CN219673417U - Box-type pressure regulating tower - Google Patents

Abstract

The utility model discloses a box-type pressure regulating tower which comprises a valve body, a piston cylinder, a water tank and a water supplementing valve control assembly, wherein the piston cylinder is arranged at the top of the valve body; the piston is arranged as follows: when the pressure in the pipeline is lower than a first threshold value, the piston is in sealing contact with the sealing surface so as to close the diversion channel, and when the pressure in the pipeline is higher than a second threshold value, the lower surface of the piston is upwards moved by the action of water pressure so as to open the diversion channel; the water replenishment valve control assembly is separately arranged from the piston, and is arranged as follows: when the pressure in the pipeline is lower than a second threshold value, water in the water tank flows to the valve body through the water supplementing valve control assembly, and when the pressure in the pipeline is higher than the second threshold value, the water supplementing valve control assembly is in a closed state; the first threshold is higher than the second threshold. The utility model can reduce the height of the pressure regulating tower required by the pipeline with higher pressure, and has low manufacturing cost and high safety.

Description

Box-type pressure regulating tower

Technical Field

The utility model relates to the technical field of pipeline valves, in particular to a box-type pressure regulating tower.

Background

In the pressurized water pipeline and the hydroelectric power pressurized water pipeline, in order to prevent the harm of water hammer, a bidirectional pressure regulating tower and other water hammer preventing devices are often required. Theoretical and numerous engineering practices have shown that bi-directional pressure regulating towers are the most effective and reliable among all water hammer protection devices, however bi-directional pressure regulating towers also have a fatal disadvantage in engineering applications in that the height must be above or equal to the maximum water pressure line of the pipeline where they are located. If the pipeline pressure is not high, a bidirectional pressure regulating tower is not needed, if the pipeline pressure is high, the bidirectional pressure regulating tower is needed, but the water pressure line is high at the moment, so the bidirectional pressure regulating tower is also high, often several tens meters or even hundreds meters, the engineering cost is high, the operation management burden is heavy, the coordination with the surrounding environment is difficult, and the safety of the structure is difficult to ensure.

Disclosure of Invention

Aiming at the defects existing in the prior art, the utility model aims to provide a box type pressure regulating tower. The utility model has novel structural design, can realize higher opening pressure setting through a lower water head, namely, the height of the pressure regulating tower required by a pipeline with higher pressure can be greatly reduced, the manufacturing cost is low, and the safety is high.

In order to solve the technical problems, the utility model is realized by the following technical scheme:

the utility model provides a box-type pressure regulating tower which comprises a valve body, a piston cylinder, a water tank and a water supplementing valve control assembly, wherein the piston cylinder is arranged at the top of the valve body; the piston is arranged to: when the pressure in the pipeline is lower than a first threshold value, the bottom surface of the piston is in sealing contact with the sealing surface so as to close the diversion channel, and when the pressure in the pipeline is higher than a second threshold value, the lower surface of the piston is upwards moved by the action of water pressure so as to open the diversion channel; the water replenishment control assembly is provided separately from the piston, the water replenishment control assembly being provided with: when the pressure in the pipeline is lower than a second threshold value, water in the water tank flows to the valve body through the water supplementing valve control assembly, and when the pressure in the pipeline is higher than the second threshold value, the water supplementing valve control assembly is in a closed state; the first threshold is higher than the second threshold.

The water replenishing valve control assembly is arranged between the valve body and the water tank separately from the piston, and comprises a pipeline arranged between the valve body and the water tank, wherein the on-off of the water replenishing valve control assembly is not used for controlling the piston.

The sealing surface arranged at the bottom of the valve body comprises, but is not limited to, a boss arranged at the bottom of the valve body, and the top surface of the boss is a sealing surface.

Preferably, the piston comprises an upper piston section and a lower piston section which are coaxially arranged and connected up and down, wherein an inner part of the lower surface of the lower piston section can form a seal with the top surface of the sealing surface, and an outer part of the lower surface of the lower piston section is in direct contact with water flow in the valve body.

Further preferably, the lower piston section comprises a first lower piston section and a second lower piston section which are coaxially arranged and connected up and down, wherein the lower surface of the second lower piston section can form a seal with the top surface of the sealing surface, the lower surface of the first lower piston section is in direct contact with the water flow in the valve body, and the ratio of the lower surface area of the second lower piston section to the lower surface area of the first lower piston section is not more than 5%.

Further preferably, the ratio of the water pressure area of the upper surface of the piston to the water pressure area of the lower surface of the piston to the water pressure area of the pipeline is (5-15): 1.

Preferably, a filter screen is arranged on the piston at the position corresponding to the outlet at the upper part of the diversion channel, and the flow area of the filter screen is more than 2 times of that of the diversion channel.

Preferably, the water replenishing valve control assembly comprises a connecting pipe and a one-way valve, wherein the connecting pipe is positioned on the side of the lower water tank, the upper end of the connecting pipe is connected with the lower water tank, the lower end of the connecting pipe is connected with the valve body, the one-way valve is arranged at the joint of the connecting pipe and the valve body, and the one-way valve only allows water flow from the lower water tank to the valve body.

Further preferably, a reserved interface is arranged at the top of the connecting pipe.

Preferably, the water tank comprises an upper water tank and a lower water tank, wherein the bottom of the upper water tank is inserted into the lower water tank and communicated with the lower water tank, and a height adjusting assembly for adjusting the height of the water tank is arranged between the upper water tank and the lower water tank.

Further preferably, the height adjusting assembly comprises a screw, a nut and screw interfaces, wherein the screw is vertically fixed at the top of the lower water tank, the screw interfaces are fixed on the outer wall of the upper water tank and are sleeved on the screw, and the screws on the upper side and the lower side of the screw interfaces are respectively connected with the nut in a threaded manner.

Compared with the prior art, the utility model has the following advantages:

the conventional pressure regulating tower generally integrates the water supplementing valve control assembly and the piston together, and although the integral volume of the pressure regulating tower can be reduced after integration, certain interference exists between the water supplementing valve control assembly and the piston during water supplementing and draining, for example: when the water hammer is suddenly boosted in the pipeline, the water supplementing valve control assembly is required to be closed firstly, then the piston is pushed to release pressure, a certain delay exists, and timely response cannot be achieved. Compared with the traditional pressure regulating tower, the water supplementing valve control assembly and the piston are arranged separately and operate independently without interference, and when the water pressure in the pipeline suddenly changes, the piston and the water supplementing valve control assembly can respond at the first time.

The utility model separates the water supplementing valve control component and the piston, on one hand, in order to realize no interference between the two components, and more importantly, in order to increase the amplification ratio (5-15:1) of the pressure regulating tower, namely, on the basis of keeping the water pressure area on the upper surface of the piston unchanged, the water pressure area on the lower surface of the piston is greatly reduced, and due to the amplification ratio, the higher opening pressure setting can be realized through a lower water head, namely, the same pressure relief function can be realized through a small height of the pressure regulating tower, the height of the pressure regulating tower required by a pipeline with higher pressure is greatly reduced, the manufacturing cost is low, meanwhile, the pressure relief/compensation can be carried out when the pressure of the pipeline rises/falls to a certain value, the occurrence of water hammer is avoided/inhibited, and the safety is high.

Because the linear relation is satisfied between the height of the pressure regulating tower and the opening pressure of the piston, when the opening pressure is adjusted according to the needs in the engineering, the insertion depth between the upper water tank and the lower water tank can be adjusted by adjusting the nut on the screw rod, so that the installation height of the upper water tank is controlled, the height of the pressure regulating tower is adjusted, and the large-scale adjustment of the opening pressure is realized. In addition, be equipped with the rectifying tube of less bore in the top high point department of overflow pipe, when needs carry out the fine setting to the stable liquid level of water tank, can adjust rectifying tube height through rotatory rectifying tube, adjust the liquid level height in the tower, also can realize the little range adjustment to opening pressure.

Drawings

FIG. 1 is a schematic cross-sectional view of an embodiment of the present utility model;

FIG. 2 is a schematic cross-sectional view of a valve body according to an embodiment of the present utility model;

FIG. 3 is a schematic cross-sectional view of a height adjustment assembly according to an embodiment of the present utility model;

FIG. 4 is a schematic diagram illustrating a piston force analysis according to an embodiment of the present utility model;

FIG. 5 is a schematic diagram of a piston force analysis according to another embodiment of the present utility model.

Reference numerals: 1. a valve body; 11. a boss; 110. sealing surfaces; 12. a top flange; 13. a first guide sleeve; 14. a vent hole; 15. a side flange; 2. a piston; 21. the upper section of the piston; 22. a lower section of the piston; 221. a first piston lower section; 222. a second piston lower section; 24. a diversion channel; 25. a filter screen; 3. a piston cylinder; 4. a water tank; 41. a water supply tank; 42. a lower water tank; 43. a height adjustment assembly; 431. a screw; 432. a nut; 433. a screw interface; 44. an overflow pipe; 45. rectifying tube; 5. a water replenishment valve control assembly; 51. a connecting pipe; 52. a one-way valve; 53. reserving an interface; 6. a support leg; 7. and a top cover.

Detailed Description

In order that those skilled in the art will better understand the technical solutions of the present utility model, preferred embodiments of the present utility model will be described below with reference to specific examples, but it should be understood that the drawings are for illustrative purposes only and should not be construed as limiting the present patent; for the purpose of better illustrating the embodiments, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the actual product dimensions; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationship depicted in the drawings is for illustrative purposes only and is not to be construed as limiting the present patent.

As shown in fig. 1-5, the utility model provides a box-type pressure regulating tower, which comprises a valve body 1, a piston 2, a piston cylinder 3, a water tank 4 and a water supplementing valve control assembly 5, wherein the piston cylinder 3 is connected to the top of the valve body 1 in a sealing manner, the piston 2 is arranged in the piston cylinder 3 and forms a sliding fit relationship with the piston, the water tank 4 is connected to the top of the piston cylinder 3 in a sealing manner, and the water supplementing valve control assembly 5 is used for supplementing water in the water tank 4 into the valve body 1 in a one-way manner.

Referring to FIG. 2, in one embodiment:

the valve body 1 is of a T-shaped structure or an angular structure. Side flanges 15 are arranged on the left side and the right side of the valve body 1 and are used for connecting a pressure pipeline and a one-way valve 52; the side flanges 15 may be arranged at 180 ° or 9 °; the top is provided with top flange 12, top flange 12 and piston cylinder 3 fixed connection, and top flange 12 middle part has inlayed first uide bushing 13, and top flange 12 and first uide bushing 13 cooperation part are equipped with sealedly. The top flange 12 is provided with a vent hole 14 for exhausting and supplementing air of the piston cylinder 3 in the travelling process of the piston 2; a boss 11 is arranged at the bottom of the valve body 1 corresponding to the lower part of the piston 2, the top surface of the boss 11 is a sealing surface 110, and the sealing surface 110 is matched with the bottom surface of the piston 2 to form a seal; the outside of the bottom of the valve body 1 is provided with more than three foundation plates, and the foundation plates and the supporting feet 6 are connected to form a device foundation support.

Referring to fig. 4, in one embodiment:

the piston 2 is a stepped hollow cylinder. The middle part of the piston 2 is provided with a flow guide channel 24 in a penetrating way, the piston 2 comprises a piston upper section 21, a first piston lower section 221 and a second piston lower section 222 which are coaxially arranged and sequentially connected from top to bottom, the outer diameters of the piston upper section 21, the first piston lower section 221 and the second piston lower section 222 are sequentially reduced, the piston upper section 21 is positioned in the piston cylinder 3 and slides and is provided with a seal after being matched with the inner wall of the piston cylinder 3, the first piston lower section 221 slides and is provided with a seal after being matched with the first guide sleeve 13, the second piston lower section 222 is positioned in the valve body 1, and the lower surface of the second piston lower section 222 and the sealing surface 110 can form a seal. The ratio of the lower surface area of the second piston lower section 222 to the lower surface area of the first piston lower section 221 is not more than 5%, and the lower surface area of the second piston lower section 222 is designed to be much smaller than the lower surface area of the first piston lower section 221, so that the area of the piston on which the water flow acts at the opening moment is not substantially changed, and the opening action is not affected.

The above-mentioned piston 2 structure makes piston 2 when opening and stabilizing the open state soon, and piston 2 atress satisfies following condition:

HxS _i +G＝PxS ₂

wherein:

h is the height of the liquid level in the water tank and MPa;

S ₁ the water pressure area of the water receiving tank of the piston is mm ² ；

G is the weight of the piston and N;

p is the pressure of the water inlet of the pressure regulating tower and MPa;

S ₂ the area of the piston which is subjected to the water pressure of the pipeline is mm ² ；

According to the equipment structure, the following steps are known:

wherein: d1 is the outer diameter of the upper section of the piston, D2 is the outer diameter of the lower section of the first piston, and D3 is the inner diameter of the diversion channel.

Due to this equilibrium, when P rises, i.e. the line pressure exceeds the opening pressure set by the device (i.e. the first threshold), the piston 2 is opened by upward movement, and the water flow enters the upper tank 4 through the diversion channel and then exits through the funnel into the overflow 44, achieving the function of pressure relief. The ratio of S1 to S2 is the amplification ratio of the voltage regulating tower and is generally between 5 and 15. Due to the amplification, a higher opening pressure setting can be achieved with a lower head. Compared with the traditional bidirectional pressure regulating tower (namely, a high-level communicating vessel), the same pressure relief function can be realized through a small height.

Referring to fig. 5, in one embodiment:

the piston 2 is a stepped hollow cylinder, and the difference between this embodiment and the previous embodiment is that: the piston 2 of this embodiment is a two-step hollow cylinder, and is composed of a piston upper section 21 and a piston lower section 22, the lower surface of the piston lower section 22 is a plane, the inner part of the lower surface of the piston lower section 22 can form a seal with the sealing surface 110, and the outer part of the lower surface of the piston lower section 22 is directly contacted with the water flow in the valve body. The ratio of the area of the inner portion of the lower surface of the lower piston section 22 to the area of the outer portion of the lower surface of the lower piston section 22 may also be designed to be not more than 5%.

Referring to FIG. 1, in one embodiment:

a filter screen 25 is arranged on the piston 2 at the position corresponding to the upper outlet of the diversion channel 24, and the function of the filter screen is to prevent sundries in the top water tank 4 from entering the pipeline. The filter screen 25 is a U-shaped filter screen 25, the flow area of which is more than 2 times of the flow area of the piston 2, so as to reduce the head loss generated when water passes through as much as possible.

Referring to FIG. 1, in one embodiment:

the water tank 4 includes an upper water tank 41 and a lower water tank 42, and the bottom of the upper water tank 41 is inserted into and communicates with the inside of the lower water tank 42. The lower water tank 42 is fixedly connected with the piston cylinder 3 and is provided with a seal at the connection. The inner diameter of the lower water tank 42 is slightly smaller than the inner diameter of the piston cylinder 3, so that the maximum limit position of the upward movement of the piston 2 can be restricted after connection. The lower pipeline of the upper water tank 41 is inserted into the lower water tank 42, a seal is arranged at the matching position, a height adjusting component 43 is arranged at the connecting position of the lower water tank 42 and the upper water tank 41, and the insertion depth of the upper water tank 41 in the lower water tank 42 can be adjusted through the height adjusting component 43, so that the installation height of the upper water tank 41 is controlled. The whole height of the water tank 4 can be adjusted in a large range by adjusting the nut 432 on the screw 431, so that the opening pressure can be adjusted.

As shown in fig. 3, the height adjusting assembly 43 includes a screw 431, a nut 432, and a screw interface 433, wherein the screw 431 is vertically fixed on the top of the lower tank 42, the screw interface 433 is fixed on the outer wall of the upper tank 41 and is sleeved on the screw 431, and the screws 431 on the upper and lower sides of the screw interface 433 are respectively connected with the nut 432 by threads. The whole height of the water tank 4 can be adjusted in a large range by adjusting the nut 432 on the screw 431, so that the opening pressure can be adjusted.

Referring to FIG. 1, in one embodiment:

the water replenishing valve control assembly 5 comprises a connecting pipe 51 and a one-way valve 52, the connecting pipe 51 is positioned on the side of the lower water tank 42, the upper end of the connecting pipe 51 is connected with the lower water tank 42, the lower end of the connecting pipe 51 is connected with the valve body 1, the one-way valve 52 is arranged at the position where the lower end of the connecting pipe is connected with the valve body 1, and the one-way valve 52 only allows water flow to flow from the lower water tank 42 to the valve body 1.

Since the check valve 52 is provided between the water tank 4 and the valve body 1. Therefore, when the pipeline pressure is lower than the pressure value (second threshold value) generated by the water tank 4 on the one-way valve, the one-way valve 52 is opened under the action of the difference between the liquid level of the water tank 4 and the pipeline pressure, so that the water flow in the tower flows into the valve body 1 through the one-way valve 52, enters the pipeline, supplements pipeline medium and prevents negative pressure. The check valve 52 may be various types of check valves 52, and may be installed horizontally or vertically. But must be ensured to be fully opened under the pressure difference of 0.3-0.5 m. The illustrated construction is one of the simplest spring-type check valves 52. Due to the limited height and diameter of the tank 4, there may be a tank 4 that is too small to meet the water make-up requirements of the system. At that point the tank can be externally connected through the reserved interface 53.

An overflow pipe 44 and a rectifying pipe 45 are arranged in the upper water tank 41. The overflow pipe 44 is positioned at the height of the water tank 4, and has an inverted trapezoidal funnel structure, so that when the liquid level exceeds the top of the funnel, the overflow pipe can be turned over and flows out from the overflow port. The rectifying tube 45 has an L-shaped adjustable structure. When the stable liquid level of the water tank 4 needs to be finely adjusted, the height of the rectifying tube 45 can be adjusted by rotating the L-shaped rectifying tube 45, and the liquid level in the tower is adjusted, so that the small-range adjustment of the opening pressure is realized.

By rotating the rectifying tube 45, the normal maximum level of the water tank 4 can be adjusted. The top of the water tank 4 is provided with a top cover 7 for preventing external sundries from entering and falling; and under the working condition of better conditions, a top cover is not required to be arranged.

Based on the structure of the pressure regulating tower, the utility model provides a pressure regulating method of a box-type pressure regulating tower, which comprises the following steps:

when the pressure in the pipeline is between a first threshold value and a second threshold value, the water supplementing valve control assembly (5) and the diversion channel (24) are in a closed state, and the first threshold value is higher than the second threshold value;

when the pressure in the pipeline is higher than a first threshold value, the water supplementing valve control assembly (5) is in a closed state, the piston (2) moves upwards under the action of pipeline water pressure so as to open the diversion channel (24), at the moment, water in the pipeline flows from the diversion channel (24) to the water tank (4) for pressure relief, and the piston (2) moves downwards gradually until the diversion channel (24) is closed along with the decrease of the pressure in the pipeline;

when the pressure in the pipeline is lower than a second threshold value, the diversion channel (24) is in a closed state, the one-way valve (52) is opened under the pressure action of the water tank (4), at the moment, water flow in the water tank (4) flows to the valve body (1) from the connecting pipe (51), and along with the rising of the pressure in the pipeline, the opening angle of the one-way valve (52) is gradually reduced until the one-way valve is closed.

The first threshold value is the sum of the dead weight of the piston and the water pressure generated by the water tank, and the second threshold value is the water pressure generated by the water tank when the one-way valve receives.

Based on the description of the utility model and the drawings, a box-type pressure regulating tower of the utility model can be easily manufactured or used by those skilled in the art, and the positive effects described in the utility model can be produced.

Unless specifically stated otherwise, in the present utility model, if there are terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the positional relationship indicated is based on the positional relationship indicated in the drawings, and is merely for convenience of describing the present utility model and simplifying the description, and it is not necessary to indicate or imply that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, so that the terms describing the positional relationship in the present utility model are merely for exemplary illustration and should not be construed as limitations of the present patent, and it is possible for those skilled in the art to understand the specific meaning of the above terms in conjunction with the drawings and according to the specific circumstances.

Unless specifically stated or limited otherwise, the terms "disposed," "connected," and "connected" herein are to be construed broadly, e.g., they may be fixed, removable, or integral; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

The foregoing description is only a preferred embodiment of the present utility model, and is not intended to limit the present utility model in any way, and any simple modification, equivalent variation, etc. of the above embodiment according to the technical matter of the present utility model fall within the scope of the present utility model.

The above is only a preferred embodiment of the present utility model, but the present utility model is not limited to the above-described specific embodiment. Modifications, additions, or substitutions are possible, without departing from the scope of the utility model as disclosed in the accompanying claims.

Claims (9)

1. The utility model provides a box pressure regulating tower, includes valve body (1), piston (2), piston cylinder (3), water tank (4) and moisturizing valve control assembly (5), its characterized in that: a sealing surface (110) is arranged at the bottom of the valve body (1) below the piston (2), and a diversion channel (24) is arranged in the middle of the piston (2) in a penetrating way; the piston (2) is arranged to: when the pressure in the pipeline is lower than a first threshold value, the bottom surface of the piston (2) is in sealing contact with the sealing surface (110) so as to close the diversion channel (24), and when the pressure in the pipeline is higher than the first threshold value, the lower surface of the piston (2) is upwards moved by the action of water pressure so as to open the diversion channel (24); the water replenishment control assembly (5) is arranged separately from the piston (2), the water replenishment control assembly (5) being arranged to: when the pressure in the pipeline is lower than a second threshold value, water in the water tank (4) flows to the valve body (1) through the water supplementing valve control assembly (5), and when the pressure in the pipeline is higher than the second threshold value, the water supplementing valve control assembly is in a closed state; the first threshold is higher than the second threshold.

2. The box-type pressure regulating tower according to claim 1, wherein: the piston (2) comprises an upper piston section (21) and a lower piston section (22) which are coaxially arranged and connected up and down, wherein the inner part of the lower surface of the lower piston section (22) can form a seal with the top surface of the sealing surface (110), and the outer part of the lower surface of the lower piston section is in direct contact with water flow in the valve body (1).

3. The box-type pressure regulating tower according to claim 2, wherein: the lower piston section (22) comprises a first lower piston section (221) and a second lower piston section (222) which are coaxially arranged and are connected up and down, the lower surface of the second lower piston section (222) can form a seal with the top surface of the sealing surface (110), the lower surface of the first lower piston section (221) is in direct contact with water flow in the valve body (1), and the ratio of the lower surface area of the second lower piston section (222) to the lower surface area of the first lower piston section (221) is not more than 5%.

4. The box-type pressure regulating tower according to claim 2, wherein: the ratio of the water pressure area of the upper surface of the piston (2) to the water pressure area of the lower surface of the piston (2) to the water pressure area of the pipeline is (5-15): 1.

5. The box-type pressure regulating tower according to claim 1, wherein: the piston (2) is provided with a filter screen (25) at the position corresponding to the upper outlet of the diversion channel (24), and the overflow area of the filter screen (25) is more than 2 times of that of the diversion channel (24).

6. The box-type pressure regulating tower according to claim 1, wherein: the water tank (4) comprises an upper water tank (41) and a lower water tank (42), wherein the bottom of the upper water tank (41) is inserted into the lower water tank (42) and communicated with the lower water tank, and a height adjusting component (43) for adjusting the height of the water tank (4) is arranged between the upper water tank (41) and the lower water tank (42).

7. The box-type pressure regulating tower according to claim 6, wherein: the water supplementing valve control assembly (5) comprises a connecting pipe (51) and a one-way valve (52), the connecting pipe (51) is located on the side of the lower water tank (42), the upper end of the connecting pipe (51) is connected with the lower water tank (42), the lower end of the connecting pipe (51) is connected with the valve body (1), the one-way valve (52) is arranged at the joint of the connecting pipe (51) and the valve body (1), and the one-way valve (52) only allows water flow to flow from the lower water tank (42) to the valve body (1).

8. The box-type pressure regulating tower according to claim 7, wherein: the top of the connecting pipe (51) is provided with a reserved interface (53).

9. The box-type pressure regulating tower according to claim 6, wherein: the height adjusting assembly (43) comprises a screw (431), a nut (432) and a screw connector (433), wherein the screw (431) is vertically fixed at the top of the lower water tank (42), the screw connector (433) is fixed on the outer wall of the upper water tank (41) and sleeved on the screw (431), and the screws (431) on the upper side and the lower side of the screw connector (433) are respectively connected with the nut (432) in a threaded manner.