JPH0412152Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an earth and sand pumping device for pumping excavated earth and sand using a piston, such as a shield excavator.

[Conventional technology]

The configuration of a conventional earth and sand pumping device is shown in Figures 3 and 4.
This will be explained with reference to the figures.

This conventional earth and sand pumping device has an earth and sand storage tank 1.
and a cylindrical slide tube 3 having an open end and sliding back and forth linearly within the sediment storage tank 1;
An earth and sand pumping piston 2 that reciprocates inside this slide cylinder 3 in the axial direction of the slide cylinder 3, a ring-shaped seal 4 provided at a place where the tip of the slide cylinder 3 of the earth and sand storage tank 1 comes into contact, and the earth and sand The storage tank 1 is provided with a pressure feeding pipe 5 connected to the storage tank 1. The sediment storage tank 1 is integrally provided with a cylindrical seal case 6 that holds a seal 4. The slide tube 3 is reciprocated by a slide tube jack 8. In addition, the earth and sand pumping piston 2
is configured to be reciprocated by a piston jack 7, and has a flange 9 integrally formed at its base end with which the base end of the slide tube 3 engages. The seal 4 is made of metal or urethane rubber, and has a structure in which the slide tube 3 is pressed against the seal 4 to achieve sealing.

Next, we will explain the operation of the conventional earth and sand pumping device described above in a third manner.
This will be explained with reference to the figures.

(a) Extend the slide cylinder jack 8, slide the slide cylinder 3 in the direction of the arrow, and take the earth and sand 10 in the earth and sand storage tank 1 into the slide cylinder 3.

(b) Further extend the slide cylinder jack 8 and press the tip of the slide cylinder 3 against the seal 4 to seal and isolate the inside of the slide cylinder 3 and the inside of the sediment storage tank 1.

(c) Extend the piston jack 7 and slide the earth and sand pumping piston 2 in the direction of the arrow to push out the earth and sand 10 inside the slide cylinder 3 and forcefully feed it into the pressure feeding pipe 5.

(d) Retract the slide tube jack 8 and slide the slide tube 3 back in the direction of the arrow. At this time,
When the base end of the slide tube 3 engages with the flange 9 of the earth and sand pumping piston 2, the earth and sand pumping piston 2 also slides back in the direction of the arrow along with the slide tube 3, and the earth and sand 10 is newly sucked into the earth and sand storage tank 1. It can be done.

Thereafter, the above-mentioned operations (a), (b), (c), and (d) are repeated to force-feed the earth and sand 10 through the pressure-feeding pipe 5.

In this type of earth and sand pumping equipment, the above-mentioned operation is
In step (b), it is important to reliably press the slide tube 3 against the seal 4 to completely isolate the inside of the slide tube 3 and the inside of the earth and sand storage tank 1 in order to forcefully transport the earth and sand 10.

[Problem that the invention attempts to solve]

In the above-mentioned earth and sand pumping device, the earth and sand in the slide cylinder 3 is pumped by the earth and sand pumping piston 2 from a state in which the slide tube 3 is extended and the pressure pipe 5 and the sediment storage tank 1 are isolated (the state shown in FIG. 3B). While reaching the state of pushing out to the pipe 5 (the state shown in Fig. 3 C), the internal pressure of the slide cylinder 3 and the pressure-feeding pipe 5 rises by the pressure-feeding load, and at this time, this pressure also acts on the tip 3a of the slide cylinder 3. I will do it. To explain this in detail with reference to FIG. 4, when the earth and sand are pumped, a pressure commensurate with the load is generated inside the slide cylinder 3 and the pressure pipe 5, but the pressure P
also acts between the tip 3a of the slide tube 3 and the seal 4 inside the seal case 6, and tries to push the slide tube 3 back. Particularly, as shown in FIG. 5, when the abutting surfaces of the tip 3a of the slide cylinder 3 and the seal 4 are tapered, the pushing back force becomes even greater. When the slide tube 3 is pushed back against the push-back force, a gap is created between the slide tube 3a and the seal 4, and earth and sand leak from the gap, reducing the pumping efficiency. In addition, the slide cylinder tip 3a and the seal 4 are worn out by the earth and sand flowing out from the gap, and the gap gradually becomes larger, and eventually the balance with the pumping load is lost, and the entire amount of earth and sand in the slide cylinder 3 flows out from the gap.
This will result in the inability to pump.

An object of the present invention is to provide an earth and sand pumping device that has a simple configuration and can prevent the slide tube from being pushed back due to the pumping load during earth and sand pumping.

[Means for solving problems]

In order to achieve the above object, the present invention provides a means for completely closing the hydraulic oil return flow path on the bottom side of the slide cylinder jack when the slide cylinder jack stops operating. After the pressure accumulating means is provided and the limit switch that detects the end of the earth and sand intake process is operated, the pressure accumulating means is activated until the hydraulic pressure switching valve of the slide cylinder jack stops supplying hydraulic oil to the bottom side of the slide cylinder jack. A timed operation element is provided to provide a sufficient time delay for pressure to accumulate, and a force is generated in the slide cylinder jack as hydraulic pressure to counter the push-back force acting on the tip of the slide cylinder due to the pumping load during the earth and sand pumping process. It is characterized by

[Effect]

At the end of the earth and sand intake process, the hydraulic switching valve is operated based on the signal from the limit switch that detects this to stop the supply of hydraulic oil to the bottom side of the slide cylinder jack. The pressure is accumulated in the pressure accumulating means due to the time delay,
After stopping the supply of hydraulic oil, completely close the hydraulic oil return passage on the bottom side of the slide cylinder jack. As a result, during the earth and sand pumping process, a force is generated in the slide cylinder jack as hydraulic pressure that counters the push-back force exerted on the tip of the slide cylinder due to the pumping load, and the hydraulic pressure is used to prevent the slide cylinder from being pushed back. It is.

[Example] Fig. 1 shows a hydraulic circuit according to an embodiment of the present invention.
The figure shows the electrical circuit.

In FIG. 1, 11 is a hydraulic switching valve for the slide cylinder jack 8, and 12 is a hydraulic switching valve for the piston jack 7. The hydraulic switching valve 11 is an electromagnetically operated 4-port switching valve in which all ports are closed in the neutral position.The A port is connected to the hydraulic oil return passage 8a on the bottom side of the slide cylinder jack 8, and the B port is connected to the slide cylinder jack 8. The hydraulic switching valve 12 is an electromagnetically operated two-port switching valve, and its A port is connected to the hydraulic oil line return path 8b on the rod side of the piston jack 8. It is connected to the return flow path 7a.

13 is when the slide cylinder jack 8 stops operating;
This is a pilot operated check valve provided to completely close the hydraulic oil line return passage 8a on the bottom side, and when the slide tube 3 slides back as shown in FIG. The valve is opened by the pilot pressure from the valve, and the hydraulic oil on the bottom side can be returned. 14 is the jack 8 for the slide tube
and the bottom side of the pilot operated check valve 13.
This is a pressure accumulator installed in the hydraulic oil line return flow path 8a between the slide tube and the slide tube, and is shown as an example of a pressure accumulator that accumulates pressure on the bottom side of the slide cylinder jack 8 at the end of the earth and sand intake process. .

In this embodiment, in order to simplify the device, a hydraulic unit consisting of a relief valve 15, a hydraulic pump 16, and an oil tank 17 is shared by the piston jack 7 and the slide cylinder jack 8, and the hydraulic switching valve 11
The P port of the hydraulic switching valve 12 and the P port of the hydraulic switching valve 12 are connected to the hydraulic pressure supply side of the hydraulic unit, and the hydraulic switching valve 1
A hydraulic circuit is constructed by connecting the R port of No. 1 and the rod side of the piston jack 7 to the drain return side of the hydraulic unit.

The switching valve operating means is a hydraulic switching valve 1 shown in FIG.
1, operating solenoids a and 12, relays SC, SN, AN, and limit switches 18, 19, and 20. In Figure 2, 2
1, 22, 23 are coils of relays SC, SN, AN,
24, 25, 26 are normally open contacts of relays SC, SN, AN, 27, 28, 29 are relays SC, SN, AN
normally closed contacts, 30, 31, 32 are relays SC,
This is a self-holding contact for SN and AN. Here, SN is a timed relay having on-delay contacts 26 and 27, and is provided as a timed operating element operated by an input signal from the limit switch 20. Limit switches 18, 19, 20 are
As shown in FIG. 3, the limit switch 18 is turned on when the slide cylinder 3 is in the backward position, the limit switch 20 is turned on when the slide cylinder 3 is in the forward position, and the limit switch 19 is turned on when the earth and sand pumping piston 2 is in the forward position. Placed.

In this embodiment, P ₁ is the working hydraulic pressure of the piston jack 7 during the pumping process [Kg/cm ² ], P ₂ is the working hydraulic pressure of the slide cylinder jack 8 during the pumping process [Kg/cm ² ],
A _M is the pressure receiving area on the bottom side of the piston jack 7 [cm ² ], A _P is the pressure receiving area of the earth and sand pumping piston 2 [cm ² ], A _D is the pressure receiving area of the slide cylinder tip 3a [cm ² ], A _S When is the pressure receiving area on the bottom side of the slide cylinder jack 8 [cm ² ], N _M is the number of piston jacks 7 [pieces], and N _S is the number of slide cylinder jacks 8 [pieces], the following (1) is obtained. The above specifications are selected so that the relationship in the formula holds true.

N _M ×P ₁ ×A _M /A _P ×A _D ≦N _S ×P ₂ ×A _S ...(1) In the above equation, the left side represents the push-back force acting on the slide cylinder tip 3a due to the pumping load during the pumping process. ,
The right side represents the hydraulic pressure generated in the slide cylinder jack 8 during the pressure feeding process.

Next, the operation of the earth and sand pumping device in this embodiment will be explained with reference to FIGS. 1, 2, and 3.

() Sediment intake process: When the slide cylinder 3 is fully compressed, the limit switch 18 is turned on, and the coil 21 of the relay SC is energized to self-hold.
When the normally open contact 24 of the relay SC is turned on, the solenoid a of the hydraulic switching valve 11 is energized and the A port of the hydraulic switching valve 11 is connected to the P port and the B port is connected to the R port. Pressure oil flows into the bottom side. As a result, the slide tube 3 moves forward, and the sediment storage tank 1
The soil inside is taken into the slide tube 3.

() Earth and sand pumping process: At the end of the earth and sand intake process, the limit switch 20 is turned on and the relay SN is turned on.
The coil 22 of the relay SN is energized and self-held, but since the normally open contact 26 and the normally closed contact 27 of the relay SN are on-delay contacts, the contact 26 turns on after an arbitrary set time (about 0.1 to 0.5 seconds) has elapsed.
Contact point 27 is turned off. During this time delay, hydraulic oil continues to be supplied to the bottom side of the slide cylinder jack 8 through the hydraulic switching valve 11 and the pilot operation check valve 13. However, since the slide tube tip 3a is in contact with the seal 4 at the same time as the slide tube 3 reaches its stroke end (extension limit), the oil pressure on the bottom side of the slide tube jack 8 is reduced to the set pressure of the relief valve 15 (maximum). The pressure increases to the working pressure) and is stored in the pressure accumulator 14. Thereafter, as the normally closed contact 27 is turned off, the normally open contact 24 of the relay 21 is also turned off, so the hydraulic switching valve 11 is placed in the neutral position and the supply of hydraulic oil to the slide cylinder jack 8 is stopped. On the other hand, when the normally open contact 26 is turned on, the solenoid a of the hydraulic switching valve 12 is energized, and in order to connect the A port and the P port of the hydraulic switching valve 12, pressure oil is supplied to the bottom side of the piston jack 7. The flow advances the earth and sand pumping piston 2 and moves on to the earth and sand pumping process, but even after the supply of hydraulic oil through the hydraulic switching valve 11 is stopped, the pilot operation check valve 13 is operated by the pressure accumulator 14.
Hydraulic pressure corresponding to the set pressure of the relief valve 15 remains on the bottom side of the slide cylinder jack 8, and the slide cylinder 3 is moved to the seal 4 by this hydraulic pressure.
It will be pushed to the side. During the pressure feeding process, the relationship of equation (1) is always satisfied, so if a large amount of hose is used in the hydraulic oil return passage 8a on the bottom side of the slide cylinder jack 8, the hose Due to the bulge, the slide tube 3 is prevented from being pushed back by the pushing back force of the pumping load, and the hydraulic pressure presses the slide tube tip 3a against the seal 4, thereby sealing the inside of the slide tube 3 and the inside of the sediment storage tank 1. Can be completely sealed and isolated.

() Suction process: When the earth and sand pumping piston 2 moves forward and reaches the position where it completes pushing out the earth and sand in the slide cylinder 3, the limit switch 19 is turned on, and the coil 23 of the relay AN is energized to self-hold. By turning off the normally open contact 28 of relay AN, the normally open contact 26 of relay SN
Since the solenoid a of the hydraulic switching valve 12 is also turned off, the solenoid a of the hydraulic switching valve 12 becomes non-energized, and the flow of pressure oil to the bottom side of the piston jack 7 is stopped. At the same time, the normally open contact 25 of the relay AN is turned on, so that the solenoid b of the hydraulic switching valve 11 is energized, and the A port of the hydraulic switching valve 11 is changed to the R port.
In order to communicate the B port with the P port, pressure oil flows into the rod side of the slide jack 8, and the pilot operation check valve 13 is opened by the pilot pressure from the rod side hydraulic oil line return passage 8b. Slide back. At this time, the base end of the slide cylinder 3 is connected to the earth and sand pumping piston 2.
The earth and sand pumping piston 2 is also slid back at the same time.

Thereafter, the above operations (), (), () are repeated to pump the earth and sand.

In this embodiment, a pilot operated check valve 13 is used as a means for fully closing the bottom side hydraulic oil return passage 8a when the slide cylinder jack 8 stops operating.
However, any valve may be used as long as it performs the same function (for example, instead of using a pilot-operated check valve, the hydraulic switching valve 11 may be a non-leak valve without internal leakage). Alternatively, instead of using the special pressure accumulator 14 as the pressure accumulating means, a pressure accumulating function by the bulges of hoses used in the hydraulic oil line return passage 8a may be used.

[Effect of idea]

According to the present invention, a force that counters the push-back force exerted on the tip of the slide cylinder due to the pressure-feeding load during the pressure-feeding process is generated in the slide cylinder jack as hydraulic pressure, and the hydraulic force can prevent the slide cylinder from being pushed back. Therefore, during the pumping process, the inside of the slide cylinder and the inside of the sediment storage tank are completely sealed and isolated, and the pumping efficiency of the sand can be maintained at a good level. Moreover, since no separate mechanism such as a mechanical stopper for holding the slide tube in the forward position is required, the device can be constructed simply and at low cost.

[Brief explanation of the drawing]

Figure 1 is a hydraulic circuit diagram of one embodiment of the present invention, Figure 2 is a hydraulic circuit diagram of an embodiment of the present invention.
The figure shows the same electric circuit, Figure 3 is an explanatory diagram of the operation of the earth and sand pumping device, and Figure 4 is an enlarged view showing an example of part S in Figure 3.
FIG. 5 is an enlarged view showing another example of the section S in FIG. 3. 1... Sediment collection tank, 2... Sediment pressure feeding piston, 3... Slide tube, 4... Seal, 5... Pressure feeding pipe, 7... Piston jack, 8... Slide tube jack, 8a... Slide Hydraulic oil line return passage on the bottom side of the cylinder jack, 11... Hydraulic pressure switching valve of the slide cylinder jack, 13... Pilot operation check valve (means for fully closing the hydraulic oil line return passage 8a), 14 ...Pressure accumulator (pressure accumulating means),
20...Limit switch that detects the end of the earth and sand intake process, SN...Timed relay (timed operation element), 2
6, 27...On-delay contact.

Claims (1)

[Scope of utility model registration request] a sediment storage tank; a slide tube having an open end and sliding back and forth linearly within the sediment storage tank;
An earth and sand pumping piston that reciprocates in the axial direction of the slide cylinder, a slide cylinder jack that reciprocates the slide cylinder in the axial direction, a piston jack that reciprocates the earth and sand pumping piston in the axial direction, and earth and sand. A pressure feeding pipe connected to a storage tank is provided, the slide cylinder is slid forward to take in earth and sand into the slide cylinder, the inside of the slide cylinder and the inside of the sediment storage tank are sealed and isolated, and the earth and sand pressure piston is slid forward. In an earth and sand pumping device that pushes out earth and sand in a slide cylinder and pumps it into a pressure pipe, a means is provided for completely closing a hydraulic oil return passage on the bottom side of a slide cylinder jack when the slide cylinder jack stops operating. A pressure accumulating means is provided in the hydraulic oil line return flow path, and after the limit switch is activated to detect the end of the earth and sand intake process, the hydraulic switching valve of the slide cylinder jack controls the flow of hydraulic oil to the bottom side of the slide cylinder jack. A timed operation element is provided to provide a sufficient time delay for pressure to accumulate in the pressure accumulating means before the supply is stopped, and a force is applied to the slide cylinder jack to counter the push-back force exerted on the tip of the slide cylinder by the pumping load during the earth and sand pumping process. An earth and sand pumping device characterized by generating hydraulic pressure.