Backstop Negative Pressure Flow Relief Valve

Abstract

The present invention discloses a backstop negative pressure flow relief valve with a limit. It includes a valve seat body having a suction hole and a relief hole, and a valve core that can be installed in the valve seat body. The head of the valve core is set as a conical head. After the valve core is screwed into the valve seat body, the conical head can cooperate with and seal the suction hole. A ring groove is also provided in the valve seat body on the same axis as the suction hole. A clamping groove is provided on the valve core, and a circlip is placed in the clamping groove. The circlip can enter from the rear end face of the valve seat body and be limited in the ring groove, and form a certain amount of eccentricity with the ring groove to limit the valve core from withdrawing from the valve seat body. Its advantages are: its structural design is very ingenious, the installation, operation and use are all simple and convenient, without adding extra assembly processes, greatly improving the production and use efficiency, and making its use reliability very good by utilizing the unique characteristics of the circlip.

Description

Technical Field

[0001] The present invention relates to a negative pressure flow relief valve structure, and more particularly to a non-return negative pressure flow relief valve with a limit. Background Art

[0002] In negative pressure medical devices such as sputum aspirators and suction devices, a flow relief valve is used. Its function is to divert the flow generated by the negative pressure pump and reduce the pressure. When the relief valve is closed, the pressure in the working air path is equal to the ultimate negative pressure generated by the negative pressure pump. When the relief valve is opened, according to the opening size of the relief valve, the working negative pressure value required by the user is achieved.

[0003] The existing flow relief valves generally consist of two parts: a valve seat and a valve core. The head of the valve core has a cone, which is connected to the valve seat by a thread. There is an air intake hole at the bottom of the valve seat and a through relief hole on the middle side. When the valve core is rotated clockwise, the cone at its head blocks the air intake hole at the bottom of the valve seat, and no flow is discharged. When the valve core is rotated counterclockwise, a gap is generated between the cone at the head of the valve core and the air intake hole at the bottom of the valve seat. At this time, the gas flows out from the through relief hole on the middle side of the valve seat. At this time, the pressure in the system pipeline decreases as the gap between the cone at the head of the valve core and the air intake hole at the bottom of the valve seat gradually increases, until the relief valve is fully opened and all the gas is discharged from the relief hole. At this time, the negative pressure value in the system pipeline returns to zero.

[0004] The problems existing in the design of this traditional flow relief valve are as follows: After the flow relief valve is fully opened by rotating the knob on the valve core assembly and the negative pressure value in the system pipeline has returned to zero, if the knob on the valve core assembly is further rotated, the entire valve core assembly may rotate, resulting in the valve core assembly becoming loose, falling off, or being pulled out. In addition, in the prior art, there are also some anti-rotation structures using anti-rotation nuts to avoid the problem of falling off, but their structural design is complex, the operation is troublesome, the use efficiency is low, the reliability is poor, and the manufacturing cost is also high. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a non-return negative pressure flow relief valve with a clever structural design, simple and convenient operation, which can prevent the valve core from being rotated out counterclockwise and ensure the reliability of use.

[0006] To solve the above technical problems, the non-return negative pressure flow relief valve of the present invention includes a valve seat body having an air intake hole and a relief hole, and a valve core that can be installed in the valve seat body. The head of the valve core is provided as a conical head. After the valve core is installed in the valve seat body, the conical head can cooperate with the air intake hole. A ring groove is also provided in the valve seat body on the same axis as the air intake hole. A clamping groove is provided on the valve core, and a circlip is placed in the clamping groove. The circlip can enter from the rear end face of the valve seat body and be limited in the ring groove to limit the valve core from withdrawing from the valve seat body.

[0007] A knob is fixedly installed at the tail of the valve core, and a damping spring is sleeved on the valve core and located between the knob and the valve seat body.

[0008] An external thread section is arranged on the valve core and located at the rear side of the conical head, and an internal thread section matching with the external thread section is arranged in the valve seat body.

[0009] A conical surface section is further arranged on the valve core at the root of the external thread section, and the clamping groove is arranged at the rear side root of the conical surface section.

[0010] The inner diameter of the open circlip is larger than the outer diameter of the external thread section of the valve core and smaller than the maximum diameter end of the conical surface section of the valve core.

[0011] A conical opening is arranged at the rear end face of the valve seat body.

[0012] The outer diameter of the clamping groove on the valve core is smaller than the inner diameter of the open circlip.

[0013] The open circlip is sleeved in the clamping groove and has an eccentric gap of 0.3 - 0.5 mm with the clamping groove in the radial direction.

[0014] The advantages of the present invention are as follows:

[0015] Due to the annular groove arranged in the valve seat body and on the same axis as the suction hole, and the clamping groove arranged on the valve core and provided with an open circlip, the eccentric characteristic of the open circlip and its unique structure are skillfully utilized for cooperation, so that the open circlip is in an eccentric state with the axis of the valve core body as soon as it falls into the clamping groove. At this time, when the valve core is reversed, the open circlip in the eccentric state is in limit cooperation with the valve seat body, avoiding accidental rotation of the valve core and detachment from the valve seat body during rotation. Its structural design is very ingenious, the installation, operation and use are all simple and convenient, without adding additional assembly processes, greatly improving the production and use efficiency, and making its use reliability very good by utilizing the unique characteristics of the circlip. Description of the Drawings

[0016] Figure 1 It is the front view structural schematic diagram of the anti - reverse negative - pressure flow pressure - relief valve of the present invention;

[0017] Figure 2 It is the sectional view schematic diagram of the anti - reverse negative - pressure flow pressure - relief valve of the present invention.

[0018] Figure 3 It is the exploded view schematic diagram of the anti - reverse negative - pressure flow pressure - relief valve of the present invention.

[0019] In the figure, 1 - suction hole; 2 - pressure - relief hole; 3 - valve seat body; 4 - valve core; 5 - conical head; 6 - annular groove; 7 - clamping groove; 8 - open circlip; 9 - knob; 10 - damping spring; 11 - external thread section; 12 - internal thread section; 13 - conical surface section; 14 - conical opening; 15 - opening. Detailed implementation mode

[0020] The anti-backflow negative pressure flow relief valve of the present invention will be further described in detail below in conjunction with the drawings and descriptions.

[0021] As shown in the figure, the anti-backflow negative pressure flow relief valve of the present invention includes a valve seat body 3 having a suction hole 1 and a pressure relief hole 2, and a valve core 4 that can be installed in the valve seat body. As can be seen from the figure, the head of the valve core 4 is provided as a conical head 5. An external thread section 11 is provided on the valve core 4 at the rear of the conical head. A conical surface section 13 is also provided on the valve core 4 at the root of the external thread section. The rear end of the conical surface section 13 of the valve core 4 is the rear main body section of the valve core. A clamping groove 7 is provided at the rear root of the conical surface section, that is, a clamping groove is opened at the intersection of the conical surface section and the rear main body section of the valve core 4. An open circlip 8 is placed in the clamping groove 7. The suction hole 1 is provided at the front end of the valve seat body 3. The valve seat body 3 has a through hole that penetrates from front to back. The pressure relief hole 2 is opened on the side wall at the front end of the valve seat body 3 and is located behind the suction hole 1, and is cross-connected to the through hole at the same time. The suction hole 1 is coaxially arranged in the through hole. An internal thread section 12 that cooperates with the external thread section 11 of the valve core is provided in the valve seat body 3. Of course, an external thread of the valve seat is also provided on the outer surface of the valve seat body for fixing the entire relief valve. A ring groove 6 that is located behind the internal thread section 12 and is on the same axis as the suction hole is also provided in the valve seat body 3, that is, a ring groove is provided at the rear end of the valve seat body, which can also be called a cavity. A plastic knob 9 for operating the valve core is fixedly installed at the tail of the valve core 4. By rotating the plastic knob 9, the valve core 4 is screwed into the valve seat body through the fine external thread of the external thread section and the fine internal thread of the internal thread section of the valve seat body, and finally the conical head is matched with the suction hole for sealing. At the same time, the open circlip 8 enters from the rear end face of the valve seat body and is limited in the ring groove, and forms an eccentricity of 0.3-0.5 mm with the outer diameter of the clamping groove, so that the open circlip can only enter but not exit, to prevent the valve core from withdrawing from the valve seat body. In addition, a damping spring 10 is sleeved on the valve core 4 between the knob and the valve seat body.

[0022] Further, the inner diameter of the snap ring 8 is larger than the outer diameter of the external thread section of the valve core and smaller than the maximum diameter end of the conical surface section of the valve core. That is to say, the inner diameter of the snap ring is slightly larger than the major diameter of the fine thread external thread of the valve core. The snap ring can be directly sleeved outside the fine thread external thread of the valve core until it touches the conical surface section 13 of the valve core and cannot be pushed any further. At the rear end face of the valve seat body 1, there is a conical opening 14 (chamfer). The outer diameter of the card slot on the valve core 4 is smaller than the inner diameter of the snap ring 8. The included angle of the conical surface section of the valve core is smaller than the angle of the conical opening 14 of the valve seat body. At the rear end face of the valve seat body 1, there is also an opening 15 located inside the conical opening 14. The diameter of this opening 15 is smaller than the inner diameter of the annular groove 6 of the valve seat body; the inner diameter of the annular groove 6 is larger than the outer diameter of the snap ring 8. Rotate the knob, and the fine thread external thread of the valve core is connected to the fine thread internal thread on the valve seat body until the snap ring touches the rear end face of the valve seat body. Then apply a little more torque. At this time, because the included angle of the conical surface section of the valve core is much smaller than the angle of the conical opening 14 of the valve seat body, the snap ring opens outward and slides into the card slot on the valve core. Continue to rotate the knob. Under the extrusion of the conical opening 14 (chamfer) of the valve seat body, the snap ring closes inward, and the outer diameter of the snap ring becomes smaller until it is just ≤ the inner diameter size of the opening 15 on the valve seat body. Then the snap ring is squeezed into the annular groove 6 of the valve seat body. When a slight clicking sound is heard, the snap ring falls into the annular groove on the valve seat body. The clicking sound is the sound of the snap ring restoring its elasticity and opening. In addition, because the outer diameter of the card slot 7 on the valve core is slightly smaller than the inner diameter of the snap ring, as soon as the snap ring falls into the card slot 7, it is in an eccentric state with respect to the axis of the valve core. At this time, if the valve core is reversed, the snap ring in the eccentric state is limited inside the valve seat body and cannot come out, and the valve core cannot be reversed either. In addition, it should be noted that: the outer diameter of the card slot (snap ring slot) 7 determines the size of the eccentricity of the snap ring; the aperture of the conical opening (snap ring retaining edge) 15 determines the ease of assembly. These two dimensions are the key dimensions for achieving feasibility and preventing the valve core from retreating.

[0023] The specific principle is as follows:

[0024] (1) Connect the square nut to the external thread of the valve seat body through its internal thread, mainly used to fix the assembled pressure relief valve on the operation panel of the machine;

[0025] (2) Before assembling the pressure relief valve, the plastic knob 9 has been connected to the valve core 4 through overmolding. The plastic knob has an anti-rotation groove, so reliable installation can be achieved. The function of the anti-rotation groove of the plastic knob is to ensure that the valve core must rotate with the plastic knob when the plastic knob rotates;

[0026] (3) The circlip is a standard part with a natural integer inner diameter. The circlip 8 is sleeved onto the conical head end of the valve core 4 until it touches the conical surface section (circlip guiding conical surface) of the valve core and cannot be pushed any further. The function of the circlip guiding conical surface is to ensure that the circlip is always concentric with the valve core during the entire assembly process.

[0027] (4) The damping spring is sleeved onto the conical head (air sealing conical head end) 5 of the valve core until it moves to the plastic knob.

[0028] (5) The air sealing conical head end on the valve core 4 is inserted into the through hole of the valve seat, and the external thread on the valve core 4 is connected to the internal thread of the valve seat body.

[0029] (6) Rotate the plastic knob until the circlip touches the edge end face of the circlip piece on the valve seat body, that is, the rear end face of the valve seat body, and then apply a little more torque. At this time, since the angle of the conical surface section (circlip guiding conical surface) on the valve core 4 is much smaller than the chamfer angle of the edge end face of the circlip piece on the valve seat body, the opening of the circlip increases outward and slides into the annular groove (circlip groove) on the valve core.

[0030] (7) Continue to rotate the plastic knob. Under the extrusion of the chamfer of the edge end face of the circlip piece on the valve seat body, the opening of the circlip closes inward, and the outer diameter of the circlip becomes smaller until it is just equal to or less than the opening diameter size of the edge end face of the circlip piece on the valve seat body. The circlip starts to enter the valve seat body until a slight clicking sound is heard, and the circlip falls into the annular groove (inner circlip piece inner cavity) on the valve seat body. The clicking sound is the sound of the circlip piece restoring its elasticity and opening.

[0031] (8) Since the outer diameter of the circlip groove on the valve core is slightly smaller than the inner diameter of the circlip, once the circlip piece falls into the card slot, it is in an eccentric state with respect to the axis of the valve core. At this time, if the valve core is reversed, the eccentric circlip blocks the inside of the valve seat body and cannot come out, and the valve core cannot be rotated in reverse either.

[0032] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples either. Changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A non-return negative pressure flow relief valve, comprising a valve seat body (3) having a suction hole (1) and a relief hole (2), and a valve core (4) that can be installed in the valve seat body, characterized in that: The head of the valve core (4) is provided as a conical head (5). After the valve core (4) is installed in the valve seat body, the conical head can cooperate with the suction hole. A ring groove (6) coaxial with the suction hole is further provided in the valve seat body (3). A clamping groove (7) is provided on the valve core (4), and a circlip (8) is arranged in the clamping groove (7). The circlip (8) can enter from the rear end face of the valve seat body and be limited in the ring groove to prevent the valve core from withdrawing from the valve seat body. An external thread section (11) is provided on the valve core (4) at the rear side of the conical head. A conical surface section (13) is further provided on the valve core (4) at the root of the external thread section. The clamping groove (7) is arranged at the rear side root of the conical surface section. The inner diameter of the circlip (8) is larger than the outer diameter of the external thread section of the valve core and smaller than the maximum diameter end of the conical surface section of the valve core. The outer diameter of the clamping groove on the valve core (4) is smaller than the inner diameter of the circlip (8). The circlip (8) is sleeved in the clamping groove (7) and has an eccentric gap with the clamping groove in the radial direction. A conical opening (14) is provided at the rear end face of the valve seat body (3). The outer diameter of the clamping groove on the valve core (4) is smaller than the inner diameter of the circlip (8). The angle of the conical surface section of the valve core is smaller than the angle of the conical opening (14) of the valve seat body. An opening (15) is further provided at the rear end face of the valve seat body (3) inside the conical opening (14). The diameter of the opening (15) is smaller than the inner diameter of the ring groove (6) of the valve seat body. The circlip (8) is sleeved in the clamping groove (7) and has an eccentric gap of 0.3 - 0.5 mm with the clamping groove in the radial direction.

2. The anti-backflow negative pressure flow pressure relief valve according to claim 1, characterized in that: A knob (9) is fixedly installed at the tail of the valve core (4). A damping spring (10) is sleeved on the valve core (4) between the knob and the valve seat body.

3. The backflow prevention negative pressure flow relief valve according to claim 1 or 2, characterized in that: An internal thread section (12) matching the external thread section is provided in the valve seat body (3).

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