Multi-stage oil-free compressor system

Abstract

The multi-stage oil-free compressor system comprises a plurality of compression main machines which are connected in series stage by stage, an exhaust port of the upper-stage compression main machine communicates with an air inlet of the lower-stage compression main machine through an exhaust pipeline, and an exhaust port of the last-stage compression main machine communicates with an air using end through an exhaust pipeline; the exhaust pipeline of the last-stage compression main engine is communicated with the exhaust pipeline of the first-stage compression main engine through an air return branch pipe, and a regulating valve is mounted on the air return branch pipe; high-pressure gas exhausted by the last-stage compression main engine is led to the exhaust pipeline of the first-stage compression main engine, and the first-stage exhaust pressure is increased through the backflow high-pressure gas, so that the second-stage compression ratio is reduced, the exhaust temperature is reduced, and the compressor system can still operate under the rated exhaust pressure in high-altitude areas.

Description

Technical Field

[0001] The utility model relates to the technical field of compressors, in particular to a multi-stage oil-free compressor system. Background Art

[0002] Atmospheric pressure will gradually decrease with the increase of altitude. When the compressor reaches the rated exhaust pressure, the pressure ratio of the compressor will also increase. Unlike oil compressors, there is no lubricating oil as a cooling medium in the compression chamber of oil-free compressors. Therefore, according to the formula As the compression ratio increases, the exhaust temperature of the main engine also rises. For multi-stage oil-free compressor systems with more than two stages, the volumetric flow rate of each stage's compression main engine is fixed, so the pressure ratio between stages is less affected by the increase in altitude. This results in an increase in the pressure ratio of the final stage's compression main engine, and a subsequent increase in exhaust temperature. The main engine's maximum exhaust temperature is determined by factors such as the main engine's rotor design clearance and rotor coating performance, and cannot be adjusted based on changes in altitude. Therefore, when a multi-stage oil-free compressor system is used in high-altitude areas, it is often necessary to reduce the exhaust pressure to lower the compression ratio due to the main engine's exhaust temperature, thus failing to achieve the machine's rated exhaust. Utility Model Content

[0003] In view of this, an embodiment of the present invention provides a multi-stage oil-free compressor system to solve the technical problem that the existing multi-stage oil-free compressor system is difficult to achieve rated exhaust in high-altitude areas.

[0004] An embodiment of the present invention provides a multi-stage oil-free compressor system, comprising a plurality of compression main units connected in series step by step, wherein the exhaust port of the upper-stage compression main unit is connected to the air inlet of the lower-stage compression main unit through an exhaust pipeline, and the exhaust port of the last-stage compression main unit is connected to the gas-using end through an exhaust pipeline; wherein the exhaust pipeline of the last-stage compression main unit is connected to the exhaust pipeline of the first-stage compression main unit through a return air branch pipe, and a regulating valve is installed on the return air branch pipe.

[0005] Optionally, the number of the compression main units is greater than or equal to three, wherein the exhaust pipeline of the intermediate compression main unit is also connected to the exhaust pipeline of the first-stage compression main unit through a return air branch pipe, and the regulating valve is installed on each of the return air branch pipes.

[0006] Optionally, a cooler is provided on the exhaust pipeline of each stage of the compression main unit, and both ends of the return air branch pipe are respectively connected to the air inlet side of the corresponding cooler.

[0007] Optionally, the exhaust port of each stage of the compression main unit is installed with a temperature sensor and a pressure sensor.

[0008] Optionally, the regulating valve is a manual valve.

[0009] Optionally, it further includes a controller; the regulating valve is an automatic valve, and the regulating valve, the temperature sensor, and the pressure sensor are all electrically connected to the controller.

[0010] The embodiment of the present utility model has the following beneficial effects: The exhaust pipe of the final-stage compression main unit is connected to the exhaust pipe of the first-stage compression main unit through a return air branch pipe, and a regulating valve is installed on the return air branch pipe to introduce the high-pressure gas discharged from the final-stage compression main unit to the exhaust pipe of the first-stage compression main unit. By the reflux of the high-pressure gas, the first-stage exhaust pressure is increased, thereby reducing the second-stage compression ratio and the exhaust temperature, so that the compressor system can still operate at the rated exhaust pressure in high-altitude areas. Description of the Drawings

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present utility model. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0012] Figure 1 It is a schematic structural diagram of manual adjustment of the embodiment of the present utility model;

[0013] Figure 2 It is a schematic structural diagram of automatic adjustment of the embodiment of the present utility model;

[0014] The numbers in the figure represent:

[0015] 1. First-stage compression main unit; 2. Final-stage compression main unit; 3. Return air branch pipe; 4. Regulating valve; 5. Cooler; 6. Temperature sensor; 7. Pressure sensor; 8. Controller. Detailed Embodiments

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present utility model. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present utility model, and are not used to limit the present utility model. In the description of the present utility model, the meaning of "multiple" is two or more, unless otherwise specifically defined.

[0017] Please refer to Figure 1 、 Figure 2As shown in the figure, an embodiment of the present utility model provides a multi-stage oil-free compressor system, which includes multiple compression main engines connected in series step by step. The exhaust port of the upper-stage compression main engine is connected to the intake port of the lower-stage compression main engine through an exhaust pipe, and the exhaust port of the last-stage compression main engine 2 is connected to the gas-using end through an exhaust pipe. Among them, the exhaust pipe of the last-stage compression main engine 2 is connected to the exhaust pipe of the first-stage compression main engine 1 through a return air branch pipe 3, so that the high-pressure gas discharged from the last-stage compression main engine 2 can be led to the exhaust pipe of the first-stage compression main engine 1 through this return air branch pipe 3; a regulating valve 4 is installed on the return air branch pipe 3 for regulating the return air volume of the return air branch pipe 3.

[0018] According to the actual situation, when the altitude rises, the atmospheric pressure drops and the average ambient temperature also drops accordingly. As described in the background technology, for a multi-stage oil-free compressor system, the pressure ratio between stages changes little, so the exhaust temperature between stages will decrease due to the decrease in the intake temperature. In view of this characteristic, the embodiment of the present utility model leads the high-pressure gas discharged from the last-stage compression main engine 2 to the exhaust pipe of the first-stage compression main engine 1 through the return air branch pipe 3 to increase the inter-stage pressure through the refluxed high-pressure gas.

[0019] Taking a two-stage oil-free compressor system as an example (the same applies to other multi-stage oil-free compressor systems with three or more stages by analogy), the second-stage compression main engine of the two-stage oil-free compressor system is the last-stage compression main engine 2. The exhaust port of the first-stage compression main engine 1 is connected to the intake port of the second-stage compression main engine through an exhaust pipe, and the exhaust port of the second-stage compression main engine is connected to the gas-using end through an exhaust pipe. At the same time, the exhaust pipe of the second-stage compression main engine is connected to the exhaust pipe of the first-stage compression main engine 1 through the return air branch pipe 3 to lead part of the high-pressure gas discharged from the second-stage compression main engine to the exhaust pipe of the first-stage compression main engine 1, so that the exhaust pressure of the first-stage compression main engine 1 increases and the compression ratio of the first-stage compression main engine 1 increases. However, since the intake temperature of the first-stage compression main engine 1 is relatively low, the first-stage exhaust temperature can still remain within the normal operating range after the first-stage compression ratio increases. And the compression ratio of the second-stage compression main engine will decrease due to the increase in the first-stage exhaust pressure (i.e., the intake pressure of the second-stage compression main engine), so that the exhaust temperature of the second-stage compression main engine decreases, and the second-stage compression main engine does not need to be limited by the exhaust temperature and can still operate at the rated exhaust pressure.

[0020] Further, for a multi-stage oil-free compressor system with three or more stages (i.e., the number of compression main engines is greater than or equal to three), to meet the requirement of the gas return volume, the exhaust pipe of the intermediate-stage compression main engine can also be connected to the exhaust pipe of the first-stage compression main engine 1 through the gas return branch pipe 3, and a regulating valve 4 is installed on each gas return branch pipe 3. Specifically, a cooler 5 is provided on the exhaust pipe of each stage of the compression main engine, and both ends of the gas return branch pipe 3 are respectively connected to the intake side of the corresponding cooler 5. When the compressor system operates normally in a low-altitude environment, the regulating valves 4 on each gas return branch pipe 3 can be closed; when the compressor system operates in a high-altitude environment, to ensure its normal operation under the rated exhaust pressure, the regulating valve 4 on the gas return branch pipe 3 between the last-stage compression main engine 2 and the first-stage compression main engine 1 can be opened and adjusted, and the high-pressure gas discharged from the last-stage compression main engine 2 is used to adjust the inter-stage pressure; as the altitude gradually increases, the regulating valves 4 on multiple gas return branch pipes 3 can be opened and adjusted simultaneously, so that the gas return volume meets the requirement for the normal operation of the compressor system at the current altitude.

[0021] Further, a temperature sensor 6 and a pressure sensor 7 are installed at the exhaust port of each stage of the compression main engine, which are used to monitor the exhaust temperature and exhaust pressure of the corresponding compression main engine in real time, so as to facilitate the adjustment of the gas return volume of the gas return branch pipe 3.

[0022] The regulating valve 4 can be a manual valve or an electric valve. As Figure 1 shown, when the regulating valve 4 is a manual valve, the staff can manually adjust the opening degree of each regulating valve 4 according to the exhaust temperature and exhaust pressure of each stage of the compression main engine to ensure the normal operation of the compressor system under the rated exhaust pressure. As Figure 2 shown, when the regulating valve 4 is an automatic valve, the regulating valve 4, the temperature sensor 6 and the pressure sensor 7 can be electrically connected to the controller 8, and the controller 8 automatically adjusts the opening degree of each regulating valve 4 according to the real-time exhaust temperature and exhaust pressure of each stage of the compression main engine to ensure the normal operation of the compressor system under the rated exhaust pressure.

[0023] In this article, specific examples are used to elaborate on the principle and implementation mode of the present utility model. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present utility model; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present utility model.

Claims

1. A multi-stage oil-free compressor system, characterized in that: It includes multiple compression main engines connected in series step by step. The exhaust port of the upper-stage compression main engine is connected to the intake port of the lower-stage compression main engine through an exhaust pipe, and the exhaust port of the last-stage compression main engine is connected to the gas-using end through an exhaust pipe. Among them, the exhaust pipe of the last-stage compression main engine is connected to the exhaust pipe of the first-stage compression main engine through a return air branch pipe, and a regulating valve is installed on the return air branch pipe.

2. The multi-stage oil-free compressor system according to claim 1, wherein: The number of the compression main engines is greater than or equal to three. Among them, the exhaust pipe of the intermediate-stage compression main engine is also connected to the exhaust pipe of the first-stage compression main engine through a return air branch pipe, and the regulating valve is installed on each return air branch pipe.

3. The multi-stage oil-free compressor system according to claim 2, characterized in that: Coolers are arranged on the exhaust pipes of each stage of the compression main engine, and both ends of the return air branch pipe are respectively connected to the intake side of the corresponding cooler.

4. The multi-stage oil-free compressor system according to claim 3, wherein: Temperature sensors and pressure sensors are installed at the exhaust ports of each stage of the compression main engine.

5. The multi-stage oil-free compressor system according to claim 4, wherein: The regulating valve adopts a manual valve.

6. The multi-stage oil-free compressor system according to claim 4, wherein: It further includes a controller; the regulating valve adopts an automatic valve, and the regulating valve, the temperature sensor and the pressure sensor are all electrically connected to the controller.

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