Vacuumizing system of low-temperature transmission pipeline

Abstract

The utility model belongs to the technical field of vacuum systems, and mainly relates to a vacuumizing system of a low-temperature transmission pipeline, which comprises the low-temperature transmission pipeline with an inner cavity, a circulating heating fan, a liquid nitrogen cold well, a roots secondary vacuum pump and a molecular pump, hot air generated by the circulating heating fan circularly flows in the inner cavity of the low-temperature transmission pipeline; the Roots two-stage vacuum pump and the molecular pump are connected with an inner cavity of the low-temperature transmission pipeline so as to extract air in the inner cavity of the low-temperature transmission pipeline. Under the working condition of low vacuum degree, only the roots two-stage vacuum pump is used for extracting air in the inner cavity, and under the working condition of high vacuum degree, the liquid nitrogen cold well is used for reducing the amount of water vapor entering the system, and the roots two-stage vacuum pump and the molecular pump are simultaneously used for extracting air in the inner cavity, so that air in the inner cavity can be extracted according to different vacuum degrees. Different types of vacuum pumps are switched, the pumping speed of the whole vacuum pumping system is increased, and the impurity pollution probability of a high-vacuum pumping pipeline is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to vacuum system technical field, mainly relates to a kind of low temperature transmission pipeline's vacuum system. BACKGROUND

[0002] The existing low temperature transmission line evacuation system has the following shortcomings: 1. The same type of vacuum pump and the same pipeline system are used for the high vacuum and low vacuum of the low temperature transmission line sandwich. During the entire evacuation process, the vacuum pump has a large loss in pumping speed. Without protective measures, when the vacuum degree of the sandwich is low, small solid particles and water or oil stains in the transmission line sandwich may enter the evacuation pipeline and the vacuum pump cavity, causing irreversible damage to the vacuum system. 2. The external heating method can improve the evacuation efficiency of the low temperature pipeline sandwich to some extent. However, due to the structure of the low temperature transmission line, the multi-layer winding structure is attached to the medium inner tube and does not contact the outer wall. After the sandwich starts to evacuate, the convective heat in the sandwich will gradually decrease, directly causing the heating efficiency of the external heating method for the aluminum foil winding layer to be greatly reduced. The structure with the largest actual outgassing rate in the low temperature transmission line sandwich is the aluminum foil winding layer. The existing evacuation system can only increase the evacuation time and the external heating time to achieve the required sandwich vacuum degree and leakage outgassing rate.

[0003] The existing evacuation system cannot achieve the maximum evacuation efficiency of the vacuum pump itself and may cause irreversible damage to the evacuation system. In addition, due to the low evacuation efficiency, the evacuation time is long and the energy consumption is high. INVENTION CONTENTS

[0004] The utility model provides a kind of low temperature transmission pipeline's vacuum system to solve the low evacuation efficiency in prior art.

[0005] To solve the above problems, the utility model adopts the following technical solutions:

[0006] A kind of low temperature transmission pipeline's vacuum system, comprising:

[0007] Low temperature transmission pipeline, with inner cavity;

[0008] Circulating heating fan, the two ends of the inner cavity are communicated, so that the hot air generated by circulating heating fan circulates in the inner cavity of low temperature transmission pipeline;

[0009] Roots two-stage vacuum pump, connected to the inner cavity of low temperature transmission pipeline, to extract air in the inner cavity of low temperature transmission pipeline;

[0010] Molecular pump, connected with liquid nitrogen cold well, liquid nitrogen cold well is connected to the inner cavity of low temperature transmission pipeline, to extract air in the inner cavity of low temperature transmission pipeline.

[0011] The application has the beneficial effects that: in the working condition of low vacuum degree, only the Roots two-stage vacuum pump is used to extract air in the inner cavity; in the working condition of high vacuum degree, the amount of water vapor entering the system is reduced by using the liquid nitrogen cold well, and the Roots two-stage vacuum pump and the molecular pump are used to extract air in the inner cavity together, so that different types of vacuum pumps are switched according to different vacuum degrees, the overall pumping speed of the vacuum pumping system is improved, and the probability of impurity pollution of the high-vacuum evacuation pipeline is reduced; meanwhile, the circulating heating fan of the low-temperature transmission pipeline is increased, the heating efficiency is improved, the air release is accelerated, the overall evacuation time is shortened, and the energy consumption and the production cost of enterprises are reduced.

[0012] Further, a first valve is connected between the Roots two-stage vacuum pump and the low-temperature transmission pipeline to control the on-off connection between the Roots two-stage vacuum pump and the low-temperature transmission pipeline.

[0013] A second valve is connected between the molecular pump and the low-temperature transmission pipeline to control the on-off connection between the molecular pump and the low-temperature transmission pipeline.

[0014] The first valve and the second valve control the switching of different types of vacuum pumps.

[0015] Further, the second valve is located between the liquid nitrogen cold well and the low-temperature transmission pipeline.

[0016] Further, an air extraction pipe is arranged on the low-temperature transmission pipeline, the air extraction pipe communicates with the inner cavity of the low-temperature transmission pipeline, and the Roots two-stage vacuum pump and the molecular pump are connected to the inner cavity of the low-temperature transmission pipeline through the air extraction pipe.

[0017] The number of interfaces on the low-temperature transmission pipeline is reduced, and the sealing performance of the low-temperature transmission pipeline is ensured.

[0018] Further, the low-temperature transmission pipeline comprises a medium inner pipe and a sandwiched outer pipe which are coaxially sleeved, the inner cavity is arranged in the medium inner pipe, the sandwiched outer pipe is sleeved on the outer side of the medium inner pipe, and a spacing space is arranged between the medium inner pipe and the sandwiched outer pipe, and a support is arranged in the spacing space to support the sandwiched outer pipe on the medium inner pipe.

[0019] Further, a winding layer is arranged on the outer side of the sandwiched outer pipe.

[0020] Further, the winding layer is composed of aluminum foil wound on the outer side of the sandwiched outer pipe.

[0021] The circulating heating fan of the low-temperature transmission pipeline can improve the heating efficiency of the aluminum foil winding layer, accelerate the air release of the winding layer, shorten the overall evacuation time, and reduce the energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and other objects, features and advantages of the present embodiments will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which:

[0023] Figure 1 Fig. 1 is a structural schematic diagram of the present application.

[0024] Legend of reference signs:

[0025] 1, low temperature transmission pipeline; 2, circulating heating fan; 3, Roots two-stage vacuum pump; 4, molecular pump; 5, liquid nitrogen cooling well; 6, first valve; 7, second valve; 8, air extraction pipe; 9, first pipeline; 10, second pipeline. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. It should be appreciated by those skilled in the art that the embodiments described below are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0027] The various non-limiting embodiments of the present application will be specifically introduced below. Any element quantity in the drawings is used for example but not limitation, and any naming is only used for distinction, but does not have any limiting meaning. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0028] As shown in Fig. 1, a vacuum extraction system of a low temperature transmission pipeline includes a low temperature transmission pipeline 1, a circulating heating fan 2, a Roots two-stage vacuum pump 3 and a molecular pump 4. The low temperature transmission pipeline 1 has an inner cavity, and the Roots two-stage vacuum pump 3 and the molecular pump 4 extract air in the inner cavity of the low temperature transmission pipeline 1. Figure 1 The circulating heating fan 2 in the present embodiment communicates two ends of the inner cavity, so that the hot air generated by the circulating heating fan 2 circulates in the inner cavity of the low temperature transmission pipeline 1. The air outside will not enter the circulating heating fan 2, and the air outside will not enter the inner cavity of the low temperature transmission pipeline 1. The circulating flow of the hot air generated by the circulating heating fan 2 in the inner cavity of the low temperature transmission pipeline 1 in the present embodiment means that the hot air circulates between the circulating heating fan 2 and the inner cavity of the low temperature transmission pipeline 1.

[0029]

[0030] ​The Roots two-stage vacuum pump 3 in the embodiment is connected to the inner cavity of the low-temperature transmission pipeline 1 to extract air in the inner cavity of the low-temperature transmission pipeline 1. The Roots two-stage vacuum pump 3 can be used to extract air in the inner cavity in the low-vacuum condition. The molecular pump 4 is connected to the liquid nitrogen cold well 5, and the liquid nitrogen cold well 5 is connected to the inner cavity of the low-temperature transmission pipeline 1 to extract air in the inner cavity of the low-temperature transmission pipeline 1. When in the high-vacuum condition, the liquid nitrogen cold well 5 is used to reduce the amount of water vapor entering the system, and the Roots two-stage vacuum pump 3 and the molecular pump 4 are used to extract air in the inner cavity together. Thus, different types of vacuum pumps are switched according to different vacuum degrees, the overall pumping speed of the vacuum pumping system is improved, the probability of impurity pollution in the high-vacuum pumping pipeline is reduced, the circulating heating fan 2 of the low-temperature transmission pipeline 1 is increased, the heating efficiency is improved, the air release is accelerated, the overall pumping time is shortened, the energy consumption is reduced, and the production cost of the enterprise is reduced.

[0031] The Roots two-stage vacuum pump 3 in the embodiment is connected to the inner cavity of the low-temperature transmission pipeline 1 through the first pipeline 9, and the first valve 6 is arranged on the first pipeline 9. The first valve 6 can control the opening and closing of the first pipeline 9, thereby controlling the opening and closing between the Roots two-stage vacuum pump 3 and the low-temperature transmission pipeline 1. The molecular pump 4 is connected to the inner cavity of the low-temperature transmission pipeline 1 through the second pipeline 10, and the second valve 7 is arranged on the second pipeline 10. The second valve 7 is arranged between the liquid nitrogen cold well 5 and the low-temperature transmission pipeline 1, and the second valve 7 can control the opening and closing of the second pipeline 10, thereby controlling the opening and closing between the molecular pump 4 and the low-temperature transmission pipeline 1. The first valve 6 and the second valve 7 are used to control the switching of different types of vacuum pumps. The first valve 6 and the second valve 7 in the embodiment have the same structure, and the first valve 6 and the second valve 7 are prior art, which will not be described in detail.

[0032] The low-temperature transmission pipeline 1 is provided with the air extraction pipe 8, which is connected to the inner cavity of the low-temperature transmission pipeline 1. The Roots two-stage vacuum pump 3 and the molecular pump 4 are both connected to the inner cavity of the low-temperature transmission pipeline 1 through the air extraction pipe 8. Thus, the number of interfaces on the low-temperature transmission pipeline 1 is reduced, the sealing performance of the low-temperature transmission pipeline 1 is ensured, and the probability of air leakage of the low-temperature transmission pipeline 1 is reduced.

[0033] The low-temperature transmission pipeline 1 in the embodiment includes a medium inner pipe and a sandwich outer pipe coaxially sleeved. The sandwich outer pipe is sleeved outside the medium inner pipe, and a spacing space is formed between the medium inner pipe and the sandwich outer pipe. A support member is arranged in the spacing space to support the sandwich outer pipe on the medium inner pipe.

[0034] The outer side of the sandwich outer pipe is provided with a winding layer. The winding layer in the embodiment is composed of aluminum foil wound outside the sandwich outer pipe. The circulating heating fan 2 of the low-temperature transmission pipeline 1 can improve the heating efficiency of the aluminum foil winding layer, accelerate the air release of the winding layer, shorten the overall pumping time, reduce the energy consumption, and reduce the production cost of the enterprise.

Claims

1. A vacuum system for a cryogenic transmission pipeline, characterized in that, include: Low-temperature transmission pipeline with an internal cavity; A circulating heating fan is connected to both ends of the inner cavity so that the hot air generated by the circulating heating fan circulates in the inner cavity of the low-temperature transmission pipeline; A Roots two-stage vacuum pump is connected to the inner cavity of the cryogenic transmission line to extract air from the inner cavity of the cryogenic transmission line. A molecular pump is connected to a liquid nitrogen cooling well, which is connected to the inner cavity of a cryogenic transmission pipeline to extract air from the inner cavity of the cryogenic transmission pipeline.

2. The vacuum system for a cryogenic transmission pipeline according to claim 1, characterized in that, A first valve is connected between the Roots secondary vacuum pump and the cryogenic transmission pipeline to control the on / off connection between the Roots secondary vacuum pump and the cryogenic transmission pipeline. A second valve is connected between the molecular pump and the cryogenic transmission line to control the on / off state of the connection between the molecular pump and the cryogenic transmission line.

3. The vacuum system for a cryogenic transmission pipeline according to claim 2, characterized in that, The second valve is located between the liquid nitrogen cold well and the cryogenic transmission pipeline.

4. The vacuum system for a cryogenic transmission pipeline according to claim 3, characterized in that, The cryogenic transmission pipeline is equipped with an extraction pipe, which connects to the inner cavity of the cryogenic transmission pipeline. Both the Roots secondary vacuum pump and the molecular pump are connected to the inner cavity of the cryogenic transmission pipeline through the extraction pipe.

5. A vacuum system for a cryogenic transmission pipeline according to any one of claims 1-4, characterized in that, The cryogenic transmission pipeline includes a coaxially sleeved inner medium tube and a sandwiched outer tube. The inner cavity is located in the inner medium tube, and the sandwiched outer tube is sleeved on the outside of the inner medium tube. There is a gap between the inner medium tube and the sandwiched outer tube, and a support is provided in the gap to support the sandwiched outer tube on the inner medium tube.

6. The vacuum system for a cryogenic transmission pipeline according to claim 5, characterized in that, The outer side of the sandwiched outer tube is provided with a winding layer.

7. The vacuum system for a cryogenic transmission pipeline according to claim 6, characterized in that, The winding layer is formed by wrapping aluminum foil around the outside of the interlayer outer tube.

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