Outlet structure of the discharge pipe for liquid-free seal start-up of a liquid material vacuum conveying system

Abstract

The present invention discloses an outlet structure of a discharge pipe for liquid material vacuum conveying system without liquid seal start-up. This structure is composed of a sealing ball, an arc-shaped hollow track, a discharge pipe outlet section and a baffle. The discharge pipe outlet section is in the shape of a quarter circle, installed in the vertical plane with the outlet axis horizontal, and the sealing ball can move on the arc-shaped hollow track. When the system starts up, there is no liquid material in the discharge pipe. Due to the action of gravity, the sealing ball is located at the lowest point, and the spherical surface is in close contact with the discharge pipe outlet, so air will not enter the conveyor system through the discharge pipe and a vacuum can be established. When the liquid material flows into the discharge pipe and reaches a certain liquid column height, the gravity of the liquid column pushes the sealing ball away and the liquid material flows out, and the system enters the conveying state. When the system shuts down, the sealing ball returns to the lowest point to seal the discharge pipe outlet again. This structure has the characteristics of simplicity and reliability, can meet the requirements of liquid material vacuum conveying system without liquid seal start-up, and is suitable for the field of high-radioactivity liquid material conveying.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum conveying of liquid materials, and specifically to an outlet structure of an outlet pipe for liquid material vacuum conveying system without liquid seal start-up. Background Art

[0002] The liquid material vacuum conveying system has no moving parts and can operate without maintenance for a long time. Therefore, it is suitable for the transportation of highly radioactive liquid materials and has a wide application in the field of nuclear power spent fuel reprocessing.

[0003] As Figure 1 shown, the liquid material vacuum conveying system generally consists of a conveyor, a feeding tank, a receiving tank, a feeding pipe, an outlet pipe, and a vacuum generating device, etc. During normal operation, the inside of the conveyor is under negative pressure (i.e., has a certain degree of vacuum). The liquid material in the feeding tank is lifted into the conveyor, enters the weir opening, and then flows by gravity through the outlet pipe into the receiving tank. When the system is initially started, it is necessary to ensure that air does not enter the system through the feeding pipe and the outlet pipe. Otherwise, the vacuum cannot be established, and the normal conveying state cannot be entered. There must be liquid material in the feeding tank when the system starts. The feeding pipe has a liquid seal, which can prevent air from entering. However, the receiving tank may not have liquid material, and the air cannot be isolated by the liquid seal method. Therefore, a special structure needs to be designed at the outlet of the outlet pipe to ensure that the outlet of the outlet pipe can be sealed when the system starts, and when the liquid column in the outlet pipe reaches a certain height, the seal can be opened and the liquid material can flow out smoothly. Moreover, this structure should be safe and reliable and can operate without maintenance for a long time. Summary of the Invention

[0004] In order to solve the problem of the outlet pipe of the liquid material vacuum conveying system without liquid seal start-up, the present invention proposes an outlet structure of an outlet pipe for liquid material vacuum conveying system without liquid seal start-up. Specifically as follows:

[0005] The outlet structure of the outlet pipe of the liquid material vacuum conveying system consists of a sealing ball, an arc-shaped hollow track, an outlet pipe outlet section, and a baffle. The outlet pipe outlet section is in the shape of a quarter circle, installed in the vertical plane, and the outlet axis is horizontal. The diameter of the sealing ball is slightly larger than the diameter of the outlet of the outlet pipe, and it can roll on the arc-shaped hollow track. The baffle is located at the uppermost end of the track.

[0006] The working principle of this sealing ball type outlet structure is as follows: When the liquid material vacuum conveying system starts without liquid seal, there is no liquid material in the outlet pipe. Due to the gravity, the sealing ball is located at the lowest point, and the spherical surface is in close contact with the outlet of the outlet pipe. Air will not enter the conveyor system through the outlet pipe, and the system can successfully establish a vacuum. As the liquid material continuously enters the outlet pipe, the gravity of the liquid column in the outlet pipe pushes the sealing ball away, and the liquid material flows into the receiving tank, and the system enters the conveying state. When the system stops, the sealing ball returns to the lowest point due to gravity and seals the outlet of the outlet pipe again.

[0007] Preferably, the weight of the sealing ball should be significantly greater than the weight of the liquid discharged, that is, the weight of the sealing ball is much greater than its own buoyancy, so as to prevent the sealing ball from floating or being separated from the arc-shaped hollow track due to the acting force of fluid flow when the liquid level in the receiving tank exceeds the sealing ball.

[0008] Preferably, the sealing ball track adopts an arc-shaped hollow design. When the sealing ball is pushed open by the liquid pressure, the liquid falls directly into the receiving tank without being blocked by the track, with little impact on the sealing ball, and the sealing ball will not move to a very high position on the arc track. More importantly, the hollow design can prevent liquid and slag from accumulating in the track when the system is shut down for a long time, ensuring smooth movement and reliable sealing of the sealing ball. In addition, a baffle is provided at the uppermost end of the arc-shaped hollow track to ensure that the sealing ball does not rush out of the track.

[0009] Preferably, when the sealing ball is in the lowest position, the tangent line of the track and the sealing ball is not horizontal, but has a certain inclination angle with the horizontal direction, so that there is a component of the sealing ball's gravity in the direction towards the outlet of the discharge pipe, ensuring close contact between the sealing ball and the outlet of the discharge pipe and maintaining good sealing.

[0010] The beneficial effects of the present invention are as follows:

[0011] 1) The present invention provides a sealing ball type outlet structure design for the discharge pipe of the liquid vacuum conveying system. With this structure, the liquid vacuum conveying system can start and establish a vacuum in the receiving tank without liquid and without liquid seal in the discharge pipe until it enters the normal conveying state.

[0012] 2) The sealing ball type outlet structure has the characteristics of simple structure and reliable long-term operation, meeting the requirements of long-term maintenance-free operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the liquid vacuum conveying system;

[0014] Figure 2 is a schematic diagram of the sealing ball type outlet structure of the present invention.

[0015] The meanings of the reference numerals in the drawings: 10 - conveyor; 20 - feeding tank; 30 - feeding pipe; 40 - weir short pipe; 50 - discharge pipe; 60 - receiving tank; 100 - sealing ball type outlet structure; 1 - sealing ball; 2 - arc-shaped hollow track; 3 - discharge pipe outlet section; 4 - baffle. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be further described below with reference to the drawings.

[0017] As shown in Figure 1As shown in the figure, the liquid material vacuum conveying system consists of a conveyor 10, a feeding tank 20, a feeding pipe 30, a discharging pipe 50, a receiving tank 60, etc. The feeding pipe 30 and the discharging pipe 50 are respectively connected to the conveyor 10. A weir orifice short pipe 40 is designed in the conveyor 10, and a sealed ball type outlet structure 100 is designed at the end of the discharging pipe 50.

[0018] During normal operation, the inside of the conveyor is under negative pressure. The liquid material is sucked from the feeding tank 20 into the conveyor 10. When the liquid level in the conveyor 10 exceeds the height of the weir orifice short pipe 40, the liquid material flows by gravity through the discharging pipe 50 into the receiving tank 60, thus realizing the conveying of the liquid material.

[0019] As Figure 2 shown in the figure, the sealed ball type outlet structure 100 at the end of the discharging pipe of the liquid material vacuum conveying system is composed of a sealed ball 1, an arc-shaped hollow track 2, an outlet section 3 of the discharging pipe, and a baffle 4. The axis of the outlet section 3 of the discharging pipe is in the shape of a quarter circle, installed in the vertical plane, and the outlet axis is horizontal. The surface of the sealed ball 1 is smooth, and its diameter is slightly larger than the outlet diameter of the discharging pipe. It can roll on the arc-shaped hollow track 2. The port of the outlet section 3 of the discharging pipe is flat and smooth. When the sealed ball 1 is at the lowest point, the spherical surface is in close contact with the outlet of the discharging pipe. A baffle 4 is designed at the highest end of the arc-shaped hollow track 3 to ensure that the sealed ball 1 will not rush out of the track.

[0020] The working principle of the sealed ball type outlet structure is as follows: When the liquid material vacuum conveying system starts without liquid seal, there is no liquid material in the discharging pipe. Due to its own gravity, the sealed ball is at the lowest point, and the spherical surface is in close contact with the port of the outlet section 3 of the discharging pipe. Air will not enter the conveying system through the discharging pipe, and the system can establish a vacuum. As the liquid material enters the discharging pipe and the liquid column reaches a certain height, the gravity of the liquid column in the discharging pipe pushes the sealed ball 1 away, and the liquid material flows into the receiving tank 60, and the system enters the conveying state. When the system stops, the sealed ball 1 returns to the lowest point along the arc-shaped hollow track 2 due to gravity and seals the outlet of the discharging pipe again.

[0021] The arc-shaped hollow track is designed with two advantages: ① The hollow design can avoid the accumulation of liquid and slag in the track during long-term shutdown of the system, ensuring smooth movement and reliable sealing of the sealed ball; ② When the sealed ball is pushed away by the liquid pressure in the discharging pipe, the liquid material can directly fall into the receiving tank without being blocked by the track, with little impact on the sealed ball, and the sealed ball will not move to a very high position on the arc-shaped track, improving the stability and reliability of the system operation.

[0022] Two aspects also need to be noted in the design of the sealed ball type outlet structure:

[0023] ① The weight of the sealed ball needs to be significantly greater than the weight of the liquid material it displaces, that is, the weight of the sealed ball is much greater than its own buoyancy, so as to prevent the sealed ball from being lifted or separated from the arc-shaped hollow track by the fluid flow force. Generally, it is required that the weight of the sealed ball should be more than twice its buoyancy.

[0024] ② When the sealing ball is at the lowest position, the tangent of the track and the sealing ball is not horizontal, but has a certain inclination angle α with the vertical direction, so that there is a component of the gravity of the sealing ball in the direction towards the outlet of the discharge pipe, ensuring that the sealing ball is in close contact with the outlet of the discharge pipe and maintaining good sealing. There is a reasonable range for the value of the α angle. If the value is too small, the gravity component is too small and the sealing force is insufficient. If it is too large, the gravity component is too large and the sealing ball is not easily pushed open by the liquid column. The preferable value range of the α angle is 3° - 5°.

[0025] It should be added that there is no liquid in the discharge pipe when the system starts. In order to prevent air from remaining in the discharge pipe, the starting flow rate should be maintained at a low level and gradually increased to the normal conveying flow rate.

[0026] The above description is only the basic idea and method of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the idea and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An outlet structure of the discharge pipe for the liquid-free seal start-up of a liquid material vacuum conveying system. The liquid material vacuum conveying system is composed of a conveyor (10), a feeding tank (20), a feeding pipe (30), a discharge pipe (50) and a receiving tank (60). The feeding pipe (30) and the discharge pipe (50) are respectively connected to the conveyor (10). A weir orifice short pipe (40) is arranged in the conveyor (10), and a sealed ball type outlet structure (100) is designed at the end of the discharge pipe (50); it is characterized in that: The described sealed ball type outlet structure (100) includes a sealed ball (1), an arc-shaped hollow track (2), an outlet section of the discharge pipe (3), and a baffle (4); the outlet section of the discharge pipe (3) is in a quarter-circular arc shape, installed in a vertical plane, and its outlet axis is horizontal; the diameter of the sealed ball (1) is slightly larger than the outlet diameter of the discharge pipe and can roll on the arc-shaped hollow track (2), the baffle (4) is located at the uppermost end of the arc-shaped hollow track (2), the weight of the sealed ball (1) is greater than the buoyancy force it receives, and when the sealed ball (1) is in the lowest position, the tangent line of the arc-shaped hollow track (2) and the sealed ball (1) forms a certain inclination angle with the horizontal direction.

2. The outlet structure of the discharge pipe for liquid-free seal start-up of a liquid material vacuum conveying system according to claim 1, characterized in that: The described arc-shaped hollow track (2) prevents liquid accumulation and slag retention in the track during long-term shutdown of the system.

3. The outlet structure of the discharge pipe for liquid-free seal start-up of a liquid material vacuum conveying system according to claim 1, characterized in that: The range of values of the inclination angle is 3° - 5°.

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