A square check valve for a ventilator outlet vertical pipeline

Abstract

The utility model belongs to check valve technical field, concretely is a square check valve for ventilator outlet vertical pipeline, including the shell of square structure, the left valve plate and right valve plate are rotationally assembled in the shell inside, one root of pivot is in common through the left valve plate and right valve plate, the pivot is all eccentric distribution on the left valve plate, right valve plate, and the distance of the pivot to right valve plate end is less than the sum of left valve plate and right valve plate length 1 / 2, the side of left valve plate closing direction and the side of right valve plate closing direction all are provided with limit stop, the limit stop is the limit boss perpendicular with valve plate closing direction, the limit stop is installed in the shell inside through bolt, compared with prior art, the utility model simple structure, rely on the weight closure no trouble point, sealing effect is reliable, and the pressure loss is small, and the noise is small.

Description

Technical Field

[0001] This utility model relates to the field of check valve technology, and in particular to a square check valve for use in the vertical pipeline of a ventilation fan outlet. Background Technology

[0002] Ventilation fans are machines that rely on input mechanical energy to increase gas pressure and discharge gas. They are widely used in factories, mines, tunnels, cooling towers, boilers, and industrial kilns for ventilation and induced draft. With a wide range of applications, they are a commonly used general-purpose piece of equipment. Generally speaking, compared to Roots blowers, multi-stage centrifugal blowers, and compressors, centrifugal fans are suitable for operating conditions with pressures below 20 kPa and large flow rates. In practical designs, considering system stability, continuity, and safety, a one-for-one standby structure is typically used. Therefore, backflow prevention devices must be installed at the outlets of both fans. This device allows the medium to flow in one direction; when the medium flows backward, the valve automatically closes to prevent reverse flow. Installing outlet check valves serves the following purposes: preventing equipment damage, maintaining stable system pressure, avoiding medium mixing and contamination, and protecting downstream equipment.

[0003] Common types of outlet check valves include swing check valves, lift check valves, and disc check valves. They can be operated manually, electrically, or automatically. Swing check valves are circular in shape and are generally suitable for horizontal pipelines. They close by their own weight or spring force, but opening them reduces the flow area, increasing system resistance and affecting normal system operation. Lift check valves and disc check valves cannot achieve rapid closure. In terms of operation, manual operation cannot achieve rapid closure and poses personal safety hazards; while electric operation using an actuator can achieve rapid closure, it increases equipment costs and maintenance expenses. Therefore, to solve these problems, there is a need for a check valve that can achieve rapid closure, is low in cost, requires minimal maintenance, and has low pressure loss. Utility Model Content

[0004] This invention addresses the shortcomings of existing technologies by developing a square check valve for the vertical outlet pipe of a ventilation fan. This device is used at the air outlet of a ventilation fan, particularly in parallel systems consisting of two identical fans. In this system, one fan is on standby while the other is running. When the main fan starts, the standby fan outlet is sealed by this device to prevent gas backflow. When the main fan stops operating, the check valve at the main fan outlet automatically closes, while the check valve at the standby fan outlet automatically opens due to airflow, achieving uninterrupted system operation. The device has a simple structure, closes by its own weight with no fault points, provides reliable sealing, has low pressure loss, and low noise.

[0005] The technical solution of this utility model to solve the technical problem is as follows: a square check valve for a vertical pipe at the outlet of a ventilation fan, comprising a square outer shell, a left valve plate and a right valve plate rotatably assembled inside the outer shell, and a rotating shaft passing through the left and right valve plates. The rotating shaft is distributed off-center on both the left and right valve plates, and the distance from the rotating shaft to the end of the right valve plate is less than 1 / 2 of the sum of the lengths of the left and right valve plates. Limiting members are provided on both sides of the left valve plate in the closing direction and on both sides of the right valve plate in the closing direction. The limiting members are limiting bosses perpendicular to the closing direction of the valve plates, and the limiting members are installed inside the outer shell by bolts.

[0006] Preferably, the rotating shaft is provided with an oil injection nozzle, which is connected to the fitting clearance between the rotating shaft and the housing.

[0007] Preferably, a limit block is installed inside the housing on the side of the left valve plate in the opening direction.

[0008] Preferably, the limiting block is provided with a limiting block shock-absorbing pad.

[0009] Preferably, valve plate sealing gaskets are provided on both the left valve plate side near the closing direction and the right valve plate side near the closing direction.

[0010] Preferably, a limiting member sealing gasket is provided inside the housing of the limiting member, and the valve plate sealing gasket contacts the limiting member sealing gasket when the left valve plate and the right valve plate are closed.

[0011] Preferably, the inner wall of the outer casing has a shaft hole corresponding to the assembly position of the rotating shaft, the rotating shaft passes through the shaft hole, and both ends of the rotating shaft are connected to a rotating bearing, which is connected to the outer casing through a flange.

[0012] The effects provided in the utility model description are merely those of the embodiments, and not all the effects of the utility model. The above technical solution has the following advantages or beneficial effects: 1. This utility model achieves unbalanced force on the valve plate by setting the rotating shaft on one side of the off-center, making it easier to open. If it is set on the inner wall of the housing, opening the valve plate requires airflow to overcome the weight of the entire valve plate. At the same time, since the included angle is less than 90 degrees after opening, the air inlet area is larger than the air outlet area, resulting in a smaller outlet area, increased flow velocity, and greater pressure loss. 2. In this utility model, sealing gaskets are provided at the left and right valve plates and the limiting component, resulting in a better sealing effect; 3. An oil injection nozzle is added to the shaft head of this utility model, which allows for the timely addition of grease, making the shaft more flexible; 4. The entire device requires no manual labor or electric actuators, truly achieving a simple structure, few potential failure points, and reliable sealing; 5. Adding a damping pad to the limit block reduces the collision sound when the valve plate opens, thus reducing noise. Attached Figure Description

[0013] Figure 1 This is the front view of the present invention; Figure 2 for Figure 1 A cross-sectional view along the AA direction; Figure 3 for Figure 2 A magnified view of a portion of region A in the middle; Figure 4 for Figure 2 A magnified view of a portion of region B in the middle; Figure 5 This is a cross-sectional view of the shaft mounting section.

[0014] The components are: 1. Outer shell; 2. Limiting block; 21. Limiting block shock absorber; 3. Left valve plate; 4. Right valve plate; 5. Valve plate sealing gasket; 6. Limiting component; 61. Limiting component sealing gasket; 7. Rotating shaft; 71. Oil injection nozzle. Detailed Implementation

[0015] To clearly illustrate the technical features of this solution, the present invention will be described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0016] Example 1 See Figures 1 to 5 A square check valve for a vertical outlet pipe of a ventilation fan includes a square-structured outer shell 1. A left valve plate 3 and a right valve plate 4 are rotatably mounted inside the outer shell 1. A rotating shaft 7 passes through both the left and right valve plates 3 and 4, and the rotating shaft 7 is off-center on both the left and right valve plates 3 and 4. The distance from the rotating shaft 7 to the end of the right valve plate 4 is less than half the sum of the lengths of the left and right valve plates 3 and 4. Limiting members 6 are provided on both sides of the left valve plate 3 and the right valve plate 4 in the closing direction. The limiting members 6 are limiting bosses perpendicular to the valve plate closing direction and are bolted to the inside of the outer shell 1.

[0017] The rotating shaft 7 is provided with an oil injection nozzle 71, which is connected to the fitting gap between the rotating shaft 7 and the outer casing 1.

[0018] A limit block 2 is installed inside the outer casing 1 on one side of the left valve plate 3 in the opening direction.

[0019] The limiting block 2 is provided with a limiting block shock-absorbing pad 21.

[0020] Both the left valve plate 3 and the right valve plate 4 are provided with valve plate sealing gaskets 5 on the side near the closing direction.

[0021] The limiting member 6 has a limiting member sealing gasket 61 inside the outer shell 1. When the left valve plate 3 and the right valve plate 4 are closed, the valve plate sealing gasket 5 contacts the limiting member sealing gasket 61.

[0022] The inner wall of the outer casing 1 has a shaft hole corresponding to the assembly position of the rotating shaft 7. The rotating shaft 7 passes through the shaft hole, and both ends of the rotating shaft 7 are connected to the rotating bearing. The rotating bearing is connected to the outer casing 1 through a flange.

[0023] Working principle The square check valve uses a square outer shell 1 as its mounting carrier. The core moving parts are the left valve plate 3 and the right valve plate 4, which are assembled and rotate together via a pivot 7 that is off-center. The pivot 7 passes through both valve plates, and the distance from the pivot 7 to the end of the right valve plate 4 is less than 1 / 2 of the sum of the lengths of the left valve plate 3 and the right valve plate 4, forming a double valve plate linkage rotation structure. The outer shell 1 has two types of key limiting components: a limiting member 6 perpendicular to the valve plate closing direction, corresponding to the valve plate closing side, and a limiting member sealing gasket 61 on the surface of the limiting member 6, and a valve plate sealing gasket 5 on the valve plate closing side, forming a double sealing structure; and a limiting block 2 located on the inner wall of the outer shell 1 in the valve plate opening direction, with a limiting block shock-absorbing pad 21 on its surface, used to limit the maximum opening angle of the valve plate. In addition, the rotating shaft 7 is equipped with an oil injection nozzle 71, which is connected to the rotating shaft 7 and the housing 1 through the fit clearance and the rotating bearings at both ends of the rotating shaft 7. The bearings are fixed to the shaft hole of the housing 1 through the flange to ensure that the rotating shaft 7 can rotate flexibly for a long time.

[0024] In the initial state, the left and right valve plates 4 naturally droop to the closed position around the rotating shaft 7 under their own gravity, and the valve plate sealing gasket 5 and the limiting component sealing gasket 61 are initially in contact, and the check valve is in a sealed state.

[0025] When the main fan starts and the standby fan stops in the system, airflow enters the square check valve on the main fan side from the main fan outlet along the vertical pipeline, triggering the following actions: When the valve plate is opened, the airflow impacts the windward surfaces of the left and right valve plates 4. Since the rotating shaft 7 is off-center, the force exerted by the airflow on the left valve plate 3 is greater than the force exerted on the right valve plate 4, thus creating an opening torque. This torque is much greater than the closing torque created by the valve plate's own weight, so the valve plate can easily rotate around the rotating shaft 7 in the opening direction.

[0026] After the valve plate rotates to a certain angle, its leeward side (the surface facing away from the airflow direction) will contact the opening limit block 2 inside the outer casing 1. The limit block 2 directly limits the maximum opening angle of the valve plate, avoiding excessive rotation of the valve plate and subsequent closing delay. At the same time, the shock-absorbing pad on the surface of the limit block 2 will buffer the impact force of the valve plate collision, greatly reducing the impact noise when the left valve plate 3 contacts the limit block 2, achieving the advantage of low noise.

[0027] After the valve plate is opened, a complete airflow channel is formed inside the square outer shell 1. The effective cross-sectional area of ​​the airflow channel matches the cross-sectional area of ​​the pipeline well, and there will be no situation where the outlet area decreases and the flow velocity increases suddenly. Therefore, the pressure loss when the airflow passes through is minimal, which has the advantage of low pressure loss.

[0028] Standby fan side seal: Prevents airflow backflow. At this time, the standby fan is in a stopped state, and its outlet check valve is not driven by airflow. The left and right valve plates 4 remain closed under their own gravity. The valve plate sealing gasket 5 and the limiting component sealing gasket 61 are tightly fitted. The airflow pressure difference will further compact the sealing surface, forming a double seal, completely blocking the airflow from the main fan side to backflow through the standby fan pipeline, avoiding system efficiency loss or airflow turbulence.

[0029] When the main fan stops operating and it needs to switch to the standby fan, the device achieves a seamless switch through the linkage of gravity shut-off and airflow opening: After the main fan stops, its outlet airflow disappears, and the valve plate of the main fan-side check valve loses the opening torque of the airflow. Under its own gravity, it rotates around the off-center shaft 7 in the closing direction. Since the rotating bearing of the shaft 7 is regularly lubricated by the grease nipple 71, the valve plate rotates without jamming and quickly closes. The valve plate sealing gasket 5 and the limit component sealing gasket 61 make tight contact again, and the main fan-side check valve closes quickly, preventing outside air or residual airflow in the system from flowing back through the main fan pipeline and maintaining stable internal system pressure.

[0030] After the standby fan starts, the airflow enters the check valve on the standby fan side along its outlet pipe. The airflow acts on the windward surfaces of the left and right valve plates 4, and is again driven to open by the torque advantage of the off-center rotating shaft 7 until it contacts the opening limit block 2. The check valve is then fully open, and the airflow passes smoothly. The entire process requires no manual intervention or electric or pneumatic drive devices; the switching is completed solely by the airflow and the weight of the valve plates, enabling uninterrupted system operation with no additional points of failure. The system is simple in structure, has no fault points, and is reliably sealed.

[0031] The grease nipple 71 allows for the regular addition of grease to lubricate the fit between the rotating shaft 7 and the housing 1, as well as the rotating bearing, ensuring that the valve plate rotates flexibly and preventing switch failure due to friction jamming. When the valve plate is closed, the valve plate sealing gasket 5 and the limiting component sealing gasket 61 are tightly fitted to ensure the sealing effect and prevent gas leakage or backflow. The valve plate opening angle is stabilized to prevent excessive angle from causing closing delay, while the shock-absorbing pad continuously reduces operating noise and maintains low-noise operation of the device.

[0032] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not a limitation on the scope of protection of the present utility model. Based on the technical solution of the present utility model, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present utility model.

Claims

1. A square check valve for a vertical outlet pipe of a ventilation fan, characterized in that, The enclosure includes a square-shaped shell (1), inside which a left valve plate (3) and a right valve plate (4) are rotatably mounted. A rotating shaft (7) passes through the left valve plate (3) and the right valve plate (4). The rotating shaft (7) is distributed off-center on both the left valve plate (3) and the right valve plate (4), and the distance from the rotating shaft (7) to the end of the right valve plate (4) is less than 1 / 2 of the sum of the lengths of the left valve plate (3) and the right valve plate (4). Limiting members (6) are provided on one side of the left valve plate (3) and the right valve plate (4) in the closing direction. The limiting member (6) is a limiting boss perpendicular to the closing direction of the valve plate. The limiting member (6) is installed inside the shell (1) by bolts.

2. The square check valve for the vertical outlet pipe of the ventilation fan according to claim 1, characterized in that, The rotating shaft (7) is provided with an oil injection nozzle (71), which is connected to the rotating shaft (7) and the outer shell (1) through the fitting gap.

3. The square check valve for the vertical outlet pipe of the ventilation fan according to claim 1, characterized in that, A limit block (2) is installed inside the outer casing (1) on one side of the left valve plate (3) in the opening direction.

4. The square check valve for the vertical pipe outlet of the ventilation fan according to claim 3, characterized in that, The limiting block (2) is provided with a limiting block shock absorber (21).

5. The square check valve for the vertical outlet pipe of the ventilation fan according to claim 1, characterized in that, Both the left valve plate (3) and the right valve plate (4) are provided with valve plate sealing gaskets (5) on the side near the closing direction.

6. The square check valve for the vertical pipe outlet of the ventilation fan according to claim 5, characterized in that, The limiting member (6) has a limiting member sealing gasket (61) inside the outer shell (1). When the left valve plate (3) and the right valve plate (4) are closed, the valve plate sealing gasket (5) contacts the limiting member sealing gasket (61).

7. The square check valve for the vertical outlet pipe of the ventilation fan according to claim 1, characterized in that, The inner wall of the outer shell (1) is provided with a shaft hole corresponding to the assembly position of the rotating shaft (7). The rotating shaft (7) passes through the shaft hole and its two ends are connected to the rotating bearing. The rotating bearing is connected to the outer shell (1) through a flange.

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