CN-115682487-B - Single-stage compression type liquid adding system and method for R744

CN115682487BCN 115682487 BCN115682487 BCN 115682487BCN-115682487-B

Abstract

The invention belongs to the technical field of R744 refrigeration, and particularly relates to a single-stage compression type liquid adding system and method for R744. The system comprises a pressurizing pipe section, a liquid storage tank and a filling pipe section which are sequentially arranged along an R744 travelling path, wherein the pressurizing pipe section comprises a gas storage tank, a first switching valve V1, a cooler, a compressor, a gas cooler and a second switching valve V2 which are sequentially arranged along a gas flow direction, the liquid filling system further comprises a return pipe section with a seventh switching valve V7, an inlet of the return pipe section is communicated with an inlet of a sixth switching valve V6, and an outlet of the return pipe section is communicated with the liquid storage tank. According to the invention, the R744 is pressurized and liquefied on line in a mode of coupling single-stage compression and multi-stage cooling, and the number of high-pressure gas pipelines is reduced by manually dividing the high-pressure gas phase region and the high-pressure liquid phase region, so that the input cost can be greatly reduced, and the risks of use and maintenance are remarkably reduced.

Inventors

ZHANG XIUPING
WANG RUJIN
CAI SONGSU
SHANG YUNHENG
ZHOU QUAN
HE JUNQIAN
DAI LIN

Assignees

合肥通用机械研究院有限公司
合肥通用环境控制技术有限责任公司

Dates

Publication Date: 20260512
Application Date: 20221104

Claims (7)

1. A method for a single stage compression filling system for R744, comprising a pressurized tube segment (20), a liquid reservoir (10) and a fill tube segment (30) directly connected to a device to be filled, arranged in sequence along a path of travel of R744, wherein: The pressurizing pipe section (20) comprises a gas storage tank (21), a first switch valve (V1), a cooler (22), a compressor (23), an air cooler (24) and a second switch valve (V2) which are sequentially arranged along the gas flow direction; The filling pipe section (30) comprises a third switch valve (V3), a parallel pipeline, a flow regulating valve (LV), a flowmeter (L1), a temperature and pressure measuring point and a sixth switch valve (V6) which are sequentially arranged along the liquid flow direction, wherein the parallel pipeline comprises a first parallel branch with a fifth switch valve (V5) and a second parallel branch with a fourth switch valve (V4) and a flow pump (31) which are sequentially arranged; the liquid adding system further comprises a return pipe section (40) with a seventh switch valve (V7), wherein the inlet of the return pipe section (40) is communicated with the inlet of the sixth switch valve (V6), and the outlet of the return pipe section (40) is communicated with the liquid storage tank (10); The liquid adding system further comprises an evacuating pipe section (50) with a vacuum pump (51), wherein an eighth switching valve (V8) and a ninth switching valve (V9) are respectively arranged at two ends of the evacuating pipe section (50), the end of the eighth switching valve (V8) is communicated with the outlet of the sixth switching valve (V6), and the end of the ninth switching valve (V9) is communicated with a section of filling pipe section between the third switching valve (V3) and the fourth switching valve (V4); the liquid adding system also comprises a heat exchanger (32), wherein the heat exchanger (32) is positioned on a section of filling pipe between the parallel pipeline and the flow regulating valve (LV); The method comprises the following steps: 1) And (3) pressurizing: starting a pressurizing pipe section (20), enabling a gaseous R744 in a gas storage tank (21) to enter a compressor (23) for pressurizing after passing through a first switch valve (V1) and a cooler (22), and enabling the compressor (23) to pressurize the R744 to an intermediate pressure; 2) And (3) vacuumizing: connecting the equipment to be filled to the outlet of a sixth switch valve (V6), opening an eighth switch valve (V8) and a vacuum pump (51), vacuumizing the equipment to be filled through an evacuating pipe section (50), closing the eighth switch valve (V8) and the vacuum pump (51) after the set vacuum requirement is met, and opening the sixth switch valve (V6) to complete the vacuumizing process, wherein the process is synchronous or sequential to the pressurizing process; 3) And (3) filling: a) Opening a filling pipe section (30), enabling a liquid 744 to sequentially pass through a third switch valve (V3), a fourth switch valve (V4), a flow pump (31) and a heat exchanger (32) and then reach a flow regulating valve (LV), regulating the flow of R744 by the flow regulating valve (LV), obtaining a flow value by a flowmeter (L1), obtaining a final temperature value and a final pressure value by a temperature and pressure measuring point, and entering filling equipment by a sixth switch valve (V6) to finish the filling process; b) When the final temperature value and the final pressure value obtained at the temperature and pressure measuring point do not meet the requirement of the equipment to be filled, closing a sixth switch valve (V6), opening a seventh switch valve (V7), returning the liquid 744 from the return pipe section (40) to the liquid storage tank (10) until the final temperature value and the final pressure value measured at the temperature and pressure measuring point meet the requirement of the equipment to be filled on the temperature and the pressure of R744, closing the seventh switch valve (V7), re-opening the sixth switch valve (V6), and then entering the next step; c) And (c) when the final pressure value measured by the temperature and pressure measuring point meets the requirement of the equipment to be filled on the temperature and the pressure of R744, closing the fourth switching valve (V4), opening the fifth switching valve (V5), and then performing the step a).
2. The method for the single-stage compression type liquid adding system of R744 according to claim 1, wherein the heat exchanger (32), the cooler (22) and the air cooler (24) are all communicated with the constant-temperature water tank (60) through cooling water pipes, a water pump is arranged on each cooling water pipe, an eleventh switch valve (V11) and a twelfth switch valve (V12) are correspondingly arranged on the cooling water pipes where the cooler (22) and the air cooler (24) are located, and a water temperature regulator (61) is arranged on the cooling water pipe where the heat exchanger (32) is located.
3. The method for a single stage compression charging system for R744 in accordance with claim 1, further comprising a cooling unit (70), wherein the cooling unit (70) is connected to a heat exchanging coil (11) of the liquid storage tank (10) through a pressure pump (71) and a tenth switching valve (V10).
4. A method for a single stage compression filling system for R744 as set forth in claim 3 wherein a liquid level gauge (12), a safety valve (13) and a camera (14) for video monitoring of the liquid in the tank are provided at the liquid reservoir (10).
5. A method for a single stage compression filling system for R744 as set forth in claim 1 wherein the flow pump (31) is a plunger pump.
6. A method for a single stage compression filling system for R744 as set forth in claim 1 wherein the return tube section (40) is further provided with a one-way valve (CV).
7. The method of claim 1 wherein each of the on-off valves is an automatic valve.

Description

Single-stage compression type liquid adding system and method for R744 Technical Field The invention belongs to the technical field of R744 refrigeration, and particularly relates to a single-stage compression type liquid adding system and method for R744. Background R744 is carbon dioxide, which is colorless, odorless, nontoxic, nonflammable, non-explosive, excellent in thermal properties, and is an environment-friendly substance inferior to water and air in industrial fields. R744 has the highest operating pressure compared to conventional refrigerants for the same application. For example, in an automotive air conditioning compressor system, if refrigerant R134a is used, the usual conditions are-1℃evaporation, 63℃condensation, a corresponding evaporation pressure of 2.82bar and a condensation pressure of 18.04bar, and if refrigerant R410a is used, the usual conditions are-1℃evaporation, 63℃condensation, a corresponding evaporation pressure of 7.73bar and a condensation pressure of 40.94bar. Also under normal conditions, refrigerant R744 was vaporized at-1℃and condensed at 63℃at an evaporation pressure of 33.9bar and a condensation pressure exceeding 120bar. It can be seen that the pressure-resistant requirement on all components and pipelines is very high when the filling device is applied to R744, and especially in the traditional filling device, a plurality of storage tanks are needed for sub-packaging and storing R744, each storage tank needs to bear extremely high working pressure, the filling pipe section directly communicated with each storage tank also always bears extremely high working pressure, and along with the position change of the filled device, the filling pipe section also needs to travel a longer distance, so that a high-pressure gas pipeline is quite long, and the input cost is quite high. At the same time, as these fill tube segments and the upper components will inevitably pass through some space in the field where the ambient temperature is high, the R744 within the tube will be passively heated, resulting in a further increase in pressure. For example, when an R744 filling device placed in a factory is placed, the local cylinder temperature of the air compressor may reach 100 ℃ when the filling pipe section passes by an operating air compressor, and when the filling pipe section is heated, the pressure in the filling pipe section with high pressure will be further increased, even to about 150bar, so that the risk of cracking or explosion of the filling pipe section is easy to occur, and the problem is to be solved. Disclosure of Invention One of the objectives of the present invention is to overcome the above-mentioned drawbacks of the prior art, and to provide a single-stage compression type liquid filling system for R744, which pressurizes and liquefies R744 online by means of coupling single-stage compression and multi-stage cooling, and reduces the high-pressure gas pipeline by means of artificially dividing the high-pressure gas-phase region and the high-pressure liquid-phase region, so that the input cost can be greatly reduced, and the risks of use and maintenance can be significantly reduced. It is another object of the present invention to provide a method for a single stage compression type liquid feeding system of R744, thereby further ensuring simplicity and efficiency of the operation flow. In order to achieve the above purpose, the present invention adopts the following technical scheme: a single-stage compression type liquid adding system for R744 is characterized by comprising a pressurizing pipe section, a liquid storage tank and a filling pipe section which are arranged along the R744 travelling path in sequence, wherein the filling pipe section is directly connected with equipment to be filled, and the single-stage compression type liquid adding system comprises the following components: the pressurizing pipe section comprises an air storage tank, a first switch valve V1, a cooler, a compressor, an air cooler and a second switch valve V2 which are sequentially arranged along the air flow direction; The filling pipe section comprises a third switch valve V3, a parallel pipeline, a flow regulating valve LV, a flowmeter L1, a temperature and pressure measuring point and a sixth switch valve V6 which are sequentially arranged along the liquid flow direction, wherein the parallel pipeline comprises a first parallel branch with a fifth switch valve V5 and a second parallel branch with a fourth switch valve V4 and a flow pump which are sequentially arranged; The liquid adding system further comprises a return pipe section with a seventh switch valve V7, wherein the inlet of the return pipe section is communicated with the inlet of the sixth switch valve V6, and the outlet of the return pipe section is communicated with the liquid storage tank. Preferably, the liquid adding system further comprises an evacuating pipe section with a vacuum pump, wherein the two ends of th