JPH051814A - Fuel filter - Google Patents

Abstract

PURPOSE:To remove dusts, moisture, etc., in the fuel and supply clean fuel to an engine by providing a fuel filter that works also as an oil-water separator in an intermediate position in the fuel distribution pipe that connects a fuel tank and the engine. CONSTITUTION:A filter element 22 that extends axially in the housing 9 of a fuel filter 21 is provided. A cap 27 covers the filter element 26 partially from its bottom side, and a water storage chamber 31 for storing the water M in the fuel F is formed between the cap 27 and filter case 11 on the side of the lower section of a fuel flow-in chamber 29. The fuel F is filtered by the element 26 and clean fuel FB flows into the flow-out chamber 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel filter suitable for use in the middle of a fuel supply pipe of a small construction machine or the like.

[0002]

2. Description of the Related Art Here, a conventional fuel supply device used in, for example, a construction machine will be described with reference to FIGS.

In the figure, reference numeral 1 denotes an engine as a prime mover of a construction machine. A fuel injection device 2 is attached to the engine 1, and the fuel supplied from the fuel injection device 2 into the engine 1 is burned. , The output is taken from the engine 1.

Reference numeral 3 denotes a fuel tank for storing the fuel F. A fuel oil supply port 3A is formed on the upper side of the fuel tank 3 and a fuel outlet port 3B is formed on the lower side. Reference numeral 4 denotes a filter provided so as to cover the fuel outlet 3B of the fuel tank 3. The filter 4 has a mesh structure of about 150 μm, and is a large particle dust contained in the fuel F in the fuel tank 3. And the fuel F from which large dust particles have been removed is circulated from the fuel outlet 3B toward the fuel supply pipe 5 described later. As a result, the failure of the fuel pump 7 described later is prevented, and the reliability of operation is achieved.

Reference numeral 5 denotes a fuel supply pipe connected between the fuel outlet 3B of the fuel tank 3 and the fuel injection device 2 of the engine 1. The fuel supply pipe 5 supplies the fuel F in the fuel tank 3 to the engine. Supply to 1. Further, the fuel supply pipe 5
An oil / water separator 6, a fuel pump 7, and a fuel filter 8, which will be described later, are sequentially connected in the middle of.

Reference numeral 6 denotes an oil / water separator. The oil / water separator 6 is provided with a cylindrical case 6A having a bottom and a lid which is provided so as to cover the case 6A and which is connected in the middle of the fuel supply pipe 5. And a portion 6B, and the inlet of the fuel supply pipe 5 inserted into the lid 6B is bent toward the bottom side of the case 6A. Then, in the oil / water separator 6, when the water M is contained in the fuel F flowing from the fuel tank 3, the water M is accumulated on the bottom side of the case 6A,
The oil FA is separated, and the fuel FA from which the water M has been removed is circulated to the downstream side of the fuel supply pipe 5.

Reference numeral 7 denotes a fuel pump, which is driven by an engine, an electric motor (not shown),
The fuel FA is sucked from the suction port, and the fuel FA is discharged from the discharge port (neither is shown).

Reference numeral 8 denotes a fuel filter. The fuel filter 8 is, as shown in FIG. 7 and FIG.
The housing 9 is composed of a filter case 11 and a filter element 12 mounted in the housing 9.

Reference numeral 10 denotes a lid body formed in a cylindrical shape with a lid,
The lid 10 includes a lid-shaped cylindrical portion 10A, a large-diameter case mounting portion 10B located on the opening side of the cylindrical portion 10A and having an internal thread portion 10B1 formed on the inner peripheral surface thereof, and the case mounting portion. Part 10
It is located on the inner peripheral side of B and has an internal thread portion 10C on the inner peripheral surface on the opening side
Small diameter filter element mounting part 10C with 1 formed
And a pipe fixing hole 10D, 10E to which the inflow side end 5A and the outflow side end 5B of the fuel supply pipe 5 are fixed is formed in the peripheral wall of the cylindrical portion 10A so as to face each other in the radial direction. There is.

Reference numeral 11 denotes a filter case, which is made of a transparent resin material and has a bottomed cylindrical shape. The outer peripheral surface on the opening side has a female thread portion 10B1 of a case mounting portion 10B of the lid 10. Male thread 11A screwed to
Are formed. Further, since the filter case 11 is made of a transparent resin material, dirt on the filter element 12 described later and fuel accumulated inside can be visually confirmed.

Reference numeral 12 denotes a filter element which is attached to the filter element attachment portion 10C of the lid 10 and extends upward and downward in the filter case 11. The filter element 12 has a large number of through holes 13A, 13A ,. A cylindrical holding cylinder 13 bored in the radial direction, and an inner peripheral surface fixed to the outer peripheral surface on the upper end side of the holding cylinder 13, and the outer peripheral side is screwed to the female screw portion 10C1 of the filter element mounting portion 10C. A thick-walled annular upper element retainer 14 serving as a male screw portion 14A, a lower element retainer 15 fixed to the lower end surface of the holding cylinder 13 and formed in a thin disk shape, and an outer peripheral side of the retaining cylinder 13. Is located at the
5 and is composed of an element 16 which is formed by folding back a filter paper or the like having a mesh diameter of about 10 to 30 μm in a bellows shape in the radial direction.

Reference numerals 18 and 19 denote a fuel inflow chamber and a fuel outflow chamber defined by a filter element 12 in a housing 9 of the fuel filter 8, and the inflow chamber 18 is a fuel supply pipe 5.
Is formed so as to connect the inflow side end portion 5A of the filter element 12 and the outer peripheral side of the element 16 of the filter element 12 to each other.
9 is formed so as to connect the outflow side end portion 5B of the fuel supply pipe 5 and the inner peripheral side of the holding cylinder 13 of the filter element 12.

In the fuel filter 8 thus constructed, the fuel FA discharged from the fuel pump 7 flows into the inflow chamber 18 through the inflow side end 5A of the fuel supply pipe 5, and the fuel FA is discharged. FA flows to the outflow chamber 19 through the element 16 of the filter element 12 and each through hole 13A of the holding cylinder 13 by the discharge pressure from the fuel pump 7, and at this time, the dust contained in the fuel FA is captured by the element 16. Then, the clean fuel FB is circulated to the outflow chamber 19. Then, the clean fuel FB in the outflow chamber 19 is sequentially supplied from the outflow side end portion 5B of the fuel supply pipe 5 toward the fuel injection device 2 of the engine 1.

The fuel supply device according to the prior art has the above-described structure. By driving the fuel pump 7, the fuel F in the fuel tank 3 is supplied to the fuel injection device 2 of the engine 1 through the fuel supply pipe 5. The fuel F in the fuel tank 3 is supplied to the fuel injection device 2 of the engine 1 as clean fuel FB. In this case, the filter 4 provided so as to cover the fuel outlet 3B of the fuel tank 3 captures large-sized dust in the fuel tank 3, and then an oil-water separator provided in the middle of the fuel supply pipe 5. 6, fuel F
Is separated into water M and fuel FA containing no water M. Further, a fuel filter 8 provided on the downstream side of the oil / water separator 6 and provided in the middle of the fuel supply pipe 5 allows the fuel F
The dust contained in A can be captured by the element 16 of the filter element 12 and supplied to the fuel injection device 2 of the engine 1 as clean fuel FB.

[0015]

By the way, in the above-described fuel supply device of the prior art, the filter 4 is provided at the bottom of the fuel tank 3, and the fuel supply pipe 5 from the fuel tank 3 to the fuel injection device 2 of the engine 1 is provided. Since the oil-water separator 6, the fuel pump 7 and the fuel filter 8 are separately connected in the middle of the above, the number of parts is increased and a wide mounting space is required. Therefore, in the case of large construction machinery,
Although the installation space for the fuel supply device can be secured in the machine room, it is difficult to install the fuel supply device, especially in small construction machines, because the installation space for the fuel supply device in the machine room is small. ..

Further, there is a problem that the workability at the time of assembly is poor, and the workability of inspection, maintenance, replacement, etc. is deteriorated. Further, since the number of connecting parts increases in the middle of the fuel supply pipe 5, there is a risk of fuel leakage and the like, and there is a problem that reliability decreases.

Looking at the inside of the fuel filter 8, it is ideal that the fuel FA is filled in the inflow chamber 18 as shown in FIG. 7, but together with the air remaining in the fuel filter 8 during assembly, The emulsified air mixed in the fuel FA during the operation of the engine 1 actually accumulates as air A from the middle to the upper space in the inflow chamber 18 as shown in FIG. 9 as time passes. ..

Since the filter element 16 is wetted by the fuel FA, surface tension acts on the surface of the element 16 to increase the air passage resistance, and the inflow chamber 18
The fuel FA therein flows from the lower part of the filter element 16 into the outflow chamber 19 and is pressure balanced in this state.

However, as described above, the air A is introduced into the inflow chamber 18.
In the state where the water is accumulated, not only the air cannot be discharged, but also because the filter case 11 is transparent, there is a concern that the user of the construction machine may be distrusted, such as lack of fuel, or that there is a problem. There is a problem of doing. Further, the air in the fuel filter 8 is supplied together with the fuel FB, which may cause the engine 1 to malfunction.

On the other hand, in order to make it easier to install the fuel supply device in the machine room of the small construction machine, it is considered that the oil / water separator 6 is simply removed from the middle of the fuel supply pipe 5 and only the fuel filter 8 is provided. Be done.

However, in this case, as shown in FIG. 10, the fuel F containing the water M flows into the fuel filter 8,
Moisture M gradually accumulates under the inflow chamber 18 of the fuel filter 8 (bottom side of the filter case 11), and the element 16
When the water M is collected up to the position, the entire surface of the element 16 gets wet due to surface tension, the water M permeates into the element 16, and the water M flows out into the outflow chamber 19. Then, since the water M permeates the element 16, the filtration area of the fuel F is reduced, and it becomes difficult to reliably perform oil-water separation, and the water M mixed in the outflow chamber 19 is mixed with the fuel FB. Is supplied to the fuel injection device 2 of the engine 1,
There is a problem that the rotation failure of the engine 1 occurs.

The present invention has been made in view of the above-mentioned problems of the prior art. When the present invention is used in a fuel supply system,
The oil-water separator can also be used, the number of parts can be reduced, and it can be installed in a narrow space like a small construction machine, improving workability such as replacement and ensuring that the fuel can be reliably cleaned. The purpose of the present invention is to provide a fuel filter.

[0023]

The features of the structure adopted by the present invention to solve the above-mentioned problems are that the filter element is formed in a bottomed tubular shape with a length dimension shorter than that of the filter element, A cap for separating water, which is located on the inflow chamber side and covers the filter element from the lower end side to an intermediate portion in the longitudinal direction, is attached, and is located between the cap and the housing on the lower side of the inflow chamber. To form a water reservoir.

[0024]

With the above structure, the water in the fuel containing the water flowing in from the upstream side of the fuel supply pipe can be separated at the lower side of the inflow chamber, and this water can be separated from the lower side of the housing and the cap. Can be stored in In addition, the fuel in the inflow chamber flows into the cap from the upper end of the cap, is filtered by the filter element, and flows toward the outflow chamber, and only the fuel purified from the outflow chamber is supplied to the engine. it can.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiments, the same components as those of the above-described conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 21 is located between the fuel tank 3 and the fuel pump 7 unlike the position of the fuel filter 8 according to the prior art, and is provided in the middle of the fuel supply pipe 5 of the present embodiment. 2 and 3, the fuel filter 21 is mounted in the housing 9 and a housing 9 including a lid 10 and a filter case 11 in substantially the same manner as the conventional fuel filter 8 described above. The filter element 22 is described later.

Reference numeral 22 denotes a filter element mounted on the filter element mounting portion 10C of the lid body 10. The filter element 22 has a plurality of through holes 23A, 23.
A cylindrical holding cylinder 23 in which A, ... Are bored in the radial direction, and an inner peripheral surface is fixed to the outer peripheral surface on the upper end side of the holding cylinder 23, and the outer peripheral side is the female screw portion 10C of the filter element mounting portion 10C.
A thick-walled annular upper element retainer 24 which is a male screw portion 24A screwed to 1, and a thin disc-shaped lower portion which is provided on the lower end side of the holding cylinder 23 and constitutes a part of a cap 27 described later. A filter paper or the like having a mesh diameter of about 10 to 30 μm is formed in a bellows shape in the radial direction, the filter element having a mesh diameter of about 10 to 30 μm. The tubular element 26 is formed by being folded back.

Reference numeral 27 denotes a water separating cap that partially covers the lower end surface and the outer peripheral surface of the element 26. The cap 27 has an inner diameter substantially the same as the outer diameter of the element 26 and has a length dimension. The element 28 comprises a tubular body 28 that is shorter than the element 26 by a predetermined dimension, and the tubular body 28 is formed in a bottomed tubular shape by fixing the inner peripheral side of the lower end to the outer peripheral side of the element retainer 25 in a liquid-tight manner. Then, the cap 27 leaves the upper portion of the element 26 and the element 2
6 is covered from the outside, and a water reservoir chamber 31 is formed in an inflow chamber 29, which will be described later, with the filter case 11.

Reference numerals 29 and 30 denote an inflow chamber and an outflow chamber defined by the filter element 22 in the housing 9 of the fuel filter 21, and the inflow chamber 29 is provided with the inflow side end portion 5A of the fuel supply pipe 5 and the filter element 22. Element 2
6 is formed so as to communicate with the outer peripheral side, and the outflow chamber 30 is formed so as to communicate between the outflow side end portion 5B of the fuel supply pipe 5 and the inner peripheral side of the holding cylinder 23 of the filter element 22. The lower part of the inflow chamber 29 is a water reservoir chamber 31 between the cap 27 and the filter case 11 below the upper opening of the tubular body 28.

The fuel filter 21 according to the present embodiment has the above-mentioned structure, and its basic operation is not different from that of the prior art.

However, in this embodiment, the filter element 22 provided in the housing 9 of the fuel filter 21 is formed into a bottomed cylindrical shape having a length dimension shorter than that of the element 26, and the outer peripheral surface of the element 26. Since the cap 27 is provided to partially cover the lower end side, even if the fuel F containing the water M flows from the fuel pump 3 into the fuel filter 21 through the fuel supply pipe 5 in the arrow direction, The fuel F is separated into the fuel F and the water M in a state where the fuel F and the water M are filled in a state where the fuel F is filled, and the water M can remain in the water storage chamber 31.
As described above, only the fuel F in the inflow chamber 29 is discharged from the cap 2
7 penetrates into the cap 27 from above the upper end and permeates through the through holes 23A of the element 26 and the holding cylinder 23 and flows into the outflow chamber 30. At this time, dust or the like in the fuel F is separated from the element. 26, the clean fuel FB can be captured from the outflow chamber 30 and circulates toward the fuel pump 7 via the downstream end 5B on the outflow side, and from the fuel pump 7 to the fuel injection device 2 of the engine 1. Can be supplied.

The fuel filter 2 ensures reliable oil-water separation.
1, the water M mixed from the fuel filter 21 causes the fuel FB to flow into the fuel injection device 2 of the engine 1.
Can be reliably prevented from being supplied to the engine, and the rotation failure of the engine 1 that has conventionally occurred can be effectively prevented.

Thus, in the fuel supply system according to the present embodiment, the fuel filter 21 having the cap 27 that partially covers the outer peripheral surface of the filter element 22 from below is provided in the middle of the fuel supply pipe 5 to provide the fuel filter. The water M and the dust in the fuel F can be surely removed by 21. Even if the filter 4 and the oil / water separator 6 used in the prior art are omitted, the fuel F is sufficiently clean fuel FB. be able to. As a result, the fuel filter 2
Since it is not necessary to provide an oil-water separator or the like separately from 1, the number of parts can be reliably reduced, and a large working space can be secured during mounting.

In particular, even when the machine room is small, such as in a small construction machine, the fuel supply device can be easily installed and the components such as the fuel filter 21 are inspected and maintained.
Exchange work can be easily performed. Moreover, since the number of connecting portions of the fuel supply pipe 5 can be reduced, the risk of fuel leakage can be reduced, and the reliability of the fuel supply device can be reliably improved.

Further, since the fuel filter 21 is connected to the upstream side of the fuel pump 7 and the fuel F containing dust can be prevented from flowing into the fuel pump 7, occurrence of abnormal wear of the fuel pump 7 can be prevented. The life of the fuel pump 7 and the engine 1 can be effectively extended.

On the other hand, the air remaining at the time of assembly or the air emulsified in the fuel F flows into the fuel filter 21 with the passage of time, and as shown in FIG. 4, the air A is the upper space of the inflow chamber 29. May accumulate in. However, by providing the cap 27 that partially covers the outer peripheral surface of the filter element 22 from the lower side, the element 2 is prevented by the fuel F.
By wetting 6, the surface tension acts on the surface of the element 26 and the air passage resistance increases. Therefore, the air A accumulated in the upper space does not flow into the outflow chamber 30 due to the fuel F already impregnated in the element 26, and only the fuel F in the inflow chamber 29 reaches the upper end of the cap 27. From above to enter the cap 27, and is filtered by the element 26 to obtain a clean fuel FB.
Flows toward the fuel pump 7 via the downstream end portion 5B on the outflow side.

Further, even when the operator visually checks in order to detect the amount of the water M in the fuel filter 21, when the water M does not reach the opening of the cap 27, the clean water outflows from the fuel filter 21. It was found that the fuel FB did not contain the water M, and before the upper limit of the water M reached near the opening of the cap 27, the filter cover 1
Since it suffices to remove 1 to remove the water M, the worker can continue the work operation with peace of mind.

Immediately after the fuel pump 7 is started after the removal of the water M, the air A flows into the inflow chamber 29.
Although entering the inside, the air A permeates the wet element 26 until the fuel F flowing into the inflow chamber 29 reaches the level of the upper end of the cap 27 with the passage of time. Spilled to 30. When the inflowing fuel F wets the element 26, the surface tension of the element 26 and the air A are pressure-balanced to be in the state of FIG.

Further, even when the air A accumulates in the fuel filter 21, the liquid level in the fuel F is above the opening of the cap 27, so that the air layer is at a height that cannot be seen from the filter case 11. Therefore, it is possible to eliminate the distrust of the user of the construction machine erroneously determining that the fuel is insufficient and to give the user a sense of security.

In the above embodiment, the filter case 1
1 is made of a transparent resin material so that stains on the filter element 22 and the like can be visually observed. Instead of this, the filter case 11 is made of an opaque resin material, a metal material or the like in a bottomed cylindrical shape. Good.

Further, in the above-mentioned embodiment, the cap 27 is described as being formed as a bottomed cylinder from the cylinder 28 and the lower element retainer 25, but the present invention is not limited to this, and it is integrally formed in advance. You may make it cover the bottomed cylindrical cap from the lower side of the filter element 22.

Further, the cap 27 of the above-mentioned embodiment has been described as being formed in a bottomed tubular shape by the cylindrical tubular body 28 and the disc-shaped lower element pressing member 25, but instead of this, FIG. As in the modified example shown in Fig. 5, the bottom element holding cap 25 'formed by the lower element holding 25' in which the lower element holding is formed in a square shape and the tubular body 28 'formed in the square tubular shape is used. Thus, the water storage chamber 31 may be formed below the inflow chamber 29. Further, the shape of the cap of the present invention is not limited to the cylindrical cap 27 and the rectangular tube-shaped cap 27 ', but the filter element 22
The filter case 1 is formed so as to cover the element 26 from the outside while leaving the upper portion of the element 26 from the lower side.
It is only necessary that the water reservoir chamber 31 is formed in the inflow chamber 29 between the first and second chambers.

[0043]

As described in detail above, according to the present invention, the inflow chamber and the outflow chamber for the fuel are defined in the housing by providing the filter element extending in the axial direction in the housing of the fuel filter. A cylindrical cap having a bottom is provided on the outer peripheral side of the filter element so as to cover the filter element from the lower end side to an intermediate portion, and is located on the lower side of the inflow chamber between the cap and the housing. Since the water storage chamber is formed, even if the fuel containing water flows into the inflow chamber from the fuel supply pipe, the water in the fuel can be separated at the lower side of the inflow chamber to capture the water,
It is possible to circulate clean fuel in the outflow chamber while removing dust and the like from the fuel in the inflow chamber. In addition, it is possible to reliably remove water without separately providing an oil-water separator or the like in the fuel supply pipe, reduce the number of parts and improve workability at the time of installation, and facilitate inspection and maintenance and replacement work. Therefore, clean fuel can be supplied to the engine.

Further, by providing the fuel filter of the present invention in the fuel supply device, it can be installed in a narrow space, and even when the machine room is small like a small construction machine,
It can be used effectively.

Further, even if the air in the fuel flows into the fuel filter, the air layer serving as an air reservoir is only formed above the upper end of the cap, so that the fuel level is sufficiently high. Therefore, when the user visually checks the liquid level from the outside of the housing, it is possible to eliminate the distrust of erroneously determining that the fuel level is insufficient and improve the reliability.

[Brief description of drawings]

FIG. 1 is an overall view showing a fuel supply device according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a fuel filter according to an embodiment of the present invention.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a vertical sectional view similar to FIG. 2, showing a state in which an air pocket is generated in the fuel filter of the present embodiment.

FIG. 5 is a sectional view similar to FIG. 3, showing a modified example of the present invention.

FIG. 6 is an overall view showing a fuel supply device according to the prior art.

FIG. 7 is a vertical cross-sectional view of a fuel filter according to the related art.

8 is a sectional view taken along the line VIII-VIII in FIG.

FIG. 9 is a vertical cross-sectional view showing a state in which an air pocket is generated in the fuel filter.

FIG. 10 is a vertical cross-sectional view showing a state in which a water pool and an air pool are formed in the fuel filter.

[Explanation of Codes] 1 Engine 3 Fuel Tank 5 Fuel Supply Pipe 9 Housing 10 Lid 11 Filter Case 21 Fuel Filter 22 Filter Element 25, 25 'Lower Element Presser 26 Element 27, 27' Cap 28, 28 'Cylindrical 29 Inflow chamber 30 Outflow chamber 31 Water reservoir F Fuel M Moisture

Claims (1)

Claim: What is claimed is: 1. A housing, which is formed as a closed container that extends upward and downward, and whose upper end is connected to the middle of a fuel supply pipe for supplying fuel in a fuel tank to an engine, and the housing. In order to divide the inside into a fuel inflow chamber and an outflow chamber,
A fuel filter comprising a tubular filter element that is provided to extend upward and downward in the housing, and filters the fuel on the inflow chamber side and allows it to flow to the outflow chamber side,
The filter element is formed in a cylindrical shape with a bottom having a length dimension shorter than that of the filter element, and is located on the inflow chamber side and covers the filter element from a lower end side to an intermediate portion in the length direction. A fuel filter, wherein a cap for water is attached, and a water reservoir is formed between the cap and the housing, the water reservoir being located at a lower side of the inflow chamber.