CN1304799C - Dual-way air-intake vascular refrigeator with corrugated pipe direct-current blocking-up structure - Google Patents

Abstract

The invention discloses a two-way intake type pulse tube refrigerator with a bellows direct current blocking structure. It includes a compressor connected in sequence, a heat exchanger at the hot end of the regenerator, a regenerator, a cold head, a pulse tube, a heat exchanger at the hot end of the pulse tube, an orifice valve, and a gas store. There is a bellows DC blocking structure, and a capillary is arranged between the air inlet of the regenerator and the hot end of the pulse tube. The invention not only maintains the flow rate of the original second intake air flowing through the regenerator through the diversion part, reduces the loss of the regenerator, but also improves the ability to adjust the phase relationship between the pressure wave and the velocity wave of the alternating flow of the working medium in the refrigerator. It has the advantages of strengthening the pressure amplitude in the pulse tube, and at the same time blocks the direct current flow along the regenerator, the pulse tube and the second intake circuit, eliminates the influence of the direct current on the cooling temperature and cooling capacity, and solves the problem of the traditional two-way intake pulse. Operational stability problems due to direct flow in tube refrigerators.

Description

Two-way intake pulse tube refrigerator with bellows DC blocking structure

technical field

The invention relates to a two-way intake type pulse tube refrigerator with a bellows direct current blocking structure.

Background technique

Because the low-temperature moving part-the ejector is removed, the pulse tube refrigerator avoids problems such as sliding seals and mechanical wear at low temperatures, and is expected to become a low-cost, low-vibration, stable and reliable long-life low-temperature refrigerator. Especially with the proposal and successful application of phase modulation structures such as small holes, gas banks, and two-way air intake, the cooling temperature of pulse tube refrigerators has been continuously reduced, and the cooling capacity and cooling efficiency have also been greatly improved, which is close to or even exceeded in some working conditions. Traditional regenerative cryogenic refrigerators (such as G-M refrigerators, Stirling refrigerators, etc.) have been practically used in the cooling of superconducting devices and infrared equipment, as well as in the liquefaction of cryogenic fluids. However, the two-way inlet phase modulation structure connects the inlet of the regenerator and the hot end of the pulse tube through a pipeline to form a second inlet, which improves the efficiency of the regenerator by bypassing part of the working fluid flow through the regenerator , while enhancing the ability to adjust the phase relationship between the pressure wave and the velocity wave inside the refrigerator, and strengthening the pressure wave amplitude in the pulse tube, it also forms a closed loop composed of the regenerator, the pulse tube and the second intake air. When the refrigerator is running , there may be an additional net mass flow from the regenerator through the cold head to the pulse tube or the opposite direction in the loop, also known as Gedeon DC. The existence of Gedeon direct current not only affects the cooling temperature and loses part of the cooling capacity, but also causes the operation state of the refrigerator to be unstable, which hinders the practical progress of the pulse tube refrigerator.

Contents of the invention

The object of the present invention is to provide a two-way intake pulse tube refrigerator with a bellows direct current blocking structure.

It includes a compressor connected in sequence, a heat exchanger at the hot end of the regenerator, a regenerator, a cold head, a pulse tube, a heat exchanger at the hot end of the pulse tube, an orifice valve, and a gas store. There is a bellows DC blocking structure, and a capillary is arranged between the air inlet of the regenerator and the hot end of the pulse tube.

The bellows DC blocking structure is a section of bellows with one end closed, which is located in the vessel and arranged coaxially with the vessel. The tube lumen communicates with the pulse tube hot end heat exchanger.

The invention adopts the bellows DC blocking structure, which not only ensures the advantages of reducing the loss of the regenerator through the second intake air through the split flow, but also has the ability to adjust the phase relationship between the pressure wave and the velocity wave of the alternating flow of the working medium in the pulse tube and the pulse control. The strengthening effect of the pressure amplitude in the tube also cuts off the direct current flow circulating in the regenerator, the pulse tube and the second intake circuit, thereby eliminating the negative impact of the direct current on the refrigeration temperature and cooling capacity, and solving the problem of the traditional two-way intake pulse Operational stability problems due to direct flow in tube refrigerators.

In addition, the present invention uses a capillary instead of a needle valve as the second air intake structure, which avoids the inconvenience caused to users by adjusting the opening of the needle valve.

Description of drawings

The accompanying drawing is a structural schematic diagram of a two-way intake pulse tube refrigerator with a bellows direct current blocking structure.

Detailed ways

As shown in the attached figure, the two-way inlet pulse tube refrigerator with bellows DC blocking structure includes a compressor 1, a heat exchanger 2 at the hot end of a regenerator, a regenerator 3, a cold head 4, The pulse tube 5, the heat exchanger 6 at the hot end of the pulse tube, the small hole valve 7, and the gas storehouse 8 are provided with a bellows DC blocking structure 9 at the hot end of the pulse tube 5. A capillary 10 is provided between the hot ends of 5 .

The bellows DC blocking structure 9 is a section of bellows with one end closed, located in the vessel, arranged coaxially with the vessel, its open end close to the heat exchanger at the hot end of the vessel, and welded to the inner wall of the vessel, The inner cavity of the bellows communicates with the heat exchanger at the hot end of the pulse tube.

When the two-way inlet pulse tube refrigerator with bellows DC blocking structure is running, the pressure wave generated by the compressor is used as the driving source to realize the cooling effect during the reciprocating charging and discharging process. Specifically, during the charging process, the high-pressure gas from the compressor is diverted at the inlet of the regenerator, and part of it flows through the heat exchanger at the hot end of the regenerator and the regenerator for pre-cooling, and then enters the pulse tube through the cold head The cold end, the other part enters the inner cavity of the bellows through the second air intake of the capillary tube and the heat exchanger at the hot end of the pulse tube (part of the working fluid flows into the gas storage through the small hole valve), and the closed end of the bellows moves toward the cold end of the pulse tube. The working medium in the pulse tube is compressed, and the heat exchanger at the hot end of the pulse tube takes the compressed heat out of the system. During the deflation process, the inlet of the regenerator is at low pressure, the working medium in the pulse tube expands and cools down, and part of the working medium at the cold end of the pulse tube flows from the cold end of the regenerator to the hot end after transferring the cold energy to the cold head. Cool the stuffing in the regenerator, store cold energy for the next charging process, and finally return to the compressor; while the closed end of the bellows in the pulse tube moves toward the hot end of the pulse tube, pushing the working fluid in the bellows to exchange heat through the hot end of the pulse tube The second intake air of the device and the capillary tube returns to the compressor (at this time, part of the working fluid in the gas storage also returns to the compressor through the second intake air of the capillary tube). Repeating this cycle, the temperature of the cold end gradually decreases until it reaches an equilibrium state.

Because the second intake air bypasses part of the working fluid flowing through the regenerator, the flow loss of the regenerator is reduced and the efficiency of the regenerator is improved. Moreover, according to the phase modulation theory of enthalpy flow, the theoretical cooling capacity of a pulse tube refrigerator is equal to the enthalpy flow flowing through the pulse tube, and when the pressure wave in the pulse tube is in phase with the velocity wave, the enthalpy flow in the pulse tube is the largest. In the operation mode of the small hole and the phase modulation structure of the gas reservoir, the pressure wave in the pulse tube always lags behind the mass wave, and the mass flow introduced to the hot end of the pulse tube through the second gas inlet can promote the pressure at the cold end of the pulse tube. The waves are in phase with the velocity waves, and even the pressure waves lead the velocity waves, thus providing the pressure wave and velocity wave phase relationships required for efficient pulse tube cooling processes. At the same time, the mass flow introduced to the hot end of the pulse tube through the second intake air can also strengthen the compression and expansion process of the working medium in the pulse tube and improve its refrigeration performance. In the present invention, a section of bellows with one end closed is installed at the hot end of the vessel, and the closed end of the bellows moves back and forth under the action of the pressure difference on both sides to realize the transmission of pressure waves and velocity waves, and at the same time, the inner space of the vessel Divided into two parts, blocking the direct flow of Gedeon forming a loop along the regenerator, pulse tube and second intake pipe, can realize long-term high-efficiency and stable operation of the pulse tube refrigerator. It must be noted that the size of the bellows is a key parameter to ensure the normal operation of the refrigerator. In the design, it is necessary to determine the scavenging volume of the closed end of the bellows according to the amount of inflation and deflation that enters the hot end of the pulse tube through the second air intake. Under the premise of ensuring that the bellows does not rub against the inner wall of the pulse tube during the reciprocating expansion and contraction process, try to use a larger diameter Bellows, in order to shorten the length of the bellows and reduce the stroke of its closed end, while ensuring that the bellows work in a temperature zone near room temperature. This can not only ensure the normal operation of the refrigerator, but also help to prolong the life of the bellows.

In the present invention, the flow resistance characteristic of the capillary used as the second air inlet is optimized through experiments, and its length and diameter are determined, so that the user does not need to make any adjustments to the second air inlet.

Claims (2)

1. dual-way air-intake vascular refrigeator with corrugated pipe direct-current blocking-up structure, it comprises compressor (1), regenerator hot end heat exchanger (2), regenerator (3), cold head (4), vascular (5), vascular hot-side heat exchanger (6), little ports valve (7), the air reservoir (8) that is connected successively, it is characterized in that, be provided with corrugated pipe direct-current blocking-up structure (9) in the hot junction of vascular (5), between the hot junction of regenerator (3) air inlet and vascular (5), be provided with capillary (10).

2. a kind of dual-way air-intake vascular refrigeator according to claim 1 with corrugated pipe direct-current blocking-up structure, it is characterized in that, described corrugated pipe direct-current blocking-up structure (9) is the bellows of one section one end sealing, be positioned at vascular, be coaxial arrangement with vascular, its openend is near vascular hot-side heat exchanger, and with the welding of vascular inwall, the bellows inner chamber is communicated with vascular hot-side heat exchanger.

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