0066] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps described in these embodiments do not limit the scope of the utility model. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0067] In the description of the present utility model, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present utility model; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0068] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0069] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the utility model.

[0070] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0071] The technical principle of the present invention is described above in combination with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the protection scope of the present invention in any way. Based on the explanations here, technicians in this field can think of other specific implementation methods of the present invention without creative work, and these methods will fall within the protection scope of the present invention.

Claims

1. A low resistance backflow preventer, characterized in that: It comprises a valve body, a check valve, a drain valve and a connecting assembly; the valve body is a hollow structure, the check valve is provided with two structures, the two check valves are both arranged inside the valve body, one check valve is located at the liquid inlet of the valve body, the other check valve is located at the liquid outlet of the valve body, and the liquid flow directions of the two check valves are the same; a drain port is provided on the side wall of the valve body, and the drain port is arranged between the two check valves, the drain valve is located outside the valve body, and the drain valve is connected to the drain port; the connecting assembly is arranged inside the valve body, and the connecting assembly is hinged between the two check valves; The connecting assembly comprises a connecting rod and at least two connecting blocks, the two connecting blocks are respectively installed on the opposite surfaces of the two check valves, and the connecting rod is hinged between the two connecting blocks.

2. A low resistance backflow preventer according to claim 1, characterized in that: The connecting rod includes a rod body, a first hinge seat and a second hinge seat, the first hinge seat and the second hinge seat are respectively detachably installed on both sides of the rod body, and the first hinge seat is hinged to one of the connecting blocks 32, and the second hinge seat is hinged to the other connecting block.

3. A low resistance backflow preventer according to claim 2, characterized in that: The first hinge seat comprises a first U-shaped seat and a first latch, the first U-shaped seat is provided with a sliding groove, the first latch is rotatably installed inside the sliding groove, a sliding gap is left between the sliding groove and the first latch, the first latch can move along the extension direction of the sliding groove, and the connecting block is sleeved on the outside of the first latch and is hinged to the first hinge seat through the first latch; The second articulated seat includes a second U-shaped seat and a second latch, the second U-shaped seat is provided with a mounting groove, and the second latch is rotatably mounted inside the mounting groove; the other connecting block is sleeved on the outside of the second latch, and the other connecting block is hinged to the second articulated seat through the second latch.

4. A low resistance backflow preventer according to claim 3, characterized in that: The connecting rod also includes at least two anti-loosening nuts, which are symmetrically threadedly connected to the two sides of the rod body, and one anti-loosening nut abuts against the first U-shaped seat, and the other anti-loosening nut abuts against the second U-shaped seat.

5. A low resistance backflow preventer according to claim 3, characterized in that: The rod body is a positive and negative thread screw; Both ends of the rod body are respectively provided with external threads with opposite rotation directions, the first U-shaped seat and the second U-shaped seat are both provided with internal threads, one end of the rod body is threadedly connected to the first U-shaped seat, and the other end of the rod body is threadedly connected to the second U-shaped seat.

6. A low resistance backflow preventer according to claim 1, characterized in that: The check valve comprises a valve seat, a valve disc, a first pin shaft, a rocker, a torsion spring and a roller; the valve seat is mounted inside the valve body, one side of the valve disc is hinged to the upper end of the valve seat, and the other side of the valve disc is provided with the roller; the first pin shaft is rotatably mounted on the lower end of the valve seat, and the torsion spring is sleeved on the outside of the first pin shaft; the rocker comprises a mounting end and a movable end, the mounting end is sleeved on the outside of the first pin shaft and located at the middle of the torsion spring, and the rocker swings around the first pin shaft as an axis through the torsion spring; the roller abuts against the rocker, and the roller can move reciprocally between the mounting end and the movable end, and the valve disc can swing relative to the valve seat through the roller; One of the connection blocks is installed on the inner side surface of the valve disc of one of the check valves, and the other of the connection blocks is installed on the inner side surface of the valve disc of the other of the check valves.

7. A low resistance backflow preventer according to claim 6, characterized in that: The check valve also includes at least two limit hooks, the two limit hooks are symmetrically arranged at the lower end of the valve seat, the first pin shaft is rotatably installed between the two limit hooks, the first pin shaft is rotatably installed at the lower end of the valve seat through the two limit hooks, and the limit hooks are used to limit the torsion arm of the torsion spring.

8. A low resistance backflow preventer according to claim 6, characterized in that: The movable end of the rocker is provided with a return hook portion; A limiting groove is arranged on the side of the valve flap, the roller is installed inside the limiting groove, and the limiting groove is used to accommodate the return hook portion.

9. A low resistance backflow preventer according to claim 6, characterized in that: At least two supports are provided at the upper end of the side surface of the valve seat, and the two supports are symmetrically installed on both sides of the valve seat; The valve flap also includes a second pin shaft, which is rotatably mounted on the two supports, and the valve flap is hinged to the valve seat through the second pin shaft.

10. A low resistance backflow preventer according to claim 6, characterized in that: It also includes a plurality of support members, which are distributed at the upper end and the lower end of the valve seat and are located between the valve seats. The valve seat is in contact with the valve body through the plurality of support members.

Images