A bellows-type electric vacuum shut-off valve

Abstract

A bellows-type electric vacuum shut-off valve includes a valve body, the middle of which is connected to a valve seat and a lower housing, with a sealing gasket in the middle; the lower housing is used to position a screw shaft, and an elongated groove is provided on the lower housing, with the screw on the valve disc being engaged in the groove; it also includes a motor reducer, which is connected to a pinion via a key, and a large gear is connected to a clutch via a connecting plate, and the clutch is then connected to the screw shaft via a key, with a handwheel provided at the tail of the screw shaft.

Description

Technical Field

[0001] This invention relates to the field of nuclear vacuum valve technology, and specifically to a bellows-driven electric vacuum shut-off valve. Background Technology

[0002] Currently, all DN25 vacuum shut-off valves used in my country's uranium enrichment centrifuge systems are manually operated. While these valves are simple in structure and low in cost, they are inconvenient to operate. When the system initiates a shut-off response, on-site operation is required, with dedicated personnel assigned to each section or unit. Each person can only operate one valve at a time, preventing simultaneous opening and closing of multiple valves, resulting in low safety and reliability. Furthermore, manual valves are unsuitable for frequent operation within sealed enclosures.

[0003] For valves installed and used within the sealed enclosure, the valves must be as lightweight and compact as possible, operate safely and reliably, have good corrosion resistance, and be electrically operated to ensure that multiple valves can be opened and closed simultaneously. The opening and closing signals of the electrically operated valves should be routed to the control room to ensure rapid valve opening and closing within the control room. Summary of the Invention

[0004] The purpose of this invention is to provide an electric bellows vacuum shut-off valve to solve the problem of difficulty in operating multiple valves simultaneously in special situations such as uranium enrichment systems and operations inside sealed enclosures, thereby meeting the installation and use requirements of valves within sealed enclosures and ensuring the safety and reliability of the process system.

[0005] The technical solution of the present invention is as follows: A bellows electric vacuum shut-off valve includes a valve body, the middle part of which is connected to a valve seat and a lower housing, and a sealing gasket is provided in the middle; the lower housing is used to position the screw shaft, and an elongated groove is provided on the lower housing, and the screw on the valve disc is stuck in the groove;

[0006] It also includes a motor reducer, which is connected to a pinion via a key, and a large gear is connected to a clutch via a connecting plate. The clutch is then connected to a screw shaft via a key, and a handwheel is provided at the end of the screw shaft.

[0007] The screw shaft is connected to the valve disc, and the screw shaft is positioned on the valve body through the bearing. The lower housing is connected to the valve body and also to the gearbox. The pinion and gear are placed in the gearbox. The gearbox is connected to the upper housing. The clutch is placed in the upper housing. The cover covers the upper housing.

[0008] The valve body is bolted to the valve seat and the lower housing.

[0009] The lower housing provides protection for the bellows assembly, which consists of the valve disc, valve seat, and bellows.

[0010] When the screw shaft rotates, the valve disc and bellows move up and down in a straight line because the screw on the valve disc is stuck in the groove, causing the valve disc and its sealing ring to separate from or press against the sealing surface on the valve body.

[0011] The motor reducer drives the pinion gear, which meshes with the large gear for transmission. The large gear rotates the clutch through the connecting plate, thereby driving the screw shaft to rotate. When the screw shaft rotates until the sealing ring on the valve disc contacts the sealing surface of the valve body, the valve is closed.

[0012] The screw shaft and valve disc are connected by threads.

[0013] The lower housing is connected to the valve body by screws.

[0014] It also includes a lid, which covers the upper box.

[0015] The clutch is a type that engages when energized and disengages when de-energized. That is, when the power is off, the upper and lower parts of the clutch are separated. At this time, rotating the handwheel at the end of the screw shaft will cause the upper part of the clutch to rotate with the screw shaft 6, while the lower part connected to the large gear remains stationary.

[0016] The significant advantages of this invention are: the valve enables rapid shut-off of the process system, saving manual operation costs and ensuring the stability of the process system operation; the O-ring sealing structure ensures the sealing of the powder medium; the clutch ensures that the relevant transmission components of the motor do not rotate when the valve is manually operated, preventing reverse current and ensuring the safety and reliability of the valve; the bellows provides sealing for the transmission components, ensuring no external leakage. The valve is small in size, has low installation requirements, and is easy to install and operate within a sealed enclosure. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the bellows-driven electric vacuum shut-off valve described in this invention;

[0018] In the diagram: 1-Valve body 2-Sealing ring 3-Valve disc 4-Sealing gasket A 5-Valve seat 6-Screw 7-Bellboard 8-Lower housing 9-Motor 10-Gearbox 11-Pinary gear 12-Upper housing 13-Cover 14-Handwheel 15-Clutch 16-Key 17-Connecting plate 18-Large gear 19-Pointer 20-Screw 21-Limit switch 22-Cover 23-Blind plate 24-Sealing gasket 25-Bolt. Detailed Implementation

[0019] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0020] A bellows-driven electric vacuum shut-off valve includes a valve body 1. Both ends of the valve body 1 are connected to bolts 25 and process pipelines via sealing gaskets 24. During installation, the flow direction of the valve should be consistent with the flow direction of the medium. The middle part of the valve body 1 is bolted to the valve seat 5 and the lower housing 8, with a sealing gasket 4 in between to ensure the valve's sealing performance. The lower housing 8 is used to position the screw shaft 6 and protects the bellows assembly composed of the valve disc 3, valve seat 5, and bellows 7. An elongated groove is provided on the lower housing 8, and the screw 20 on the valve disc 3 is engaged in the groove, allowing the valve disc 3 and bellows 7 to move only up and down, not rotate. When the screw shaft 6 rotates, because the screw 20 on the valve disc 3 is engaged in the groove, the valve disc 3 and bellows 7 can only move linearly up and down, causing the valve disc 3 and its sealing ring 2 to disengage from or press against the sealing surface on the valve body 1, thereby opening and closing the valve. When screw-20 touches the open limit switch, the motor is de-energized and the valve opens; when screw-20 touches the close limit switch, the motor is de-energized and the valve closes.

[0021] The valve stem is rotated via electric or manual operation. The drive unit mainly includes: a motor reducer-9 connected to a pinion-11 via key 16, which meshes with the main gear; a large gear-18 not directly connected to the screw shaft-6, but connected to a clutch-15 via a connecting plate-17; the clutch-15 is then connected to the screw shaft-6 via a key; and a handwheel-14 is located at the tail of the screw shaft-6. The principle of electric drive is as follows: the motor reducer-9 drives the pinion-11, which meshes with the large gear-18. The large gear-18, via the connecting plate-17, causes the clutch-15 to rotate, thereby driving the screw shaft-6 to rotate. When the screw shaft-6 rotates until the sealing ring-2 on the valve disc-3 contacts the sealing surface of the valve body-1, the valve closes. When the motor reverses, it drives in the opposite direction, opening the valve.

[0022] Because the selected clutch-15 is an energized engagement type that disengages when power is off, meaning that the upper and lower parts of the clutch are separated when power is off, rotating the handwheel-14 at the end of the screw shaft-6 causes the upper part of the clutch-15 to rotate with the screw shaft-6, while the lower part of the connecting gear-18 remains stationary, thus fulfilling the requirement that the motor does not move during manual operation. The handwheel-14 directly drives the screw shaft-6 to rotate, thereby opening and closing the valve and meeting the requirements of manual operation.

[0023] In the above structure, the screw shaft-6 and the valve disc-3 are connected by threads. The screw shaft-6 is positioned on the valve body-1 by bearings. The lower housing-1 is connected to the valve body-1 by screws and is also connected to the gearbox housing-10. The pinion-11 and the gear-18 are placed in the gearbox housing-10. The gearbox housing-10 is connected to the upper housing-12. The clutch-15 is placed in the upper housing-12. Finally, the upper housing is covered with the cover-13 to form a closed cavity for the transmission structure.

[0024] Approximately 80% of the process piping is DN25. To meet the material cutoff requirements, multiple DN25 gate valves of the corresponding diameter must be installed. Previously used gate valves were all manually operated and did not meet the requirement for rapid shut-off. The new process system requires multiple pipelines to simultaneously and rapidly unload or cut off material. Furthermore, all pipelines and valves in this system are housed in a sealed enclosure with limited space. Therefore, the valves must be as small as possible, and manual operation must be minimized, allowing for valve operation from the control room.

[0025] The design requires all process piping, valves, and equipment to be operated within a sealed enclosure. Typically, the motors and reducers used with valves are large and heavy, hindering installation and operation within the enclosure. This development utilizes a coreless motor with a planetary gear reducer, reducing the structural size of the motor and reducer. This is the first time a DC motor has been used to drive vacuum valves in a uranium enrichment system, mitigating safety hazards associated with AC motor power, saving space, and meeting installation requirements. The reduction gear controls valve closing time to within 3 seconds, enabling rapid valve opening and closing and ensuring quick process system shutdown. The motor and reducer have a diameter of φ42mm and a total length of 136mm, making them compact while providing the necessary closing torque for the valves, facilitating system piping layout.

[0026] To allow for manual operation of the electric valve when necessary, a clutch is installed on the valve. A jaw clutch, which engages when energized and disengages when de-energized, is selected. When the valve is energized, the motor starts, the clutch engages, and the motor rotation drives the gear pair to rotate. The large gear rotates, which in turn drives the clutch, which in turn drives the screw to rotate, thus opening and closing the valve. When the valve is de-energized, the clutch is disengaged, and the valve is opened and closed by turning the screw with a handwheel. In this state, the gear pair does not rotate, and the motor and reducer shaft do not rotate, achieving complete separation of manual and electric operation.

[0027] Since the screw is a transmission component, reliable measures are required to ensure dynamic sealing. The design employs a bellows seal, connecting the valve disc to the valve seat. A trapezoidal threaded blind hole is opened in the center of the valve disc, connecting to the screw, thus isolating the screw's dynamic seal to the outside of the channel. The bellows is made of stainless steel and uses a double-layer structure.

[0028] The system's production process easily generates powder media. The manual valves, which use PTFE gaskets for flat seals, are prone to incomplete closure and internal leakage in powder-rich environments. To meet sealing requirements and reduce powder accumulation, a line seal with O-rings is adopted. A trapezoidal groove for the O-ring is provided on the valve disc; the O-ring is inserted into the groove, and a seal is achieved by compressing the O-ring. This sealing method is suitable for powder-rich environments and helps ensure valve sealing requirements.

Claims

1. A bellows motor-operated vacuum stop valve characterized by: It includes valve body (1), the middle part of valve body (1) is connected with valve seat (5), lower box (8), and the middle part is equipped with sealing gasket (4);Lower box (8) is used to position screw shaft (6), and long circular groove is arranged on lower box (8), and screw (20) on valve clapper (3) is clamped in the groove; It also includes motor reducer (9), motor reducer (9) is connected with pinion (11) through key (16), and large gear (18) is connected with clutch (15) through connecting plate (17), clutch (15) is connected with screw shaft (6) through key (16), and hand wheel (14) is arranged on the tail of screw shaft (6); Screw shaft (6) is connected with valve clapper (3), screw shaft (6) is positioned on valve body (1) through bearing, lower box (8) is connected with valve body (1), and is connected with gear box (10) at the same time, pinion (11) and large gear (18) are arranged in gear box (10), gear box (10) is connected with upper box (12), clutch (15) is arranged in upper box (2), and cover (13) covers upper box (12); Motor reducer (9) drives pinion (11), pinion (11) is engaged with large gear (18) to drive, and large gear (18) rotates clutch (15) through connecting plate (17), so as to drive screw shaft (6) to rotate, when screw shaft (6) rotates to the sealing ring (2) on valve clapper (3) and the sealing surface of valve body (1) contact, the valve is closed. Clutch (15) is the type of energizing attraction and separation, when power off, the upper and lower parts of clutch (15) are separated, at this time, the end hand wheel (14) of rotating screw shaft (6) is rotated, so that the upper half of clutch (15) rotates with screw shaft (6), and the lower half of connecting large gear (18) is not moved.

2. A bellows motor-operated vacuum shut-off valve according to claim 1, characterized in that: The middle part of valve body (1) is connected with valve seat (5) and lower box (8) by bolts.

3. A bellows motor-operated vacuum shut-off valve according to claim 1, characterized in that: Lower box (8) protects corrugated pipe assembly composed of valve clapper (3), valve seat (5) and corrugated pipe (7).

4. A bellows motor-operated vacuum shut-off valve according to claim 1, characterized in that: When screw shaft (6) rotates, because screw (20) on valve clapper (3) is clamped in the groove, valve clapper (3) and corrugated pipe (7) move up and down linearly, so that valve clapper (3) and sealing ring (2) on it are separated or pressed on the sealing surface of valve body (1).

5. A bellows motor-operated vacuum shut-off valve according to claim 1, characterized in that: Screw shaft (6) is connected with valve clapper (3) by thread.

6. A bellows motor-operated vacuum shut-off valve according to claim 1, characterized in that: Lower box (8) is connected with valve body (1) by screw.

7. A bellows motor-operated vacuum shut-off valve according to claim 1, characterized in that: It also includes cover (13), which covers upper box (12).

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