Oil-injected compressor unit

Abstract

An oil-injected compressor arrangement (1) comprising at least one oil-injected compressor element (2) with an inlet (5) for a gas to be compressed and an outlet (7) for the compressed gas, the outlet (7) being connected to an oil separator (9), the oil-injected compressor arrangement (1) further comprising an oil injection pipe (14) leading from the oil separator (9) to the oil-injected compressor element (2), an oil cooler (15) is integrated in the oil injection pipe (14), and an oil reservoir (17) is provided in the oil injection pipe (14) downstream of the inlet (16) of the oil cooler (15).

Description

[Technical field]

[0001] The present invention relates to an oil-injected compressor device.

[0002] More specifically, the present invention relates to an oil-injected compressor arrangement comprising at least one oil-injected compressor element having an inlet for a gas to be compressed and an outlet for the compressed gas, the outlet being connected to an oil separator, the oil-injected compressor arrangement further comprising an oil injection tube leading from the oil separator to the oil-injected compressor element, and an oil cooler integrated in the oil injection tube. [Background technology]

[0003] It is known that oil injected into a compressor unit is separated and stored in an oil separator.

[0004] This separated oil will be warm.

[0005] An oil injection line routes the oil along the cooler where it is cooled before being injected into the compressor elements.

[0006] Thus, such known installations have two major drawbacks.

[0007] The first drawback is that the oil is stored in an oil separator, which requires a large oil separator.

[0008] During start-up, oil from the oil separator circulates through the oil injection tube, the oil cooler and the oil-injected compressor elements. The oil separator is required to have a certain minimum volume since there must be enough oil to supply the entire system.

[0009] The oil separator is essentially a pressure vessel and is an expensive piece of equipment.

[0010] Additionally, the large size of the oil separator reduces the possibility of a compact system.

[0011] A further drawback is that the oil stored in the oil separator is warm or hot, as it comes from the compressor elements. The oil is cooled just before injection, but as a result it is stored at a high temperature.

[0012] This will affect the useful life of the oil.

[0013] The useful life of the oil is determined by its temperature: the hotter the oil is, or the longer it remains hot, the sooner the oil should be changed; the cooler the oil is, the longer its useful life will be.

[0014] This results in additional costs for oil changes, associated labor, and equipment downtime. Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention aims to provide a solution to at least one of the above and other disadvantages. [Means for solving the problem]

[0016] The object of the invention relates to an oil-injected compressor arrangement comprising at least one oil-injected compressor element with an inlet for the gas to be compressed and an outlet for the compressed gas, the outlet being connected to an oil separator, the oil-injected compressor arrangement further comprising an oil injection pipe leading from the oil separator to the oil-injected compressor element, an oil cooler is integrated in the oil injection pipe and an oil reservoir is provided in the oil injection pipe downstream of the inlet of the oil cooler.

[0017] The oil reservoir is a means capable of temporarily storing a predetermined amount of oil.

[0018] The advantage is that since a predetermined amount of oil is stored in the oil reservoir, less oil needs to be fed to the oil separator, making the oil separator smaller and less expensive.

[0019] Storing oil in the oil storage section allows greater freedom in designing the device and enables more efficient distributed layout, making the device more compact.

[0020] Another advantage is that the oil in the oil reservoir is cooled because the oil passes through an oil cooler before entering the oil reservoir.

[0021] As a result, the useful life of the oil is increased as compared to known oil injected compressor systems in which the oil is stored at elevated temperatures.

[0022] Yet another advantage is that the oil in the oil reservoir is pumped into the compressor unit more quickly during start-up as compared to the oil in the oil separator.

[0023] During start-up of known systems, all the oil is in the oil separator and must pass through the oil cooler before being injected.

[0024] In the device according to the invention, oil can be poured in immediately from an oil reservoir, the oil having already been cooled.

[0025] In particular, the bearings and other components of the equipment will receive oil more quickly for cooling, lubrication and / or sealing.

[0026] This has a beneficial effect on the useful life of these components and on the performance of the device.

[0027] The oil storage described above can be accomplished in a number of ways.

[0028] In a practical embodiment, the oil reservoir comprises: - an oil container integrated into the oil inlet pipe downstream of the oil cooler; a portion of the oil injection tube downstream of the oil cooler having a larger diameter than the remainder of the oil injection tube; Includes one or more of the following.

[0029] The advantage of the oil container is that it is integrated into the oil inlet tube and therefore does not become a pressure container, as opposed to an oil separator which is connected to the outlet of the compressor element and therefore also receives compressed gas.

[0030] The advantage of the large diameter section of the oil injection tube is that a volume for storing oil is thus created without increasing the distance the oil must travel.

[0031] Another advantage is that the device is compact since there is no need to prepare a separate oil container.

[0032] Another practical embodiment is to place the oil reservoir downstream of the inlet of the oil cooler and include the oil reservoir in the oil cooler.

[0033] In this case, the oil cooler functions as an oil container for storing oil.

[0034] In this case, the oil cooler is preferably equipped with a valve to prevent return of oil from the oil reservoir when the device is shut down.

[0035] In another embodiment, the compressor arrangement includes a motor for driving the compressor element, the oil reservoir being integrated into the motor shell.

[0036] In such an embodiment, the motor shell acts as the oil reservoir, eliminating the need for a separate oil container and resulting in a very compact device.

[0037] During start-up, oil may also be injected directly into the motor and compressor elements.

[0038] With the insight to better illustrate the characteristics of the present invention, some preferred embodiments of an oil-injected compressor arrangement according to the invention will now be described, by way of non-limiting examples, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0039] [Figure 1] 1 illustrates diagrammatically an oil-injected compressor arrangement according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] The oil-injected compressor arrangement 1 shown diagrammatically in FIG.

[0041] For example, the compressor element 2 can be a screw compressor element, but other types of compressor elements 2 are not excluded.

[0042] Moreover, it is not excluded that the compressor arrangement 1 comprises two or more compressor elements 2.

[0043] The compressor element 2 is provided with a drive device 3. Figure 1 shows the drive device 3 diagrammatically in the form of a motor 4.

[0044] The compressor element 2 has an inlet 5 for the gas to be compressed.

[0045] In this case, an inlet filter 6 is connected to this inlet 5 in order to purify the drawn-in gas.

[0046] The compressor element 2 also has an outlet 7 for the compressed gas.

[0047] A discharge pipe 8 is connected to the outlet 7 for connecting the outlet 7 to an oil separator 9 .

[0048] In this case, an outlet pipe 10 is connected to the oil separator 9 for compressed gas, and a second oil separator 11 and an aftercooler 12 are incorporated in the outlet pipe 10.

[0049] In this case, the aftercooler 12 is air-cooled by a fan 13 .

[0050] The compressor arrangement 1 also includes an oil inlet pipe 14 leading from the oil separator 9 to the compressor element 2 .

[0051] An oil cooler 15 is built into this oil injection pipe 14.

[0052] In this case, the oil cooler 15 is an air-cooled type cooler, and the above-mentioned fan 13 also cools the oil cooler 15.

[0053] Instead of providing one common fan 13 for the aftercooler 12 and the oil cooler 15, it is not excluded to provide one common fan device or to provide separate fans or fan assemblies.

[0054] According to the invention, downstream of the inlet 16 of the oil cooler 15 an oil reservoir 17 is provided.

[0055] This oil reservoir 17 can be realised in various ways, as mentioned above.

[0056] In the example shown in FIG. 1, the oil reservoir 17 comprises an oil container 18 that is integrated into the oil inlet tube 14 downstream of the oil cooler.

[0057] Of course, the oil reservoir 17 could be provided in a different way, i.e. the portion of the oil injection tube 14 downstream of the oil cooler 15 has a larger diameter than the remaining portion of the oil injection tube 14; - to be incorporated in the oil cooler 15; - being incorporated into the outer shell structure 19 of the engine 4; It is not excluded that this could be achieved in the following way.

[0058] In the illustrated example, an oil filter 20 is provided in the oil inlet pipe 14 immediately upstream of the oil reservoir 17, i.e. the oil container 18.

[0059] It is not excluded that more than one oil filter 20 is provided.

[0060] Additionally, one or more of these oil filters 20 may be provided downstream of the oil reservoir 17 .

[0061] In this case, although not required by the invention, the oil cooler 15 and the oil reservoir 17 can be bypassed using a bypass line 21 .

[0062] This bypass line 21 extends from a point A in the oil inlet pipe 14 upstream of the oil cooler 15 to a point B in the oil inlet pipe 14 downstream of the oil reservoir 17 .

[0063] Control means 22 is also provided in the form of a three-way valve 23 so as to be able to control the amount of oil passing through the bypass line 21 .

[0064] Instead of the three-way valve 23, the control means 22 may also consist of a thermostat and / or a combination of one or more valves.

[0065] In FIG. 1, the control means 22 is provided in the oil injection pipe 14 downstream of the oil reservoir 17, i.e., at point B mentioned above, but it may also be provided upstream of the oil cooler 15, i.e., at point A mentioned above.

[0066] The operation of the compressor unit 1 is quite simple and is as follows.

[0067] During operation of the compressor unit 1, gas to be compressed is drawn in through inlet 5. The gas passes through inlet filter 6 to remove impurities.

[0068] In the compressor element 2 the gas is compressed.

[0069] The motor 4 will drive the compressor element 2 and oil will be injected into the compressor element 2 and the motor 4 .

[0070] The compressed gas and injected oil leave the compressor element 2 through an outlet 7 and pass through a discharge line 8 into an oil separator 9 .

[0071] During compression, the gas and oil will heat up.

[0072] In the oil separator 9, the compressed gas is separated from the oil, after which the gas passes through the outlet pipe 10 to the second oil separator 11, which further separates the final oil. In this case, the oil separated in the second oil separator 11 is injected into the compressor element 2.

[0073] The compressed gas then passes through an aftercooler 12 which cools the gas before it leaves the compressor unit 1 .

[0074] The oil separated in the oil separator 9 is transported by the pressure of the compressed gas in the oil separator 9 through the injection pipe 14 to the oil cooler 15 or is injected directly into the compressor element 2 through a bypass line 21 .

[0075] In the oil cooler 15 the oil is cooled and then enters the oil reservoir 17 .

[0076] This ensures that the oil first passes through the oil filter 20 and finally the cooled and purified oil enters the oil reservoir 17 .

[0077] The oil remains in the oil reservoir 17 until the control means 22 is opened to allow oil to be pumped from the oil reservoir 17 .

[0078] The control means 22 will decide how much still hot oil will be injected from the bypass line 21 and how much cooled oil will be injected from the oil reservoir 18 .

[0079] These control means 22 make it possible to control the temperature of the injected oil.

[0080] A control device or the like can be provided to manage these control means 22.

[0081] In the present invention, the oil separator 9 is smaller than known devices, so less oil is stored and most of the oil is cooled and stored in the oil container 18.

[0082] Additionally, upon start-up, oil from the oil reservoir 18 can be immediately pumped into the bearings and other components of the compressor element 2 .

[0083] The invention is not limited to the embodiment described by way of example and shown in the drawings, and the oil-injected compressor device according to the invention can be realized in any shape and size without departing from the scope of the invention. [Explanation of symbols]

[0084] 1. Oil-injected compressor unit 2. Oil-injected compressor elements 5 Entrance 7 Exit 9 Oil Separator 14 Oil injection pipe 15 Oil cooler 17 Oil Reservoir

Claims

1. An oil-injected compressor arrangement (1) comprising at least one oil-injected compressor element (2) with an inlet (5) for a gas to be compressed and an outlet (7) for the compressed gas, said outlet (7) being connected to an oil separator (9), said oil-injected compressor arrangement (1) further comprising an oil injection pipe (14) leading from said oil separator (9) to said oil-injected compressor element (2), an oil cooler (15) being integrated into said oil injection pipe (14), 10. An oil-injected compressor arrangement, characterized in that an oil reservoir (17) is provided in the oil injection pipe (14) downstream of the inlet (16) of the oil cooler (15).

2. The oil reservoir (17) is an oil container (18) integrated into the oil inlet pipe (14) downstream of the oil cooler (15); - a part of the oil injection pipe (14) downstream of the oil cooler (15) which has a larger diameter than the remaining part of the oil injection pipe (14); 2. The oil injected compressor arrangement of claim 1, comprising one or more of:

3. 2. The oil-injected compressor arrangement of claim 1, wherein the oil reservoir (17) is located downstream of the inlet (16) of the oil cooler (15), and the oil reservoir (17) is integrated into the oil cooler (15).

4. 2. The oil-injected compressor arrangement of claim 1, wherein the compressor arrangement (2) comprises a motor (4) for driving the compressor element (2), and the oil reservoir (17) is integrated into an outer shell structure (19) of the motor (4).

5. 5. An oil-injected compressor arrangement according to claim 1, further comprising a bypass line extending from a point A of the oil injection pipe upstream of the oil cooler to a point B of the oil injection pipe downstream of the reservoir, such that oil can bypass the oil cooler and the reservoir through the bypass line, and control means are provided for controlling the amount of oil passing through the bypass line.

6. 6. The oil injected compressor arrangement of claim 5, wherein the control means (22) is a three-way valve (23), a thermostat and / or a combination of one or more valves.

7. 7. An oil-injected compressor arrangement according to claim 5 or 6, wherein the control means (22) upstream of the oil cooler (15) or downstream of the oil reservoir (17) is integrated in the oil injection pipe (14).

8. 8. An oil injected compressor arrangement according to any one of claims 1 to 7, wherein an outlet pipe (10) is connected to the oil separator (9) and an aftercooler (12) is integrated in the outlet pipe (10).

9. 9. An oil injected compressor arrangement according to claim 8, wherein a second oil separator (11) is integrated in the outlet pipe (10).

10. 10. The oil-injected compressor arrangement according to claim 8 or 9, wherein the aftercooler (12) and the oil cooler (15) are air-cooled coolers and one common fan (13) or fan group is provided for the aftercooler (12) and the oil cooler (15).

11. 11. An oil-injected compressor arrangement according to any of the preceding claims, wherein one or more oil filters (20) are incorporated in the oil injection pipe (14) immediately upstream or downstream of the oil reservoir (17).

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