JP2003185090A - Oil purifying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil purifying apparatus capable of eliminating air mixed into a return oil pump and implementing sufficient cleanliness with compact structure. <P>SOLUTION: Lubricating oil is fed by a suction pump 12 to a centrifugal separator 13 to be processed, is stored in a purified oil tank 15, is fed out by a discharge pump 17 and passes through a precision filter 18, and then is directly returned to an engine. The precision filter has pressure tightness for standing against back pressure generated by resistance of piping 19. A return valve 22 is disposed to a return pipe 22 connecting a intermediate portion between the discharge pump and the precision filer with the purified oil tank, the return valve is opened or closed according to the height of the oil level in the purified oil tank to keep the liquid level in the tank at a predetermined height. Since the precision filter is high in pressure tightness, there is no problem although the pressure of the lubricating oil is high when the lubricating oil is low in temperature and high in viscosity, and thereby the need for a heater is eliminated. Disadvantage by the back pressure of the filter is reduced and the lubricating oil can be directly returned to the engine or the like. Since the oil level in the tank is constant, the air is not sucked into the discharge pump, thereby preventing the air from being contained in the precision filter. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil cleaning device applied to a machine that circulates and uses some working oil. The present invention is effective for cleaning lubricating oil in an internal combustion engine such as a diesel engine.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram of an oil cleaning apparatus proposed by the applicant of the present application. The lubricating oil stored in the sump tank 1 of the internal combustion engine is sucked by the suction pump 2 and supplied to the centrifuge 4 via the electric heater 3 for reducing the viscosity of the lubricating oil. The lubricating oil from which carbon and the like have been separated by the centrifugal force is temporarily stored in the clean oil tank 5. The lubricating oil in the clean oil tank 5 is sucked up by the pump 6, supplied to the filter 8 through the filter heater 7 for reducing the viscosity of the lubricating oil, further increased in cleanliness, and again the clean oil tank 5 Returned to. It is sucked by a return oil pump 10 from a suction pipe 9 arranged slightly below the liquid surface of the clean oil tank 5 and returned to the sump tank 1.

FIG. 10 is a diagram showing the outlet temperature of the filter heater 7 and the pressure at the filter inlet of the filter 8 in this oil cleaning apparatus. As shown in this figure, the outlet temperature of the filter heater 7 is 60 to 80 ° C., and the pressure at the filter inlet of the filter 8 is about 0.05 MPa.

[0004]

As described above, in the conventional oil cleaning device, the cleaning oil tank 5 has the lubricating oil processed by the centrifugal separator 4 and the lubricating oil further cleaned by the filter 8. Since both of the oils are supplied and mixed with each other, there is a problem that the lubricating oil having insufficient cleanliness is returned to the sump tank 1 and carbon or the like is deposited on the bottom of the tank 1.

In order to avoid such a problem, the oil return pump 1
The lubricating oil suction port of 0 is arranged near the liquid surface so that the supernatant of the lubricating oil in the clean oil tank 5 can be sucked and the liquid level of the clean oil tank can be secured as described above. However, depending on the operating conditions, new problems may occur such that air may be mixed into the oil return pump 10.

Therefore, in order to solve all of these problems, it is sufficient to supply all the lubricating oil that has passed through the filter 8 to the sump tank 1. For this purpose, a large number of filters must be installed. You will need it. This is because the filter 8 used in the conventional oil cleaning device has a low pressure resistance and cannot apply a sufficient filtration pressure, so that the processing amount of the lubricating oil in each filter 8 is small.

If all of the lubricating oil that has passed through the filter 8 is directly returned to the sump tank 1, the lubricating oil coming out of the filter 8 has almost no pressure, so that the second lubricating oil tank Is separately provided, and the lubricating oil discharged from the filter 8 is temporarily stored in the second lubricating oil tank.
The lubricating oil tank must be returned to the sump tank 1 by the oil return pump 10 again. Therefore, the size of the oil cleaning device becomes large, which causes a problem that the installation area cannot be secured.

Therefore, the present invention provides an oil cleaning apparatus which has a compact structure and can return oil of sufficient cleanliness to the machine side without causing inconveniences such as air mixing in the oil return pump. It is intended to be provided.

[0009]

An oil cleaning device according to claim 1 is provided in a machine for circulating and using oil, and is used in the machine in an oil cleaning device for cleaning the oil. A suction pump (12) for pumping the discharged oil, a centrifuge (13) for removing insolubles from the oil pumped by the suction pump to obtain a first clean oil, and a centrifuge A clean oil tank (15) for storing the discharged first clean oil, a discharge pump (17) for sending the first clean oil from the clean oil tank, and a first clean oil supplied from the discharge pump. Connected to the machine via a pipe (19) so that the second clean oil can be directly returned to the machine.
A precision filter (18) having pressure resistance capable of withstanding a back pressure generated by the resistance of the pipe, and a return pipe (21) connecting between the discharge pump and the precision filter connected to each other and the clean oil tank. Provided in the return pipe, and is operated so that the first clean oil returns to the clean oil tank via the return pipe in accordance with the height of the liquid surface of the first clean oil in the clean oil tank. And a return valve (22).

An oil cleaning apparatus according to a second aspect is the oil cleaning apparatus according to the first aspect, wherein the cleaning oil tank (1
5) is provided with return valve operating means (ball tap 24) for changing the opening of the return valve (22) according to the height of the liquid surface of the first clean oil.

An oil purifying apparatus according to a third aspect is the oil purifying apparatus according to the first aspect, wherein the clean oil tank (1
5) The liquid level gauge (23) for detecting the height of the liquid level of the first clean oil in (5) is provided.

An oil purifying apparatus according to a fourth aspect is the oil purifying apparatus according to the first aspect, wherein the discharge pump (1
The suction port of the suction side pipe (discharge pipe 16) of 7) opens near the bottom of the clean oil tank (15), and the discharge port of the return pipe (21) is the first clean oil of the clean oil tank. It is characterized in that it is arranged below the liquid surface of.

The oil cleaning apparatus according to a fifth aspect is the oil cleaning apparatus according to the first aspect, wherein the return pipe (21) is provided.
The pressure detection means (28) provided between the branch of the precision filter (18) and the inlet of the precision filter (18), and a relief valve (bypass valve 27) connecting the inlet and the outlet of the precision filter. When the means detects an increase in pressure, the relief valve is opened so that the first clean oil sent from the discharge pump bypasses the precision filter.

An oil purifying apparatus according to a sixth aspect is the oil purifying apparatus according to the first aspect, wherein the return pipe (21) is provided.
In the above, the discharge valve (50) is provided upstream of the return valve (22).

An oil cleaning apparatus according to a seventh aspect of the present invention is an oil cleaning apparatus provided in a machine that circulates and uses oil to clean the oil, and pumps the oil used in the machine. A suction pump (12), a centrifuge (13) for removing insolubles from the oil pumped by the suction pump to obtain a first clean oil, and a first cleaning supplied from the centrifuge. Clean oil tank for storing oil (15)
A discharge pump (17) for sending a first clean oil from the clean oil tank, and a first pump supplied from the discharge pump.
Has the function of passing the second clean oil to the second clean oil,
A precision filter (1) connected to the machine through a pipe so that the second clean oil is directly returned to the machine and having pressure resistance capable of withstanding a back pressure generated by resistance of the pipe (1
8) and a return pipe (21) connecting between the discharge pump and the precision filter, which are connected to each other, and the clean oil tank,
It is provided in the return pipe and is operated so that the first clean oil returns to the clean oil tank through the return pipe in accordance with the height of the liquid surface of the first clean oil in the clean oil tank. A return valve (22), pressure detection means (51, 52) provided on the inlet side and the outlet side of the precision filter, the pressure detection means (51) on the inlet side of the precision filter, and the discharge pump. An electric valve (5
3), and between the electric valve and the outlet side of the discharge pump,
It has a pressure regulating valve (54) provided between it and the outlet side of the precision filter, and a temperature measuring means (56) provided in the clean oil tank, and further comprises a first pump sent from the discharge pump. Control means is provided for opening and closing the electrically operated valve in response to a signal from the pressure detecting means and a signal from the temperature measuring means so that the clean oil selectively passes through either the precision filter or the pressure regulating valve. ing.

An oil purifying apparatus according to an eighth aspect is the oil purifying apparatus according to the first or seventh aspect, wherein the precision filter (18) selects an oil content or a water content contained in the first cleaning oil. It is characterized in that it has an element for oil removal or an element for water removal which can be exchanged as needed for the purpose of effective removal.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention is shown in FIGS.
Will be described with reference to. The configuration of the oil cleaning device according to the first example of the embodiment of the present invention will be described with reference to FIG. This oil cleaning device is used for cleaning lubricating oil in an internal combustion engine such as a diesel engine. In the lubricating oil of the diesel engine, minute carbon and the like (insoluble matter) due to combustion residues from the cylinder are mixed and gradually accumulated during engine operation. Since this carbon is hard, if it increases in the lubricating oil, the bearings of the engine, crank pin metal, sliding parts such as the piston and cylinder liner will gradually wear away, and if this progresses, there is a risk of damage to the bearing, for example. It will be in a state.

Therefore, in general, a small engine such as a vehicle is frequently replaced with lubricating oil, and a medium or large engine having a large amount of lubricating oil is equipped with a lubricating oil cleaning device to lubricate insoluble matter. Removed from oil.

The insoluble matter in the lubricating oil contains carbon which is extremely fine, about 3 to 5 μm, and these carbons are kept in a fine state by the additive (dispersant) in the lubricating oil. Therefore, it cannot be easily removed by the conventional oil cleaning device.

In FIG. 1, a suction pump 12 is provided in a pipe 11 led from a sump tank of an engine (not shown). The discharge side of the suction pump 12 is the centrifugal separator 1.
It is led to the introduction port of 3. As the centrifuge 13 of this example, a centrifuge 13 which can separate the lubricating oil and the sludge into two layers and discharge the sludge in a solid state without adding water at the time of use is used. This centrifuge 13 can separate and remove large particles of approximately 10 μm or more from the insoluble matter.

The clean oil discharged after being processed by the centrifugal separator 13 is referred to as a first clean oil. The first clean oil still contains insoluble matter such as fine carbon that could not be removed by centrifugation. The first clean oil is guided to the clean oil tank 15 through the pipe 14 and is stored therein. The clean oil tank 15 is provided with a discharge pipe 16 for guiding the first clean oil to the outside. Discharge pipe 1
The suction port 6 is opened near the bottom surface in the clean oil tank 15.

A discharge pump 17 for sucking the first clean oil from the clean oil tank 15 and sending it out is connected to the discharge pipe 16. The discharge pump 17 is a constant capacity pump, and its capacity is larger than that of the suction pump 12.

The discharge side of the discharge pump 17 is the precision filter 1
It is connected to 8 entrances. The precision filter 18 has a function of passing the first clean oil supplied from the discharge pump 17 for further purification. Here, what refine | purified the 1st clean oil with the precision filter 18 is called a 2nd clean oil. The precision filter 18 can capture insoluble matter of 5 μm or less. The withstand pressure is 0.2 MPa or more, and the filter element is less likely to be damaged even if the pressure is increased to increase the flow rate of the lubricating oil passing through the precision filter 18. In this example, the pressure is 0.4 MPa. As the actual element constituting the precision filter 18, various elements such as a non-woven fabric element, a roll type paper filter, a laminated type paper filter and the like can be adopted.

FIG. 2 is a graph showing the measurement results of pressure-temperature-flow rate showing the performance of the precision filter 18 in the oil cleaning apparatus of this example. Here, in the oil cleaning apparatus of this example, since the filter having high pressure resistance is used, it is not necessary to heat the lubricating oil to increase the flow rate of the lubricating oil to reduce the viscosity appropriately, and the heater is not necessary. . However, in order to examine the characteristics of the precision filter 18 under the same conditions as when the engine was operating, various experiments were conducted on the pressure-flow rate relationship by setting the temperature of the lubricating oil with a heater. That is, the graph of FIG. 2 shows the relationship of the flow rate corresponding to the temperature of the lubricating oil, using the pressure applied to the precision filter 18 as a parameter.

Filter with low withstand voltage (eg, about 0.05M)
In the conventional case of using (about Pa), the lubricating oil had to be heated up to about 80 ° C. in order to properly exhibit the function as a filter, but in this example, since the pressure resistance is high, heating is especially required. Even without it, a sufficient flow rate can be obtained without increasing the pressure of the lubricating oil and damaging the filter.

The pipe 19 connected to the outlet side of the precision filter 18 is directly led to the sump tank of the engine. That is, the lubricating oil (second clean oil) that has passed through the precision filter 18 under the pressure of the discharge pump 17 is returned to the engine as it is. Therefore, although the back pressure is applied to the precision filter 18 due to the resistance of the pipe 19 on the filter outlet side, the precision filter 18 of this example has a larger pressure resistance performance than the conventional one as described above (for example, Conventional 0.05 MPa
However, the filtration process can be performed at a sufficient flow rate by applying a necessary high pressure without seeing inconvenience such as element damage.

The discharge pump 17 and the precision filter 1
A return pipe 21 connects the pipe 20 connecting the 8 and the clean oil tank 15. That is, a return pipe 21 branched from a pipe 20 connecting the discharge pump 17 and the precision filter 18 is introduced into the clean oil tank 15. A return valve 22 as a liquid level control device is connected to the end of the return pipe 21 in the clean oil tank 15. The open end of the outlet pipe of the return valve 22 is located below the liquid level L of the first clean oil stored in the clean oil tank 15. Further, the clean oil tank 15 is provided with a liquid level gauge 23, and the level of the liquid level L of the first clean oil in the clean oil tank 15 can be detected.

The return valve 22 is opened and closed according to the height of the liquid level L of the first clean oil in the clean oil tank 15.
A part of the first clean oil sent from the clean oil tank 15 by the discharge pump 17 does not enter the precision filter 18 depending on the level of the liquid level L and enters the clean oil tank 15 via the return pipe 21. It is configured to return.

That is, a ball tap 24 is connected to the operation portion of the return valve 22 as an operation means of a liquid level control device which operates the operation portion corresponding to the liquid level L. According to this ball tap 24, the opening degree of the return valve 22 changes depending on the level of the liquid level L of the first lubricating oil in the clean oil tank 15, and the amount of lubricating oil returned from the discharge pump 17 to the clean oil tank 15 is increased. Change. When the liquid level L exceeds the predetermined level, the return valve 22 is closed, and almost the entire amount of the discharge pump 17 is supplied to the precision filter 18.

Normally, the initial filling amount of the lubricating oil is determined so that the opening of the return valve 22 is about half and the liquid level L of the lubricating oil in the clean oil tank 15 is maintained. In addition, the return valve 2
The discharge pressure of the discharge pump 17 is determined by the opening degree of 2.

For example, assuming that a part (for example, 60%) of the first clean oil discharged by the discharge pump 17 is supplied to the precision filter 18 and the rest (for example, 40%) is returned to the clean oil tank 15. Since the remaining lubricating oil is under pressure, the first clean oil discharged from the outlet of the return pipe 21 stirs the lubricant oil in the clean oil tank 15, and sludge is generated at the bottom of the clean oil tank 15. It is prevented from accumulating.

During operation, the suction pump 12 and the discharge pump 17 are controlled by the control means 25 in accordance with the information from the liquid level gauge 23, and the first clean oil in the clean oil tank 15 has the proper liquid level described above. Hold L.

In this embodiment, the discharge pump 17 is selected to have a capacity larger than that of the suction pump 12 in order to return the lubricating oil sent from the suction pump 12, and both pumps 12 and 17 are operated. Then, the first oil in the clean oil tank 15
There is a possibility that the liquid level L of the clean oil decreases and the discharge pump 17 sucks in air and collects air in the precision filter 18, which impedes filtration. However, according to this example, the liquid level L in the clean oil tank 15 is controlled by operating the return valve 22 provided in the return pipe 21 by opening and closing the ball tap 24 as described above. Precision filter 18
It is possible to prevent the accumulation of air in the.

A bypass pipe 26 is provided before and after the precision filter 18, and a bypass valve 27 is provided in the bypass pipe 26. A pressure detecting means 28 is provided in front of the precision filter 18 in the flow direction and between the branch portion of the return pipe 21 and the branch portion of the bypass pipe line 26. The output of the pressure detection means 28 is sent to the control unit 25, and the control unit 25 can control the opening / closing of the bypass valve 27. Therefore, when the pressure detection unit 28 detects a pressure exceeding a predetermined value and sends it to the control unit 25, the control unit 25 issues an alarm and the bypass valve 2
7 is opened and the first lubricating oil is returned directly to the engine through the bypass line 26 without passing through the precision filter 18.

In the above construction, the dirty engine lubricating oil is sent to the centrifugal separator 13 by the suction pump 12, and the impurities such as solid content in the oil are centrifugally separated, and then collected in the clean oil tank 15. . Then, the first clean oil in the clean oil tank 15 is discharged from the precision filter 1 by the discharge pump 17.
8 and the impurities that could not be removed by the centrifuge 13 in the previous stage are also filtered and directly returned to the engine. Here, since the temperature of the lubricating oil is low and the viscosity is high when the engine is started, the pressure of the lubricating oil supplied to the precision filter 18 increases. In this case, the amount of lubricating oil that can be processed by the precision filter 18 decreases, and the amount of returning lubricating oil increases. Due to this increase, the lubricating oil liquid level L of the clean oil tank 15 rises, and the ball tap 24 narrows the valve opening of the return valve 22, so that the pressure of the discharge pump 17 further rises.

Since the lubricating oil temperature rises due to the increase in the amount of lubricating oil returned (increase in circulation amount) and the increase in discharge pressure, the viscosity of lubricating oil decreases and the amount of lubricating oil that can pass through the precision filter 18 increases. As a result, the discharge pressure of the discharge pump 17 and the lubricating oil level L of the clean oil tank 15 are decreased, and normal operation can be restored.

According to the present invention, a large back pressure is applied to the precision filter 18 due to the resistance of the pipe 19 on the filter outlet side due to the direct oil return. Since it has a large pressure resistance, the filtration process can be continued at a sufficient flow rate by applying a necessary high pressure. Further, when the pressure detecting means 28 detects a pressure exceeding a predetermined value, the bypass valve 27 is opened by the control unit 25, so that the lubricating oil is directly supplied to the engine through the bypass pipe line 26 without damaging the precision filter 18. Can be returned.

Next, an oil cleaning device according to a second example of the embodiment of the present invention will be described with reference to FIGS. The same components as those in the first example are designated by the same reference numerals as those in FIG. 1 and their description is omitted.

In this example, pressure transmitters 51 and 52 as pressure detecting means are provided on the inlet side and the outlet side of the precision filter 18, respectively.
Is configured to be able to detect the differential pressure applied to. An electric valve 53 is provided between the pressure detection means 51 on the inlet side of the precision filter 18 and the outlet side of the discharge pump 17. Also, the electric valve 5
3, a pressure regulating valve 54 (operating pressure is 0.3 MPa, for example) is provided between the outlet side of the discharge pump 17 and the outlet side of the precision filter 18. Further, between the pressure regulating valve 54 and the outlet side of the precision filter 18, a pressure regulating valve 55 (operating pressure is 0.05MP as an example).
a) is provided. The pressure regulating valve 55 having a pressure of 0.3 MPa is provided for bypassing the precision filter 18.
The value of 3 MPa is the differential pressure limit of the precision filter 18, and also functions as a safety valve in the event that the motor-operated valve 53 sticks. Further, the clean oil tank 15 is provided with a resistance temperature detector 56 as a temperature measuring means, and the temperature of the first clean oil in the clean oil tank 15 can be measured.

Although not shown in FIG. 3, in the present embodiment, the first clean oil sent from the discharge pump 17 is selectively passed through either the precision filter 18 or the pressure regulating valve 54. Control means is provided which can open and close the motor-operated valve 53 and the pressure regulating valve 54 in response to signals from the pressure detecting means 51 and 52 and a signal from the temperature measuring resistor 56. This control means corresponds to the control means 25 in the first example shown in FIG.

The operation of the above configuration will be described. In this example, the temperature of the fluid is detected by the resistance temperature detector 56, the differential pressure of the precision filter is detected by the pressure detection means 51, 52, and the motor-operated valve 53 is opened / closed based on these values, thereby performing the precision filter. The purpose is to bypass the liquid passing through 18 to the pressure regulating valve 54 as necessary to prevent clogging and damage of the precision filter 18.

That is, the pressure transmitters 51, 52
And the detection signal of the resistance temperature detector 56, the control means judges the three cases of "normal time", "low temperature time", and "clogging time",
The motor-operated valve 53 is controlled to be opened / closed depending on each case to extend the filter life. In the above three cases, the pressure difference between the pressure transmitters 51 and 52 at a certain threshold (a certain value). Larger or smaller than) and the fluid temperature high or low (higher or lower than a certain value) with a certain threshold of the resistance temperature detector 56 as a boundary, or the pressure transmitter 51, The opening degree of the motor-operated valve 53 may be controlled stepwise and continuously by a combination of continuous detection values output by 52 and the resistance temperature detector 56. For example,
When the oil temperature is low, the resistance of the filter is large, so the motor-operated valve 53 may be throttled to reduce the flow rate to the filter so that the differential pressure of the filter does not exceed a certain threshold value.

In FIG. 3, the precision filter 18 is in a state of little clogging, the temperature of the fluid is high, and the differential pressure of the precision filter 18 is small. The motor operated valve 53 is opened, and the liquid is flowing through the precision filter 18.

In FIG. 4, the filter is prevented from being damaged due to an increase in liquid viscosity due to a low temperature and the life of the filter is extended. That is, in this state, the temperature of the fluid is low,
When the differential pressure of the precision filter 18 is large, the motor operated valve 5
3 is closed and the liquid is made to bypass the pressure regulating valve 54.

FIG. 5 shows a case where the precision filter 18 is clogged. That is, this state is when the temperature of the fluid is high and the differential pressure of the precision filter 18 is large, and the motor-operated valve 53 is closed and the liquid is bypassed by the pressure regulating valve 54.

When it is expected that the liquid will be contaminated so much that it will be clogged immediately when it flows through the precision filter, the motor-operated valve 53 is closed to bypass the liquid and bypass the precision filter 18. Shut off the flow of the liquid and clean the liquid only with the centrifuge 13 (shown in FIG. 1),
When the liquid becomes less contaminated, the motor-operated valve 53 is opened to finish the cleaning with the precision filter 18.
It is good to extend the filter life.

Next, in the return pipe 21 of this embodiment, a manual discharge valve 50 is provided upstream of the return valve 22. Normally, a part of the liquid discharged from the discharge pump 17 by the ball tap 24 returns to the clean oil tank (liquid receiver) 15 and the liquid surface is kept constant, so that the discharge pump 17 does not inhale the air.

According to the above construction, when it is necessary to discharge the liquid in the clean oil tank (liquid receiver) 15 for maintenance or the like, the drain valve 50 is closed to shut off the oil return. Most of the liquid in the clean oil tank (liquid receiver) 15 can be discharged.

In the first example (FIGS. 1 and 2) and the second example (FIGS. 3 to 5) described above, the precision filter 18 is used.
Can be arbitrarily replaced with an element having various functions according to the purpose. For example, as shown in FIG. 6, the precision filter includes a case 60 made of steel having high rigidity.
A device in which a plurality of elements 61 (8 in the illustrated example) are arranged and configured so as to match the fluid can be provided. This case can be easily separated up and down to replace the internal element 61. For example, usually using a filter element suitable for removing carbon in the liquid to be treated, if you want to remove the water in a timely manner, replace the element with an excellent water removing action,
Further, when it is desired to remove the oil content, the element can be replaced with an element excellent in the oil content removal action.

Drain valves are provided on the upper and lower parts of the case 60, and the separated oil can be extracted from the upper part of the case 60 and the separated water can be extracted from the lower part of the case 60 for processing.

FIGS. 7 and 8 schematically show the structure and function of a filter element used to remove water existing in oil in an emulsion state from the oil.

In FIG. 7, a part of a filter in which filter elements are wound in layers of concentric circles is shown as a cross section, and fine particles 73 of water in oil are arranged between two overlapping elements 71, 72. This is a state in which the particles are forcibly assembled by the gradient and become coarse particles 74 as they move downward.

In FIG. 8, the fibrous filter element 8
0 shows the cross section of 0, and the water particles 81
To the filter element 80 to form a water film,
The size of the water droplet 82 is increased in order to form water droplets 82 having a size of mm, and the water droplets 82 are discharged to the outside of the filter. The water droplets 82 settle in the lower part due to the difference in specific gravity from the oil.

In the cutting fluid, oil as a lubricant during cutting is dispersed as an emulsion in water. However, when the oil is mixed from a machine or the like, the mixed oil is different from the oil as a lubricant on the water surface. To surface. This is generally called trump oil. This playing oil must be removed because it causes the cutting fluid to rot and has a bad odor. Further, the water content in the cutting fluid causes corrosion of the machine. However,
In this example, as described above, the filter element can be replaced with a filter element having an appropriate function as required, so that these unnecessary oil and water can be easily separated and removed.

As shown in FIG. 3, in the first example, a pressure regulating valve 55 having an operating pressure of 0.05 MPa is provided on the outlet side of the precision filter 18. The precision filter 18 of this example is
As shown in FIG. 6, since the fluid is vertically long and has a structure in which the fluid enters from the bottom and exits from the bottom, air easily collects in the upper part, and an air vent valve (not shown) is provided. If the piping resistance (back pressure) at the filter outlet is low when this valve is opened, the fluid may not flow to the upper part of the filter because the upper part of the filter is not filled with the fluid and air does not escape. Therefore, as in the second example shown in FIG. 3, a pressure regulating valve 55 is provided on the outlet side of the precision filter 18 to increase the pressure inside the filter so that air can be surely released.

The oil cleaning device described above is applied to a machine that circulates and uses some working oil, and is used for cleaning lubricating oil in an internal combustion engine such as a diesel engine. However, the term "oil" that the oil cleaning apparatus of the present invention applies to includes not only lubricating oil, but also working oil, cutting oil, and cooling oil (100% oil content).
In addition to those), it also includes water-soluble cutting oil (also called water-soluble cutting fluid), water-soluble lubricant, etc., in which most of the water content is contained. In other words, the term "oil" in the present invention includes a broad sense synthetic consisting of conventional coolant and synthetic coolant. Synthetic in this broad sense is, more specifically, emulsion type and solve (microemulsion) type which are mineral oils or synthetic oils, soluble type and chemical solution type which are water-soluble lubricants, and synthetic oils and water-soluble lubricants. It also includes hybrids of agents.

[0057]

According to the present invention, the lubricating oil processed by the centrifuge is discharged from the clean oil tank by the discharge pump, passed through the precision filter having sufficient pressure resistance, and further processed. A return valve was provided in the pipe connecting the front of the clean oil tank and the clean oil tank, and this was controlled according to the height of the liquid level in the clean oil tank, so the following effects could be obtained. .

(1) Since the precision filter having a high pressure resistance is used even when the temperature of the lubricating oil is low and the viscosity is high, the lubricating oil can be supplied to the precision filter at a high pressure. Therefore, the heater for heating the lubricating oil, which has been conventionally required to avoid this problem, is no longer required. (2) Since the precision filter with high pressure resistance is adopted, the inconvenience caused by the back pressure of the filter is reduced, and the lubricating oil after passing through the filter can be directly returned to the engine or the like. (3) Since the liquid level control unit can maintain a constant liquid level in the tank by providing a pipe from the outlet side of the discharge pump to the clean oil tank, it is possible to eliminate the intake of air into the discharge pump,
Air is prevented from accumulating in the precision filter.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an embodiment of an oil cleaning apparatus of the present invention.

FIG. 2 is a diagram showing characteristics of a precision filter used in the embodiment of the oil cleaning apparatus of the present invention.

FIG. 3 is a diagram showing another example of the embodiment of the oil cleaning device of the present invention, and is a diagram showing a state in which an electric valve is opened.

FIG. 4 is a view showing another example of the embodiment of the oil cleaning apparatus of the present invention, and is a view showing a state in which the electric valve is closed.

FIG. 5 is a view showing another example of the embodiment of the oil cleaning apparatus of the present invention, and is a view showing a state where the electric valve is closed when the precision filter is clogged.

FIG. 6 is a partially cutaway front view of a precision filter used in the embodiment of the oil cleaning apparatus of the present invention.

FIG. 7 is a diagram schematically showing the structure and function of a replacement element (for water) of a precision filter used in the embodiment of the oil cleaning apparatus of the present invention.

FIG. 8 is a diagram schematically showing the structure and function of a replacement element (for oil content) of a precision filter used in the embodiment of the oil cleaning apparatus of the present invention.

FIG. 9 is a configuration diagram of a conventional oil cleaning device.

10 is a diagram showing the outlet temperature of the filter heater and the pressure at the filter inlet of the filter in the oil cleaning apparatus shown in FIG.

[Explanation of symbols]

11, 14, 11, 19, 20, ... Piping, 12 ... Suction pump, 13 ... Centrifuge, 15 ... Clean oil tank, 17 ... Discharge pump, 18 ... Precision filter, 21 ... Return piping, 22
... Return valve, 24 ... Ball tap as return valve operating means, 25 ... Control part.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazumi Imai             1300 Okayama, Niigata City, Niigata Niigata Iron Works Co., Ltd.             In-house

Claims (8)

[Claims] 1. An oil cleaning device provided in a machine for circulating oil for cleaning the oil, comprising: a suction pump for pumping the oil used in the machine; and a pump for pumping the oil used by the suction pump. A centrifugal separator that removes insoluble matter from the oil to obtain the first clean oil, a clean oil tank that stores the first clean oil supplied from the centrifuge, and a first clean oil tank And a function of passing the first clean oil supplied from the discharge pump into a second clean oil, the second clean oil directly returning to the machine. And a precision filter having pressure resistance capable of withstanding a back pressure generated by the resistance of the pipe, and between the discharge pump and the precision filter connected to each other and the cleaning device. With the return pipe connecting to the oil tank Provided in the return pipe, and operated such that the first clean oil returns to the clean oil tank via the return pipe in accordance with the height of the liquid level of the first clean oil in the clean oil tank. An oil purifier equipped with a return valve. 2. The oil cleaning device according to claim 1, further comprising valve operating means for changing the opening of the return valve according to the height of the liquid surface of the first clean oil in the clean oil tank. 3. The oil cleaning apparatus according to claim 1, further comprising a liquid level gauge that detects a height of a liquid surface of the first clean oil in the clean oil tank. 4. The suction port of the suction side pipe of the discharge pump is opened near the bottom surface of the clean oil tank, and the discharge port of the return pipe is located above the first clean oil level of the clean oil tank. The oil cleaning device according to claim 1, wherein the oil cleaning device is arranged so as to face downward. 5. The pressure detecting means is further provided between the branch of the return pipe and the inlet of the precision filter, and a relief valve connecting the inlet and the outlet of the precision filter. The oil cleaning device according to claim 1, wherein the relief valve is opened and the first clean oil sent from the discharge pump bypasses the precision filter when the rise of the oil is detected. . 6. The oil cleaning device according to claim 1, wherein a discharge valve is provided upstream of the return valve in the return pipe. 7. An oil cleaning device provided for a machine that circulates oil for cleaning the oil, comprising: an intake pump for pumping the oil used in the machine; and a pump for pumping the oil used by the suction pump. A centrifugal separator that removes insoluble matter from the oil to obtain the first clean oil, a clean oil tank that stores the first clean oil supplied from the centrifuge, and a first clean oil tank And a function of passing the first clean oil supplied from the discharge pump into a second clean oil, the second clean oil directly returning to the machine. And a precision filter having pressure resistance capable of withstanding a back pressure generated by the resistance of the pipe, and between the discharge pump and the precision filter connected to each other and the cleaning device. With the return pipe connecting to the oil tank Provided in the return pipe, and operated such that the first clean oil returns to the clean oil tank via the return pipe in accordance with the height of the liquid level of the first clean oil in the clean oil tank. Return valve, pressure detecting means provided on the inlet side and the outlet side of the precision filter, and an electric motor provided between the pressure detecting means on the inlet side of the precision filter and the outlet side of the discharge pump. Valve, a pressure regulating valve provided between the motor-operated valve and the outlet side of the discharge pump, and between the outlet side of the precision filter, a temperature measuring unit provided in the clean oil tank, and the discharge pump In order to selectively pass the first clean oil sent from the precision filter or the pressure regulating valve, the motor-operated valve is operated according to the signal from the pressure detecting means and the signal from the temperature measuring means. Control means for opening and closing, Purifier. 8. The precision filter is an element for removing oil or a element for removing water, which is replaceable as necessary in order to selectively remove oil or water contained in the first clean oil. The oil cleaning device according to claim 1 or 7, further comprising: