Built-in heat recovery system

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By building a heat recovery system into the air compressor, using a temperature control valve to adjust the lubricating oil cooling path, and combining a heat recovery heat exchanger and an oil cooler, the problems of large footprint and complex modification of the air compressor's external heat recovery device are solved, achieving efficient heat recovery and simplified modification.

CN223398882UActive Publication Date: 2025-09-30SUZHOU SULLAIR GAS EQUIP

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Patent Information

Application Number: CN202422790974.6
Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner
Filing Date: 2024-11-15
Publication Date: 2025-09-30
Estimated Expiration: 2034-11-15

AI Technical Summary

Technical Problem

The existing heat recovery device installed outside the air compressor occupies a large area, is complex to transform and requires high investment, and the existing air compressor wastes heat energy seriously.

Method used

A heat recovery system is built into the compressor main unit, which automatically adjusts the lubricating oil cooling path through a temperature control valve and combines a heat recovery heat exchanger with an oil cooler to achieve cooling and heat recovery of the lubricating oil.

Benefits of technology

It achieves efficient heat recovery, simplifies the transformation process, reduces transformation costs, and ensures the normal operation of the unit under different operating conditions.

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Patent Text Reader

Abstract

The embodiment of the utility model provides a built-in heat recovery system which comprises a compressor main machine, an oil-gas mixture outlet of the compressor main machine communicates with a gas inlet of an oil-gas separator, a gas outlet of the oil-gas separator communicates with an external gas using end, and a bottom oil outlet of the oil-gas separator communicates with an oil inlet of the compressor main machine through an oil return pipeline; a first temperature control valve, a heat recovery heat exchanger, a second temperature control valve and an oil cooler are arranged on the oil return pipeline, a water outlet of the heat recovery heat exchanger is communicated to an external heat utilization end, and heat in the lubricating oil can be recycled while the lubricating oil is cooled; during transformation, only one heat recovery heat exchanger and a corresponding temperature control valve need to be additionally arranged on an original oil return pipeline, the pipeline is simple, the occupied area is small, and the investment cost is low; and no matter whether a user uses heat recovery or not, normal operation of the compressor unit is not affected.

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Description

Technical Field

[0001] The utility model relates to the technical field of air compressors, in particular to a built-in heat recovery system. Background Art

[0002] The working process of the current screw air compressor is as follows: after the air passes through the intake air filter to filter out dust and other impurities in the atmosphere, it enters the compressor host through the intake valve. During the compression process, it mixes with the injected cooling lubricating oil to form an oil-gas mixture. The compressed oil-gas mixture is discharged into the oil-gas separator, and the oil-gas separator separates the high-temperature and high-pressure lubricating oil and compressed air. Due to the operating temperature requirements of the machine, these high-temperature and high-pressure lubricating oil and compressed air must be sent to their respective cooling systems for cooling. The compressed air is cooled by the aftercooler and then sent to the gas end, while the high-temperature lubricating oil is cooled by the oil cooler and then sent back to the compressor host to enter the next cycle.

[0003] Existing air compressors typically have an oil cooler installed inside the unit to cool the lubricating oil. The heat generated during the heat exchange process is directly discharged into the atmosphere, wasting a significant amount of heat energy. With increasingly stringent national energy efficiency requirements, customers are increasingly demanding heat recovery from air compressors. Typically, companies choose to install a heat recovery device external to the air compressor, independent of the compressor unit. This requires significant floor space and extensive modifications to the existing air compressor, resulting in complex piping and high investment. Utility Model Content

[0004] In view of this, an embodiment of the present invention provides a built-in heat recovery system to solve the technical problems that setting up an independent heat recovery device outside the air compressor occupies a large area and has complex pipelines after modification, resulting in large modification investment.

[0005] The embodiment of the present utility model provides a built-in heat recovery system, including a compressor main unit, the oil-gas mixture outlet of the compressor main unit is connected to the air inlet of an oil-gas separator, the air outlet of the oil-gas separator is connected to the external gas end, and the bottom oil outlet of the oil-gas separator is connected to the oil inlet of the compressor main unit through an oil return pipeline; a first temperature control valve, a heat recovery heat exchanger, a second temperature control valve and an oil cooler are provided on the oil return pipeline, the first temperature control valve and the second temperature control valve are both two-position three-way solenoid valves with one inlet and two outlets, a lubricating oil passage and a cooling medium passage are both provided in the heat recovery heat exchanger and the oil cooler, the lubricating oil passage is provided with an oil inlet and an oil outlet, and the cooling medium passage is provided with a water inlet and a water outlet;

[0006] The inlet of the first temperature-controlled valve is connected to the oil-gas separator, one of the outlets of the first temperature-controlled valve is connected to the inlet of the second temperature-controlled valve, and the other outlet of the first temperature-controlled valve is connected to the oil inlet of the heat recovery heat exchanger; the oil outlet of the heat recovery heat exchanger is connected between the first temperature-controlled valve and the second temperature-controlled valve, and the water outlet of the heat recovery heat exchanger is connected to the external heat-consuming end through the water outlet pipeline; one of the outlets of the second temperature-controlled valve is connected to the compressor main unit, and the other outlet of the second temperature-controlled valve is connected to the oil inlet of the oil cooler, and the oil outlet of the oil cooler is connected between the second temperature-controlled valve and the compressor main unit;

[0007] When the temperature of the lubricating oil flowing through the first temperature control valve is lower than its preset working temperature, the first temperature control valve is connected to the second temperature control valve; when the temperature of the lubricating oil flowing through the first temperature control valve is higher than its preset working temperature, the first temperature control valve is connected to the heat recovery heat exchanger;

[0008] When the temperature of the lubricating oil flowing through the second temperature control valve is lower than its preset working temperature, the second temperature control valve is connected to the compressor host; when the temperature of the lubricating oil flowing through the second temperature control valve is higher than its preset working temperature, the second temperature control valve is connected to the oil cooler.

[0009] Optionally, the operating temperature of the first temperature control valve is lower than the operating temperature of the second temperature control valve.

[0010] Optionally, a stop valve is provided on the water outlet pipe of the heat recovery heat exchanger.

[0011] Optionally, the heat recovery heat exchanger is a plate heat exchanger.

[0012] Optionally, an oil filter is provided between the second temperature control valve and the compressor main unit, and the oil outlet of the oil cooler is connected between the second temperature control valve and the oil filter.

[0013] Optionally, an aftercooler is provided between the oil-gas separator and the external air end, and a compressed air passage and a cooling water passage are provided in the aftercooler; the compressed air passage is provided with an air inlet connected to the oil-gas separator and an air outlet connected to the external air end; the cooling water passage is provided with a water inlet and a water outlet, the water inlet of the cooling water passage is connected to the external cooling water circulation pipeline, the water outlet of the cooling water passage is connected to the water inlet of the oil cooler, and the water outlet of the oil cooler is connected to the external cooling water circulation pipeline.

[0014] The embodiments of the present invention have the following beneficial effects:

[0015] 1. A heat recovery heat exchanger is added between the oil-gas separator and the oil cooler, and the cooling path of the lubricating oil is automatically adjusted by the first and second temperature control valves. The heat in the lubricating oil can be recovered and utilized while cooling the lubricating oil. The heat recovery efficiency is high, and after the heat is recovered, the unit will not operate in a high-temperature environment, and the performance of the unit can be better guaranteed. In addition, during the transformation, only a heat recovery heat exchanger and a corresponding temperature control valve need to be added to the original oil return pipeline. The pipeline is simple, the floor space is small, and the investment cost is low.

[0016] 2. The operating temperature of the first temperature control valve is lower than that of the second temperature control valve. When the user uses the heat recovery heat exchanger to cool the lubricating oil and recover heat, the cooled lubricating oil can be directly returned to the compressor host without passing through the oil cooler. When the user chooses not to use heat recovery, the cooling medium in the heat recovery heat exchanger does not participate in heat exchange. The heat recovery heat exchanger can be used as a normal lubricating oil passage, and the oil cooler cools the lubricating oil. Whether the user uses heat recovery or not, it will not affect the normal operation of the compressor unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 This is a system flow chart of an embodiment of the present utility model;

[0019] The numbers in the figure represent:

[0020] 1. Compressor main unit; 2. Oil-gas separator; 3. First temperature control valve; 4. Heat recovery heat exchanger; 5. Second temperature control valve; 6. Oil cooler; 7. Oil filter; 8. Aftercooler. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0022] like Figure 1As shown, an embodiment of the present invention provides a built-in heat recovery system, including a compressor main unit 1, the oil-gas mixture outlet of the compressor main unit 1 is connected to the air inlet of the oil-gas separator 2, and the air outlet of the oil-gas separator 2 is connected to the external gas end to transport the separated compressed gas to the external gas end; the bottom oil outlet of the oil-gas separator 2 is connected to the oil inlet of the compressor main unit 1 through the return oil pipeline to send the separated lubricating oil back to the compressor main unit 1 for recycling.

[0023] The return oil pipeline is equipped with a first temperature control valve 3, a heat recovery heat exchanger 4, a second temperature control valve 5, and an oil cooler 6. The first temperature control valve 3 and the second temperature control valve 5 are both two-position three-way solenoid valves with one inlet and two outlets. The heat recovery heat exchanger 4 and the oil cooler 6 are both equipped with a lubricating oil passage and a cooling medium passage for heat exchange with the lubricating oil passage. The lubricating oil passage has an oil inlet and an oil outlet, and the cooling medium passage has a water inlet and a water outlet.

[0024] The inlet of the first thermostatic valve 3 is connected to the oil-gas separator 2, one of its outlets is connected to the inlet of the second thermostatic valve 5, and the other outlet of the first thermostatic valve 3 is connected to the oil inlet of the heat recovery heat exchanger 4. The oil outlet of the heat recovery heat exchanger 4 is connected between the first and second thermostatic valves 3 and 5. The water inlet of the heat recovery heat exchanger 4 is connected to an external cooling medium pipeline, and the water outlet is connected to an external heat-using end through an outlet pipeline, allowing the user to recover the heat in the lubricating oil. Furthermore, a shut-off valve can be installed on the outlet pipeline of the heat recovery heat exchanger 4 to allow the user to select whether to use heat recovery. The heat recovery heat exchanger 4 preferably uses a plate heat exchanger, which has high heat exchange efficiency, low heat loss, compact structure, small footprint, and long service life.

[0025] One outlet of the second temperature control valve 5 is connected to the compressor main unit 1, and the other outlet of the second temperature control valve 5 is connected to the oil inlet of the oil cooler 6. The oil outlet of the oil cooler 6 is connected between the second temperature control valve 5 and the compressor main unit 1. Specifically, an oil filter 7 for removing impurities in the lubricating oil is provided between the second temperature control valve 5 and the compressor main unit 1, and the oil outlet of the oil cooler 6 is connected between the second temperature control valve 5 and the oil filter 7.

[0026] In addition, an aftercooler 8 is installed between the oil-gas separator 2 and the external air supply to cool the compressed air. The aftercooler 8 has a compressed air passageway and a cooling water passageway. The compressed air passageway has an air inlet connected to the oil-gas separator 2 and an air outlet connected to the external air supply. The cooling water passageway has a water inlet and a water outlet. The inlet of the cooling water passageway of the aftercooler 8 can be connected to the external cooling water circulation pipeline, and the water outlet can be connected to the water inlet of the oil cooler 6. The water outlet of the oil cooler 6 can be connected to the external cooling water circulation pipeline to recycle the cooling water.

[0027] When the temperature of the lubricating oil flowing through the first thermostatic valve 3 is lower than its preset operating temperature, the first thermostatic valve 3 communicates with the second thermostatic valve 5. The lubricating oil does not enter the heat recovery heat exchanger 4, but flows directly through the first thermostatic valve 3 into the second thermostatic valve 5. When the temperature of the lubricating oil flowing through the first thermostatic valve 3 is higher than its preset operating temperature, the first thermostatic valve 3 communicates with the heat recovery heat exchanger 4. The lubricating oil enters the heat recovery heat exchanger 4 through the first thermostatic valve 3, and then flows into the second thermostatic valve 5 after heat exchange and cooling in the heat recovery heat exchanger 4. When the temperature of the lubricating oil flowing through the second thermostatic valve 5 is lower than its preset operating temperature, the second thermostatic valve 5 communicates with the compressor main unit 1. The lubricating oil does not enter the oil cooler 6, but flows directly through the second thermostatic valve 5 into the compressor main unit 1. When the temperature of the lubricating oil flowing through the second thermostatic valve 5 is higher than its preset operating temperature, the second thermostatic valve 5 communicates with the oil cooler 6. The lubricating oil enters the oil cooler 6 through the second thermostatic valve 5, and then flows into the compressor main unit 1 after heat exchange and cooling in the oil cooler 6.

[0028] Furthermore, the operating temperature of the first temperature control valve 3 is lower than the operating temperature of the second temperature control valve 5. When the user uses the heat recovery heat exchanger 4 to cool and recover the lubricating oil, if the temperature of the cooled lubricating oil is lower than the preset operating temperature of the second temperature control valve 5, the lubricating oil can flow directly back to the compressor main unit 1 without passing through the oil cooler 6; if the temperature of the cooled lubricating oil is still higher than the preset operating temperature of the second temperature control valve 5, the lubricating oil will be cooled again by the oil cooler 6 before flowing into the compressor main unit 1, ensuring that the unit will not operate in a high-temperature environment. When the user closes the stop valve and chooses not to use heat recovery, the cooling medium in the heat recovery heat exchanger 4 does not participate in the heat exchange, and the heat recovery heat exchanger 4 can be used as a normal lubricating oil passage, with the lubricating oil only cooled by the oil cooler 6. In other words, regardless of whether the user uses heat recovery, the lubricating oil can be cooled and the normal operation of the compressor unit will not be affected.

[0029] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present invention. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A built-in heat recovery system comprising a compressor main unit, wherein the oil-gas mixture outlet of the compressor main unit is connected to the air inlet of an oil-gas separator, the air outlet of the oil-gas separator is connected to an external gas terminal, and the bottom oil outlet of the oil-gas separator is connected to the oil inlet of the compressor main unit via an oil return line; characterized in that: The oil return pipeline is provided with a first temperature control valve, a heat recovery heat exchanger, a second temperature control valve and an oil cooler. The first temperature control valve and the second temperature control valve are both two-position three-way solenoid valves with one inlet and two outlets. The heat recovery heat exchanger and the oil cooler are both provided with a lubricating oil passage and a cooling medium passage. The lubricating oil passage is provided with an oil inlet and an oil outlet, and the cooling medium passage is provided with a water inlet and a water outlet. The inlet of the first temperature-controlled valve is connected to the oil-gas separator, one of the outlets of the first temperature-controlled valve is connected to the inlet of the second temperature-controlled valve, and the other outlet of the first temperature-controlled valve is connected to the oil inlet of the heat recovery heat exchanger; the oil outlet of the heat recovery heat exchanger is connected between the first temperature-controlled valve and the second temperature-controlled valve, and the water outlet of the heat recovery heat exchanger is connected to the external heat-consuming end through the water outlet pipeline; one of the outlets of the second temperature-controlled valve is connected to the compressor main unit, and the other outlet of the second temperature-controlled valve is connected to the oil inlet of the oil cooler, and the oil outlet of the oil cooler is connected between the second temperature-controlled valve and the compressor main unit; When the temperature of the lubricating oil flowing through the first temperature control valve is lower than its preset working temperature, the first temperature control valve is connected to the second temperature control valve; when the temperature of the lubricating oil flowing through the first temperature control valve is higher than its preset working temperature, the first temperature control valve is connected to the heat recovery heat exchanger; When the temperature of the lubricating oil flowing through the second temperature control valve is lower than its preset working temperature, the second temperature control valve is connected to the compressor host; when the temperature of the lubricating oil flowing through the second temperature control valve is higher than its preset working temperature, the second temperature control valve is connected to the oil cooler.

2. The built-in heat recovery system according to claim 1, characterized in that: An operating temperature of the first temperature control valve is lower than an operating temperature of the second temperature control valve.

3. The built-in heat recovery system according to claim 2, characterized in that: A stop valve is provided on the water outlet pipe of the heat recovery heat exchanger.

4. The built-in heat recovery system according to claim 1, characterized in that: The heat recovery heat exchanger is a plate heat exchanger.

5. The built-in heat recovery system according to claim 1, characterized in that: An oil filter is provided between the second temperature control valve and the compressor main unit, and the oil outlet of the oil cooler is connected between the second temperature control valve and the oil filter.

6. The built-in heat recovery system according to claim 1, characterized in that: An aftercooler is provided between the oil-gas separator and the external air end, and a compressed air passage and a cooling water passage are provided in the aftercooler; the compressed air passage is provided with an air inlet connected to the oil-gas separator and an air outlet connected to the external air end; the cooling water passage is provided with a water inlet and a water outlet, the water inlet of the cooling water passage is connected to the external cooling water circulation pipeline, the water outlet of the cooling water passage is connected to the water inlet of the oil cooler, and the water outlet of the oil cooler is connected to the external cooling water circulation pipeline.