AU654440B1 - Control system for an S-shaped gate valve pressing mechanism - Google Patents

Description

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AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT P/00/011 Regulation 3.2 S. S Invention Title: CONTROL SYSTEM FOR AN S-SHAPED GATE VALVE PRESSING MECHANISM The following statement is a full description of this invention, including the best method of performing it known to us: GH&CO REF: P09991-FA:DAA:RK '1 CONTROL SYSTEM FOR AN S-SHAPED GATE VALVE PRESSING MECHANISM BACKGROUND OF THE INVENTION: i. Field of the Invention: The present invention relates to a control system for an S-shaped gate valve pressing mechanism of a concrete pump.

2. Description of the Prior Art: Fig. 2 is a perspective view showing an S-shaped gate valve pressing mechanism of a concrete pump in the prior art.

Explaining the S-shaped gate valve pressing mechanism of a concrete pump in the prior art with reference to Fig. 2, reference numeral 1 designates a slide plate, numeral 2 designates a slide ring, numeral 3 designates an S-shaped gate valve, and the slide ring 2 is mounted to .a tip end portion of the S-shaped gate valve 3.

oo Reference numeral 5 designates a cylinder, and this cylinder 5 supports the S-shaped gate valve 3 so as to be movable in its axial direction and to be swingable about its axis. Reference numeral 4 designates a drive cylinder and this drive cylinder 4 is adapted to swing the S-shaped gate valve 3 about its axis.

Reference numeral 6 designates a piston fixed to 1A the outer circumferential surface of the S-shaped gate valve 3, and between the same piston 6 and the rear end of the cylinder 5 is formed a pressure chamber.

Reference numeral 8 designates a pressurized fluid feed pump, numeral 7 designates a pressurized fluid feed piping extending from a delivery side of the same pressurized fluid feed pump 8 to the pressure chamber behind the above-mentioned piston 6, and numeral 10 designates a safety valve (safety valve having a set pressure of 10 kg/cm 2 connected to the same pressurized fluid feed piping 7 via a tank side piping.

r oo In the above-described S-shaped gate valve pressing mechanism of a concrete pump shown in Fig. 2, pressurized fluid (pressurized fluid at a constant pressure determined by the set pressure of the safety valve delivered from the pressurized fluid feed pump 8 is fed to the pressure chamber behind the piston 6 via the pressurized .fluid feed piping 7 to advance the piston 6, the S-shaped on•• gate valve 3 and the slide ring 2 and press the same slide ring 2 against the slide plate 1, and on the other hand, the S-shaped gate valve 3 is' made to swing about its axis by actuating the drive cylinder 4.

For the above-described S-shaped gate valve 3, the followings are required. That is, it is required that upon swinging (upon switching) of the S-shaped gate valve, -2a necessary minimum pressing force is generated to reduce an amount of abrasion of the slide plate 1 and the slide ring 2. Whereas at the time of forced feeding of concrete after the S-shaped gate valve 3 was switched, in order to minimize leakage of cement paste or the like through the gap space between the slide plate 1 and the slide ring 2, it is required that the gap distance between the slide plate 1 and the slide ring 2 is minimized by generating a pressing force i as large as possible, 10 However, in the S-shaped gate valve pressing mechanism for a concrete pump in the prior art shown in Fig.

2, the slide ring 2 is pressed against the slide plate 1 by feeding pressurized fluid (pressurized fluid having a constant pressure determined by the set pressure of the safety valve 10) delivered from the pressurized fluid feed pump 8 to the pressure chamber behind the piston 6 via the pressurized fluid feed piping 7 to advance the piston 6, the S-shaped gate valve 3 and the slide ring 2. The pressing o force acted upon the slide plate by the slide ring 2 is constant both at the time of swing motion of the S-shaped gate valve 3 and at the time of forced fbeding of concrete after the valve was switched, and so, there was a problem that it cannot fulfil the above-mentioned requirement.

3 4 SUMMARY OF THE INVENTION It is an aim of the present invention to ameliorate one or more problems of the prior art.

It is an advantage that the present invention embodies a control system for an s-shaped gate valve pressing mechanism of a concrete pump, which can inhibit lekage of concrete at the time of forced feeding of concrete and also which can reduce abrasion of a slide plate and a slide ring at the time of swing motion of an s-shaped gate valve.

In an aspect of the present invention there is provided a control system for an s-shaped gate valve pressing mechanism of a pump means with an s-shaped gate valve which has an inlet end portion and an outlet end portion and which is arranged to be swingable about an axis of rotation, the control system comprising; a cylinder; a piston connected to the s-shaped gate valve and being arranged in the cylinder so that a chamber is formed between the piston and an end of the cylinder; a fluid feed pump; first conduit means connecting an outlet side of the S.fluid feed pump to the chamber; S• a high-pressure safety valve arranged in second conduit means which is connected to the first conduit means; and a low-pressure safety valve and a switching valve arranged in third conduit means which is connected to the S3 first conduit means; wherein the piston is driven in the cylinder to cause the inlet end portion of the s-shaped gate valve to be pressed against an outlet side of a slide plate of the S" pump means when fluid under pressure is pumped by said fluid feed pump through the first conduit means into the chamber and wherein the switching valve is arranged so as to be able to switch the low-pressure safety valve between an operable condition and an inoperable condition to thereby regulate the pressure with which the inlet end 4A portion of the s-shaped gate valve is pressed against the outlet side of the slide plate.

Preferably, the piston is connected to an outer circumferential surface of the outlet end portion of the s-shaped gate valve.

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In an embodiment of the present invention, at the time of swing motion of the s-shaped gate valve, the switching valve is transferred to switch the low-pressure safety valve to an operable condition, thereby pressurized fluid at a low-pressure (pressurized fluid at a low pressure determined by a set pressure of the lowpressure safety valve) delivered from the pressurized fluid feed pump is fed through pressurized fluid feed piping to the pressure chamber behind the piston to advance the piston, the s-shaped gate valve and the slide ring, the same slide ring is pressed against the slide plate with a weak force, on the other hand a drive cylinder is actuated to make the s-shaped gate valve swing about its axis, and thereby switching of the sshaped gate valve can be achieved easily. Whereas, at the time of forced feeding of concrete to the s-shaped gate valve, the switching valve is transferred to switch the low-pressure safety valve to an inoperable condition, thereby pressurized fluid at a high pressure (pressurized fluid at a high pressure determined by a set pressure of the high-pressure safety valve) delivered from the pressurized fluid feed pump is fed through the pressurized fluid feed piping to the pressure chamber behind V o ec o S S ego• ooeo o*oooS

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S:09991FA the piston to advance the piston, the S-shaped gate valve and the slide ring, the same slide ring is pressed against the slide plate with a strong force to bring them into tight contact with each other, and thereby leakage of concrete can be minimized.

The above mentioned features and advantages of the present inventio.i will become more apparent by reference to the following description of one preferred embodiment of the o* invention taken in conjunction with the accompanying "10 drawings.

BRIEF DESCRIPTION OF THE DRAWINGS: In the accompanying drawings: too* Fig. 1 is a perspective view showing one preferred 15 embodiment of the control system for an S-shaped gate valve pressing mechanism of a concrete pump according to the present invention; and Fig. 2 is a perspective view. showing one example of a control system for an S-shaped gate valve pressing mechanism of a concrete pump in the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENT: Now the control system for an S-shaped gate valve pressing mechanism of a concrete pump according to the present invention will be described in greater detail in 6 connection to one preferred embodiment thereof illustrated in Fig. 1.

In Fig. 1, reference numeral 1 designates a slide plate, numeral 2 designates a slide ring, numeral 3 designates an S-shaped gate valve, and the slide ring 2 is mounted to the tip end portion of the S-shaped gate valve 3.

Reference numeral 5 designates a cylinder, and this cylinder 5 supports the S-shaped gate valve 3 so as to allow movement in its axial direction and swing motion about :l10 its axis. Reference numeral 4 designates a drive cyl~ider, and this drive cylinder 4 is adapted to make the S-shaped S gate valve 3 swing about its axis.

Reference numeral 6 designates a piston fixed to o an outer circumferential surface of the S-shaped gate valve 3, and a pressure chamber is formed between the same piston 6 and a rear end of the cylinder *Soo Reference numeral 8 designates a pressurized fluid feed pump, ,numeral 7 designates a pressurized fluid feed piping extending from a delivery side of the same pressurized fluid feed pump 8 to the pressure chamber behind the piston 6, numeral 12 designates a piping connecting the same pressurized fluid feed piping 7 and a tank, and numeral 9 designates a high-pressure safety valve (a safety valve having a set pressure of 240 kg/cm 2 provided in the same piping 12.

7 S I Reference numeral 13 designates another piping connecting the above-mentioned pressurized fluid feed piping 7 and a tank, numeral 10 designates a low-pressure safety valve (safety valve having a set pressure of 30 kg/cm 2 provided in the piping 13, and numeral 11 designates an electromagnetic switching valve mounted in the same piping 13 on the side of the tank.

Next, detailed explanation will be made on an Soperation of the control system for an S-shaped gate valve o.

pressing mechanism of a concrete pump shown in Fig. 1 and described above.

At the time of swing motion of the S-shaped gate valve 3, the electromagnetic valve 11 is transferred to switch the low-pressure safety valve 10 to an operable condition, thereby pressurized fluid at a low pressure (pressurized fluid at a low pressure determined by the set pressure of 30 kg/cm 2 of the low-pressure safety valve delivered from the pressurized fluid feed pump 8 is fed through the pressurized fluid feed piping 7 tothe pressure chamber behind the piston 6 to advance the piston 6, the Sshaped gate valve 3 and the slide ring 2, and the same slide ring 2 is pressed against the slide plate 1 with a weak force to reduce friction therebetween, on the other hand the drive cylinder 4 is actuated to make the S-shaped gate valve 3 swing about its axis, and thereby switching of 8 the S-shaped gate valve 3 can be achieved easily.

At the time of forced feeding of concrete, the electromagnetic switching valve 11 is transferred to switch the low-pressure safety valve 10 to an inoperable condition, thereby high-pressure pressurized fluid (pressurized fluid having a high pressure determined by the set pressure of 240 2 kg/cm of the high-pressure safety valve 9) delivered from the pressurized fluid feed pump 8 is fed through the 0 pressurized fluid feed piping 7 to the pressure chamber behind the piston 6 to advance the piston 6, the S-shaped 0 44 gate valve 3 and the slide ring 2, and the same slide ring 2 is pressed against the slide plate 1 with a strong force to bring them into tight contact with each other, and thereby 44 leakage of concrete can be minimized.

15 It is to be noted that the set pressures of the safety valves 9 and 10, respectively, could be automatically varied according to the forced-feeding condition of 44444 concrete.

As will be obvious from the detailed description of one preferred embodiment of the present invention above, the control system for an S-shaped gate valve pressing mechanism of a concrete pump according to the present invention offers the following advantages: That is, at the time of swing motion of an Sshaped gate valve, abrasion of a slide plate and a slide 9 J f t ring can be reduced, because then a swi,...ning valve is transferred to switch the low-pressure safety valve to an operable condition, thereby pressurized fluid at a low pressure (pressurized fluid at a low pressure determined by a set pressure of the low-pressure safety valve) delivered from a pressurized fluid feed puro is fed through a pressurized fluid feed piping to a pressure chamber behind a piston to advance the piston, the S-shaped gate valve and the slide ring, and the slide ring is pressed against the slide plate with a weak force, on the other hand a drive cylinder is actuated to swing the S-shaped gate valve about its axis, and thus switching of the S-shaped gate valve is carried out easily.

Also, at the time of forced feeding ut concrete, 5 leakage of concrete can be minimized, because then the switching valve is transferred to switch the low-pressure safety valve to an inoperable condition, thereby pressurized fluid at a high pressure (pressurized fluid at a high pressure determined by a set pressure of the high-pressure safety valve) delivered from the pressurized fluid feed pump is fed through the pressurized fluid feed piping to the pressure chLmber behind the piston to advance the piston, the S-shaped gate valve and the slide ring, and the slide ring is pressed against the slide plate with a strong force to bring them into tight contact with each other.

10 While a principle of the present invention has been described above in connection to one preferred embodiment of the present invention, it is intended that all matter contained in the above description and illustrated in the accompanying drawings shall be interpreted to be illustrative and not in a limiting sense.

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Claims (9)

1. A control system for an s-shaped gate valve pressing mechanism of a pump means with an s-shaped gate valve which has an inlet end portion and an outlet end portion and which is arranged to be swingable about an axis of rotation, the control system comprising; a cylinder; a piston connected to the s-shaped gate valve and being arranged in the cylinder so that a chamber is formed between the piston and an end of the cylinder; a fluid feed pump; first conduit means connecting an outlet side of the fluid feed pump to the chamber; a high-pressure safety valve arranged in second conduit means which is connected to the first conduit means; and a low-pressure safety valve and a switching valve arranged in third conduit means which is connected to the first conduit means; S 20 wherein the piston is driven in the cylinder to cause the inlet end portion of the s-shaped gate valve to be pressed against an outlet side of a slide plate of the pump means when fluid under pressure is pumped by said fluid feed pump through the first conduit means into the chamber and wherein the switching valve is arranged so as to be able to switch the low-pressure safety valve between an operable condition and an inoperable condition to thereby regulate the pressure with which the inlet end *.*portion of the s-shaped gate valve is pressed against the S 30 outlet side of the slide plate.

2. A control system according to claim 1 wherein the inlet end portion of the s-shaped gate valve is provided with a slide ring and the slide ring is pressed against the slide plate when the fluid under pressure is pumped into the chamber. 13

3. A control system according to claim 1 or 2 wherein the piston is connected to an outer circumferential surface of the outlet end portion of the s-shaped gate valve.

4. A control system according to any one of claims 1 to 3 wherein the switching valve is an electromagnetic switching valve.

A control system according to any one of claims 1 to 4 wherein the switching valve switches the low- pressure safety valve to the operable condition when the s-shaped gate valve is made to swing about the rotational axis.

6. A control system according to any one of claims 1 or 5 wherein the switching valve switches the low- pressure safety valve to the inoperable condition when force feeding of material to the s-shaped gate valve is effected. S:

7. A control system according to any one of claims 1 to 6 wherein the pump means is a concrete pump. 20

8. A contrr' system according to any one of. claims 1 to 7 wherein an outlet end of the second conduit means and an outlet end of the third conduit means are connected to a tank. a

9. A control system for an s-shaped gate valve 25 pressing system of a concrete pump substantially as herein described with reference to figure 1 of the accompanying drawings. Dated this 10th day of August 1994 MITSUBISHI JUKOGYO KABUSHIKI KAISHA By their Patent Attorneys GRIFFITH HACK CO. S:09991FA ABSTRACT A control system for an S-shaped gate valve pressing mechanism is improved so that when concrete is forcibly fed, leakage of concrete may be minimized, while when an S-shaped gate valve is made to swing, abrasion of a slide plate and a slide ring may be reduced. When an S- shaped gate valve 3 is made to swing, an electromagnetic switching valve 11 is actuated to switch a low-pressure a safety valve 10 to an operable condition, thereby pressurized fluid at a low pressure (pressurized fluid at a low pressure determined by a set pressure 30 kg/cm 2 of the low-pressure safety valve 10) delivered from a pressurized fluid feed pump 8 is fed through the pressurized fluid feed piping 7 to a pressure chamber behind a piston 6 to advance the piston 6, the S-shaped gate valve 3 and a slide ring 2, and the same slide ring 2 is pressed against a slide plate 1 with a weak force to reduce friction therebetween, on the other hand the S-shaped gate valve 3 is made to swing about its axis by actuating a drive cylinder 4, and thereby switching of the S-shaped gate valve 3 can be achieved easily. Whereas, at the time of forced feeding of concrete, the electromagnetic switching valve 11 is actuated to switch the low-pressure safety valve 10 to an inoperable condition, thereby pressurized fluid at a high pressure (pressurized t I >Ib I fluid at a high pressure determined by a set pressure 240 2: kg/cm of a high-pressure safety valve 9) delivered from the pressurized fluid feed pump 8 is fed through the pressurized fluid'feed piping 7 to the pressure chamber behind the piston 6 to advance the piston 6, the S-shaped gate valve 3 and the slide ring 2, the same slide ring 2 is pressed against the slide plate 1 with a strong force to bring them into tight contact with each other, and thereby leakage of concrete can be minimized. s a