JP3337388B2 - Screen filter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen filter device effective for removing contamination (dust).

[0002]

2. Description of the Related Art As shown in FIG. 2 , a hydraulic circuit used in a working machine of a construction machine or the like includes a main pump 1 and a control valve 4 provided between a tank 2 and a hydraulic actuator 3 by a pilot pressure. In the pilot pressure control system, a screen filter device 7 is provided in a pipeline between a pilot pump 5 and a pilot valve (remote control valve) 6 operated by an operator of the construction machine. The screen filter device 7 removes contamination in oil.

As shown in FIG. 3 , a screen filter device 7 provided in a conventional pilot line is
A wire mesh screen 9 is provided on one end opening of the cylindrical filter case 8 in which the square nut portion 8a and the screw portion 8b are integrally formed.
Is fitted.

[0004]

In this conventional screen filter device 7, when the screen 9 is clogged due to contamination, an abnormal pressure loss occurs in the screen 9, and an abnormal pressure difference acting through the screen 9 is generated. May damage the screen 9.

Further, the contamination clogged on the screen 9 cannot be taken out of the pipeline as it is, and it is necessary to remove the screen filter device 7 from the pilot pipeline, so that maintenance cannot be easily performed.

An object of the present invention is to provide a screen filter device capable of preventing the occurrence of abnormal pressure loss at the time of clogging, and to reduce clogged contamination. It is an object of the present invention to provide a screen filter device that can be easily taken out.

[0007]

SUMMARY OF THE INVENTION The 請 Motomeko invention described in 1, a filter case inlet and outlet of fluid at both ends of the valve chamber is opened with the valve chamber is formed inside the valve chamber An inlet-side check valve body urged in a direction opposing the flow direction of the fluid and locked at the inlet and having a penetrating liquid passage hole; An inlet-side screen provided in the liquid hole, and an outlet-side check valve movably provided in the valve chamber and urged in the same direction as the flow direction of the fluid, locked at the outlet, and having a penetrating liquid passage hole. A screen filter device comprising a body, an outlet screen provided in a liquid passage hole of the outlet check valve body, and a dust discharge hole provided in a filter case and capable of opening a valve chamber to the outside.

[0008] When the inlet screen of the inlet check valve is clogged due to contamination and the pressure difference between the front and rear of the inlet screen increases, the inlet check valve retreats into the valve chamber and the filter moves backward. Since the entrance of the case is opened, abnormal high pressure does not act on the entrance screen. Contamination that has entered the valve chamber together with the fluid by opening the inlet check valve body is captured by the outlet screen of the outlet check valve body and accumulated in the valve chamber. Open the refuse discharge hole and take out the contamination in the valve chamber from the refuse discharge hole to the outside of the pipeline.

[0009] The invention described in claim 2 is the screen filter device according to claim 1, in which a pressure sensor is provided to the valve chamber.

When the pressure in the valve chamber is sensed by a pressure sensor, the pressure in the valve chamber increases when the screen of the outlet check valve is clogged, and the pressure sensor detects this clogging. Then, the dust discharge hole is opened, and the contamination in the valve chamber is discharged to the outside of the pipe through the dust discharge hole.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, one of the present invention shown in FIG. 1
This will be described with reference to the embodiment. The present screen filter apparatus, a pilot pump 5 shown in FIG. 2
Is preferably provided in the discharge pipeline of the main pump 1, but it is also possible to provide it in the discharge pipeline of the main pump 1.

Reference numeral 11 denotes a filter case. A valve chamber 12 is formed inside the filter case 11, and a fluid (hydraulic oil) inlet 13 and an outlet 14 are provided at both ends of the valve chamber 12.
Is open. An inlet valve seat 15 and an outlet valve seat 16 are formed on inner peripheral portions of the inlet 13 and the outlet 14, respectively .

In the valve chamber 12, an inlet-side check valve 17 and an outlet-side check valve 18 are provided movably.

A compression coil spring 21 is fitted between the concave portion 19 of the inlet check valve 17 and the concave portion 20 of the outlet check valve 18.
17 is urged to the inlet valve seat 15, and the outlet side check valve element 18 is urged to the outlet valve seat 16.

That is, the inlet-side check valve element 17 is urged by the compression coil spring 21 in a direction opposite to the fluid flow direction D and locked at the inlet valve seat 15. The body 18 is urged by the compression coil spring 21 in the same direction as the fluid flow direction D and is locked at the outlet valve seat 16.

The inlet-side check valve element 17 has a through-hole 23 formed in the center thereof, and an inlet-side screen 24 at the inlet side of the through-hole 23. This entrance screen 24
Is formed by a wire mesh 25 and a metal frame 26 and has an inlet-side check valve body.
17 fits into the recess 27 on the entrance side and is fixed by the locking ring 28
Have been. The outlet-side check valve element 18 has a through-hole 29 formed in the center thereof, and an outlet-side screen 31 provided on the outlet side of the through-hole 29.

The outlet side provided on the outlet side check valve element 18
The screen 31 is formed by a wire net 32 and a metal frame 33, and
The engagement ring is fitted into the outlet side concave portion 34 of the
Fixed by 35.

Further, a dust discharge hole 37 is provided in the filter case 11.
And a plug 38 is detachably screwed into the dust discharge hole 37. When the plug 38 is removed, the valve chamber 12 is opened to the outside via the dust discharge hole 37.

Further, a pressure extraction hole 41 is formed in the filter case 11 at a position where the pressure extraction hole 41 can reach the valve chamber 12, and a pressure sensor 43 is connected to the pressure extraction hole 41 through a conduit 42. Thereby, the pressure in the valve chamber 12 is detected.

Next, the operation of the embodiment shown in FIG. 1 will be described. The inlet screen 24 of the inlet check valve 17 will be described.
Captures and removes contamination in the fluid,
If the inlet screen 24 is clogged by contamination, the pressure loss (pressure difference) before and after the inlet screen 24 increases, and the inlet check valve 17 opposes the compression coil spring 21 due to the pressure difference. As a result, the inlet valve seat 15 of the filter case 11 is opened by retreating into the valve chamber 12, so that an abnormally high pressure does not act on the inlet screen 24.

The contamination that has flowed into the valve chamber 12 together with the fluid by opening the inlet check valve 17 and being captured by the outlet screen 31 of the outlet check valve 18 is captured by the valve chamber 12.
Stored in 12. The pressure in the valve chamber 12 is sensed by a pressure sensor 43.

If the outlet side screen 31 is clogged, the pressure in the valve chamber 12 increases. If this pressure increase is detected by the pressure sensor 43 and output to an alarm or the like, the clogging state is established. Remove the plug 38, open the waste discharge hole 37, and remove the contamination in the valve chamber 12 from the waste discharge hole 37.
Drain more out of the pilot pipeline.

[0023] Incidentally, screen filter device of the embodiment shown in Figure 1, because it is left-right symmetric shape with a bi-directional, may be used in the inlet 13 and outlet 14 in the opposite.

Further, the application of the screen filter device of the present invention is not limited to the pilot pipeline,
It can be applied to other fluid circuits. In particular, if provided immediately before the orifice in the pipeline, it is effective in preventing clogging of the orifice.

[0025]

According to the first aspect of the present invention, when the inlet side screen is clogged by contamination and the pressure difference before and after the inlet side screen becomes large, the inlet side check valve retreats into the valve chamber and the filter is retreated. Since the entrance of the case is opened, abnormal high pressure does not act on the entrance side screen, and the entrance side screen can be reliably prevented from being damaged. In addition, the contamination that has entered the valve chamber via the inlet check valve can be captured by the outlet screen of the outlet check valve and stored in the valve chamber. Furthermore, if you open the garbage discharge hole,
Contamination in the valve chamber can be easily taken out of the pipe through the dust discharge hole without removing the present apparatus from the pipe.

According to the second aspect of the present invention, since the pressure sensor is provided for the valve chamber, the clogging of the screen of the outlet-side check valve body can be automatically detected by the pressure sensor, and the contamination is reduced. Measures such as discharge from the room can be taken promptly.

[Brief description of the drawings]

An exemplary screen filter device according to the invention, FIG
It is sectional drawing which shows the form.

FIG. 2 is a circuit diagram illustrating a hydraulic circuit used in a working machine of a construction machine.

FIG. 3 is a sectional view showing a conventional screen filter device.

[Explanation of symbols]

 11 Filter case 12 Valve chamber 13 Inlet 14 Outlet 17 Inlet check valve 18 Outlet check valve 23 Liquid flow hole 24 Inlet screen 29 Liquid flow hole 31 Outlet screen 37 Dust discharge hole 43 Pressure sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B01D 35/02 B01D 29/01-29/075 B01D 35/14-35/157 F15B 20/00 F16K 15 / 00-15/20

Claims (2)

(57) [Claims] 1. A filter case having a valve chamber formed therein and having a fluid inlet and an outlet opened at both ends of the valve chamber, and a filter case movably provided in the valve chamber in a direction opposite to a fluid flow direction. Entrance-side check valve body which is urged and locked at the inlet and has a penetrating liquid passage hole, an inlet-side screen provided in the liquid passage hole of the inlet-side check valve body, and moves to the valve chamber An outlet-side check valve body that is freely provided, is urged in the same direction as the fluid flow direction, is locked at the outlet, and has a penetrating liquid passage hole, and a liquid passage hole of the outlet-side check valve body. A screen filter device comprising: an outlet-side screen provided; and a dust discharge hole provided in a filter case and capable of opening a valve chamber to the outside. 2. A screen filter according to claim 1, wherein a pressure sensor is provided to valve chamber.