JPH04292581A - Forced feed pump of sediment or the like - Google Patents

Abstract

PURPOSE:To prevent danger due to blow-out in a secure manner by providing a return line on the downstream side of a changeover valve with a line resistance part to generate a back pressure to shift the sliding cylinders automatically to the position of the shut-off condition of an earth/sand storing part and a forced feed pipe between both chambers of respective hydraulic jacks for sliding cylinders when a forced feed pump is stopped. CONSTITUTION:A means is provided which is connected to respective hydraulic jacks 13a, 13b, 14 and switches expansion/contraction of the hydraulic jacks and a means which is interlocked with a forced feed pump and communicates a chamber on the bottom side with a chamber on the rod side of the respective hydraulic jacks 13a, 13b, 14, and at the same time, makes communication with an oil tank 26 when the forced feed pump is stopped. A return line of the hydraulic jacks for sliding cylinders is provided with a line resistance part 24 to generate a back pressure to shift the sliding cylinders automatically to the position of the shut-off condition of an earth/sand storing part and a forced feed pipe between both chambers of the respective hydraulic jacks for sliding cylinders when forced feed pump is stopped.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a pump that pumps earth and sand in an earth and sand storage section through a pressure transfer pipe for discharging soil connected to the earth and sand storage section by a piston driven by hydraulic pressure, and particularly relates to a pressure pump. The present invention relates to a pump suitable for automatically shutting off the flow of earth and sand between the earth and sand reservoir and the pressure transfer pipe when the hydraulically driven power source is turned off.

0002

[Prior Art] A pressure pump for transporting earth and sand (hereinafter simply referred to as a pressure pump) is used to transport earth and sand accumulated in a sand storage tank or hopper in a tunnel or mine over a relatively long distance via a pressure pipe. It is often used for transportation. The sediment that has accumulated in the sediment storage area may be affected by spring water or pressure in the tunnel, or may be affected by pressure that tries to flow back from the pressure pipe side. In the former case, the pressure In the latter case, there is a risk that earth and sand will erupt from the pipe outlet in the earth and sand reservoir.

A specific example of using a conventional pressure pump in a shield excavator will be described with reference to FIGS. 2 and 3. FIG. 2 is a longitudinal sectional view showing an example of a shield excavator equipped with a pressure pump, and FIG. 3 is a sectional view taken along line III--III in FIG. In the figure, 1 is the shield body, 2 is a cutter foil that excavates the earth 3, 4 is a screw conveyor that transfers the excavated earth and sand to the rear,
Reference numeral 4a denotes an earth and sand discharge port provided on the screw conveyor 4, and 5 denotes an earth and sand storage tank for storing earth and sand discharged from the discharge port 4a, which is attached to the discharge port 4a. The earth and sand storage tank 5 has opposing walls 5a and 5b, and the wall 5a
is provided with an opening 5c, to which a pressure pipe 6 for pumping earth and sand is connected and a seal 7 is attached. On the other hand, a hole 5d that is concentric with the opening 5c and has approximately the same diameter is provided in the wall 5b. 8 fits into the hole 5d and the hole 5d
A slide tube that moves between the walls 5a and 5b using as a guide,
The tip of the slide tube 8 reaches the surface of the wall 5a and the seal 7 moves.
When pressed, the inside of the slide cylinder 8 and the pressure-feeding pipe 6 are brought into communication, and the flow of earth and sand between the inside of the earth and sand storage tank 5 and the pressure-feeding pipe 6 is cut off. 9 is a piston that slides inside the slide tube 8; 10 is its piston rod; 11 is a flange having a larger diameter than the piston rod 10 fixed to the base end side of the piston rod 10; and 12 is a rod that projects from the flange 11. It is. Reference numerals 13a and 13b are two hydraulic jacks that hydraulically drive the slide tube 8, and are connected to both sides of the rear end of the slide tube 8, respectively. A hydraulic jack 14 hydraulically drives the piston 9, piston rod 10, etc., and is connected to the base end of the piston rod 10. The hydraulic jacks 13a, 13b, and 14 are all attached to the frame 15, with the hydraulic jack 14 in the center and the hydraulic jacks 13a, 13b arranged on both sides thereof. Reference numerals 16, 17, and 18 are switches for position detection; the switch 16 detects the backward end of the slide tube 8, the switch 17 detects the forward end of the slide tube 8, and the switch 18 detects the forward end of the piston 9. Hydraulic jacks 13a, 13b,
14 stop and expansion/contraction switching signals.

When a push button switch (not shown) for operating the pressure pump of the above configuration is operated from the position where the slide cylinder 8 and piston 9 shown in FIG. 13a, 13b, the slide cylinder 8 is advanced and the tip is sealed with the seal 7.
At the pressed position, the switch 17 operates to cut off the supply of pressure oil and stop the slide cylinder 8. (Status shown in Figure 3(b))
When this state is maintained and pressure oil is supplied to the bottom side of the hydraulic jack 14 to move the piston 9 forward as shown in FIG. When the flange 11 comes into contact with the rear end surface of the slide tube 8, the switch 18 is actuated by the rod 12, cutting off the supply of pressure oil and stopping the piston 9. At the same time as the piston 9 stops, pressurized oil is supplied to the rod sides of the hydraulic jacks 13a, 13b by a switching valve (not shown) to move the slide tube 8 backward. Then, in conjunction with the backward movement of the slide cylinder 8, the piston 9 is also moved backward (the state shown in FIG. 3(d)). When the slide tube 8 and the piston 9 return to the reverse end position shown in FIG. 3(a), the earth and sand storage tank 5 is again filled with earth and sand, and the above-mentioned operations are sequentially repeated to pump the earth and sand.

By the way, the earth and sand excavated by the shield excavator is transferred by the screw conveyor 4 while adjusting the transfer amount so as not to loosen the ground, but the earth may contain spring water or soft soil like sludge. There may be conditions where the soil cannot stand on its own, such as when it contains a large amount of water, and in such cases, water channels are formed within the soil of the screw conveyor 4, soil storage tank 5, and pressure pipe 6, and the soil is contained in the soil due to groundwater pressure or earth pressure at the face. The spring water and soft soil that are present may erupt from the joints of the pressure pipe 6 or from the soil discharge port. Such outbursts of spring water can cause dangerous ground subsidence of the rock face and the filling of constructed tunnels with earth and sand. Therefore, when finishing excavation work or stopping the pressure pump when assembling segments, the operator must always move the slide cylinder 8 forward.
It is specified that the earth and sand storage tank 5 and the pressure-feeding pipe 6 should be cut off to prevent the above-mentioned eruption. However, since the pressure pump is stopped frequently, it is quite troublesome to perform the above operations every time the pump is stopped, and it is also difficult to check the operation each time because the operation may be forgotten due to other tasks. However, there was a problem in that the dangerous situation could not be reliably prevented.

[0006]

[Problems to be Solved by the Invention] As mentioned above, in order to prevent the eruption of spring water, sand, etc. after the pressure pump when the pressure pump is stopped, the conventional pressure pump for discharging sediment, etc., is operated by the operator to pump the sediment into the sand reservoir. However, it is difficult to confirm the operation each time because the operation is frequent and troublesome, and it is easy to forget the operation, so it is not possible to reliably prevent the dangerous situation caused by the above-mentioned eruption. It had some problems.

[0007] The present invention solves the above-mentioned problems of the prior art, and when the pressure pump is stopped, the flow of earth and sand between the earth and sand reservoir and the pressure pipe is automatically cut off, and the flow due to the above-mentioned eruption is automatically interrupted. The purpose of the present invention is to provide a pump for discharging earth and sand, etc., which can reliably prevent danger in advance.

[0008]

[Means for Solving the Problems] The present invention provides an earth and sand reservoir having opposing wall surfaces in which a pressure pipe is connected to one wall and a hole concentric with the pressure pipe is provided in the other wall, and Earth and sand, etc., comprising a slide cylinder that is moved by a hydraulic jack between opposing walls of a dirt storage part, and a piston that is slid within the slide cylinder by a hydraulic jack and that forces the earth and sand in the slide cylinder to a pressure delivery pipe. In the pressure pump, the pressure pump is connected to each of the hydraulic jacks, and the hydraulic jack is extended and retracted, and when the pressure pump is stopped, the bottom side and rod side chambers of each hydraulic jack are communicated with each other, and at the same time, the oil tank is also communicated with the pressure pump. A valve is provided in the return pipe on the downstream side of the switching valve to apply back pressure to the slide cylinder hydraulic pressure to automatically move the slide cylinder to a position where the sediment reservoir and the pressure pipe are cut off when the pressure pump is stopped. The earth and sand pressure pump is characterized by having a conduit resistance section between both chambers of the jack, so that when the pressure pump is stopped, the earth and sand between the earth and sand storage section and the discharge pipe are removed. This system automatically shuts off the flow of soil, etc., and makes it possible to reliably prevent danger from eruption of soil, etc. in the soil discharge line.

[0009]

[Operation] When the pressure pump is stopped, the switching valve is automatically operated so that the bottom side and rod side chambers of each hydraulic jack of the pressure pump are communicated with each other and the oil tank is also communicated with the chambers. For this reason, back pressure acts on both the bottom side and rod side chambers of each hydraulic jack, creating a difference in cylinder force due to the difference in effective cross-sectional area for both chambers, and due to the difference in cylinder force, the hydraulic jack extends until it reaches the wall to which the pressure pipe of the earth and sand reservoir is connected, blocking the flow of earth and sand between the inside of the earth and sand reservoir and the discharge pipe. In this case, the back pressure between the two chambers of the hydraulic jack is such that when the pressure pump is stopped, a differential pressure is generated that automatically moves the slide tube to the blocked position between the earth and sand reservoir and the discharge pipe. It is adjusted by providing a conduit resistance section. Therefore, simply by turning off the hydraulic drive power to the pressure pump and stopping the supply of pressure oil, the slide tube automatically moves forward and blocks the flow of dirt, etc. between the dirt reservoir and the discharge pipe. to reliably prevent the eruption of earth and sand in the earth and sand discharge line.

0010

Embodiment An embodiment of the present invention will be described with reference to FIG. 1 and the above-mentioned FIG. 3. FIG. 1 is a hydraulic circuit diagram of a pressure pump. In the figure, the same reference numerals as in FIG. 3 indicate the same things. In the figure, 20 is a hydraulic pump driven by an electric motor 21, 22 is a manifold containing a plurality of switching valves for switching the extension and contraction of the hydraulic jacks 13a and 13b, and 23 is a plurality of switching valves for switching the extension and contraction of the hydraulic jack 14. A manifold with a built-in switching valve, 24 is each hydraulic jack 13a, 13b, 14
A variable throttle valve is used in this embodiment as a pipe resistance section that is provided downstream of the manifolds 22 and 23 of the return pipe and regulates the flow rate thereof. 25 is a relief valve, 2
6 is an oil tank. The manifold 22 has an ABR-connected solenoid pilot switching valve (hereinafter simply referred to as a solenoid valve) 30 and four pilot-operated logic valves 31, 32, 33, and 34 that open and close according to the switching of the solenoid valve 30. , the logic valves 31, 32, 33, and 34 are all open when the solenoid valve 30 is in the neutral position. On the other hand, the manifold 23 has a two-position solenoid pilot switching valve (hereinafter simply referred to as a solenoid valve) 40 and a pilot-operated logic valve 41 that opens and closes depending on the switching of the solenoid valve 40, and the solenoid valve 40 is in the demagnetized position. At this time, the logic valve 41 is open.

When the switch 16 detects the backward movement end position of the slide cylinder 8 and piston 9 shown in FIG. The supplied pressure oil is supplied to the bottom sides of the hydraulic jacks 13a, 13b via the open logic valve 31, and moves the slide cylinder 8 forward. At this time, the solenoid valve 40 is demagnetized and located on the b side, and the logic valve 4
1 is in the open state, the oil on the rod side of the hydraulic jacks 13a, 13b flows into the oil tank 26 via the logic valve 34 in the open state and the logic valve 41 in the open state. In the state shown in FIG. 3(b) in which the tip of the slide tube 8 presses the seal 7, the switch 17 operates and its detection signal causes the solenoid valve 30 to
When the is switched to the neutral position, the supply of pilot pressure oil is stopped, and each logic valve 31, 32, 33, 34 is opened, and pressure oil from the hydraulic pump 20 is sent to the manifold 23 via each logic valve. . At this time, the solenoid valve 40 is switched to the a side by the detection signal of the switch 17 and the logic valve 41 is closed, so the pressure oil sent to the manifold 23 is supplied to the bottom side of the hydraulic jack 14 and the piston 9 is moved forward, and the earth and sand filled in the slide cylinder 8 is pushed out to the pressure pipe 6. and piston 9
The flange 11 shown in FIG. 3(c) comes into contact with the rear end surface of the slide tube 8, and at the same time, the rod 12 moves forward to a position where the switch 18 is activated. On the other hand, while the piston 9 is pushing out the earth and sand in the slide cylinder 8, the hydraulic jack 13a,
Pressure oil from the hydraulic pump 20 is also acting on the bottom side and the rod side of 13b, and the slide tube 8 is moved from the bottom side where the cylinder force is large due to the difference in effective cross-sectional area for both chambers on the bottom side and rod side. The tip is strongly pressed against the seal 7. When the switch 18 is activated in the state shown in Figure (c), the solenoid valve 40 is demagnetized and switched to the b side, and the solenoid valve 30 is switched to the b side. , 41 are open. Pressure oil from the hydraulic pump 20 is delivered to the hydraulic jack 13a via the logic valve 33.
It is sent to the rod side of 13b and moves the slide cylinder 8 backward. At this time, the oil on the bottom side of the hydraulic jacks 13a, 13b flows to the oil tank 26 via the logic valves 32, 41, and the rod side of the hydraulic jack 14 sucks up oil from the oil tank 26 to prevent negative pressure. When the slide tube 8 and the piston 9 return to the state shown in FIG. 3(a) after passing through the state shown in FIG. be pumped.

When stopping the pressure pump for segment assembly, etc., each logic valve 31, 32, 33, 34, 41
When the pilot pressure oil supply is stopped, each solenoid valve 3
0 and 40 are in the demagnetized position and are open, and back pressure acts on the bottom side and rod side of each hydraulic jack 13a, 13b, 14. The back pressure acting on both the bottom side and rod side chambers causes a difference in cylinder force due to the difference in effective cross-sectional area for both chambers, and this difference causes each hydraulic jack 13a, 13b to
, 14 are expanded. This extension is carried out by the hydraulic jack 13a,
The tip of the slide tube 8 connected to the slide tube 13b is moved to a position where it presses the seal 7, and the gap between the earth and sand storage tank 5 and the pressure-feeding pipe 6 is cut off so that the earth and sand cannot flow. In this case, the seal 7 has the effect of improving the blocking performance. The back pressure acting on each hydraulic jack 13a, 13b, 14 causes the tip of the slide tube 8 to automatically extend to a state where the gap between the earth and sand storage tank 5 and the pressure pipe 6 is cut off when the pressure pump is stopped. The variable throttle valve 24 is configured to generate a differential pressure of
adjusted by. The operation of the pressure pump when the operator stops the pressure pump is shown in Figure 3 (
Since any of the steps a) to (d) is performed automatically, a state in which the blowout of earth and sand, etc. is prevented can be reliably and easily obtained when the pressure pump is stopped with only one operation by the operator. . Therefore, there is an effect that repair or replacement work for the pressure pipe 6 and subsequent parts can be carried out safely.

In the above embodiment, the back pressure in the hydraulic jack was adjusted using the variable throttle valve 24, but the slide tube 8 was If a shutoff state is possible, the variable throttle valve 24 may not be provided, and if there is no need to adjust the flow rate to be regulated, a simple throttle valve may be used.

Furthermore, the operator stops the pressure pump (
After signal 1), it may be confirmed by switch 17 that the slide cylinder has extended (signal 2), and the electric motor may be stopped with signals 1 and 2.

[0015]

As explained above, the present invention provides a switching valve that applies back pressure to both chambers on the bottom side and the rod side of the hydraulic jack of the pressure pump when the operator stops the pressure pump, and Since the pressure differential between the two chambers is provided with a pipe resistance section that automatically extends the slide tube so as to cut off the connection between the earth and sand reservoir section and the pressure-feeding pipe, the pressure-feeding pump can be brought into the rest state. When this happens, the flow of earth and sand between the earth and sand reservoir and the pressure transfer pipe is automatically interrupted, which has the practical effect of reliably preventing danger from blowing out earth and sand in the earth and sand discharge line.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a hydraulic circuit for explaining an embodiment of a pump for discharging earth and sand according to the present invention.

FIG. 2 is a diagram showing an example in which a conventional pressure pump is used in a shield excavator.

FIG. 3 is a sectional view taken along line III-III in FIG. 2, and is an explanatory diagram of the configuration and operation of the pressure pump.

[Explanation of symbols]

5... Earth and sand storage tank, 6... Pressure feeding pipe, 8... Slide tube, 9... Piston, 13a, 13b, 14... Hydraulic jack, 20... Hydraulic pump, 22, 23... Manifold, 24
...Pipe resistance part (variable throttle valve), 26...Oil tank, 30...
Solenoid pilot switching valve (solenoid valve), 31, 32, 33,
34...Logic valve, 40...2-position electromagnetic pilot switching valve (electromagnetic valve), 41...Logic valve.

Claims (3)

[Claims] Claim 1: An earth and sand reservoir having opposing wall surfaces with a pressure pipe connected to one wall and a hole concentric with the pressure pipe on the other wall, and an opposing wall surface of the earth and sand reservoir that fits into the hole. A pump for pumping earth and sand, etc., comprising a slide cylinder that is moved by a hydraulic jack between the cylinders, and a piston that is slid within the slide cylinder by a hydraulic jack and that pumps the earth and sand in the slide cylinder to a pressure pipe. A means connected to each jack to switch the expansion and contraction of the hydraulic jack, and a means that communicates both the bottom side and rod side chambers of each hydraulic jack when the pressure pump is stopped, and also communicates with the oil tank at the same time. and a pipe line resistance section that generates back pressure between both chambers of the hydraulic jack for the slide tube to automatically move the slide tube to a position where the earth and sand reservoir section and the pressure feed pipe are cut off when the pressure pump is stopped. A pump for pumping earth and sand, characterized in that it is provided in a return line of the hydraulic jack for the slide cylinder. 2. The switching valve is an electromagnetic pilot switching valve that operates in conjunction with a switch for detecting the moving end position of the slide cylinder and the piston, and an open position when the electromagnetic pilot switching valve is switched to a demagnetized position. A pressure-feeding pump for earth and sand, etc., according to claim 1, which is configured in combination with a logic valve. 3. The earth and sand pressure pump according to claim 1, wherein the pipe resistance section is constituted by a variable throttle valve.