JPH0674852B2 - Cement-based grout injection device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an injection device for cement-based grout such as a dam.

[Conventional technology]

Unlike chemical grouts that are mainly used for urban civil engineering, dam grouts use cement-based grout materials, usually cement paste, and a return method.

That is, while constantly returning part of the grout fed by the injection pump to the storage tank, the injection pressure and the injection flow rate into the injection pipe are controlled.

In this case, a three-way valve is used because of the need for return. Three-way valves in this type of grout have traditionally been
As shown in JP-A-60-81578, the needle rod is moved back and forth in the axial direction in the valve case, and the degree of advance / retreat is the degree of blockage of the taper portion of the needle rod tip and the inner surface tapered outlet. The amount of return of grout material is controlled by adjusting the.

[Problems to be Solved by the Invention]

However, with this, there is a fundamental problem that the advancing / retreating degree of the needle rod is not linear with respect to the return amount, and therefore within a certain range, the return flow rate greatly changes with a slight advancing / retreating degree. Further, since the grout material is cement-based, the needle rod, in particular, the tapered portion thereof is heavily worn, and the opening degree of the valve changes with each wear, so that the needle rod must be replaced.

Even if the taper portion of the needle rod is made of ceramic, the problem that the return flow rate fluctuates greatly cannot be solved, and the amount of wear is reduced. The cause of this wear is that the principle of sealing is performed by wire, the material is cement-based, and it may be operated at high pressure, so that the wear tends to be more severe. Moreover, the fluctuation of the pressure is large.

Therefore, the present invention is intended to provide an injection device which can linearly change the flow rate balance between the injection system and the return system, and which is extremely easy to control the injection pressure and the flow rate. Another object is to provide a valve body structure with less wear to cement-based grout.

[Means for Solving the Problems]

The above-mentioned problem is a facility for pumping cement-based grout injection material from its storage tank to an injection pipe by an injection pump provided on the way, and one inflow port and two discharge ports are provided between the injection pump and the injection pipe. A diversion valve having is provided, the inflow port of this diversion valve is connected to the injection pump side, one discharge port is connected to the injection pipe side, and the other one discharge port is connected to the return return pipe line connected to the storage tank, An injection pressure detector and an injection flow detector of the grout material are provided between the flow dividing valve and the injection pipe, and the flow dividing valve is a disc-shaped valve body that rotates around an axis in the inner surface cylindrical valve case, And a valve seat fixed in a valve case having two valve seat holes that are in surface contact with the valve body and are independent of each other. The valve body faces the inflow port, And concentric and substantially arcuate within the outer circumference of the disc A through hole, each of the valve seat holes communicates with a corresponding outlet independently of the other, and has an arc shape formed in a circle passing through an arc line of the through hole; The positional relationship between the valve seat hole and each valve seat hole is such that the rotation of the valve body allows selection of a state in which the through hole communicates with only one valve seat hole and a state in which the through hole communicates with both valve seat holes. The problem can be solved by operating the rotating means based on signals from the detector and the flow rate detector to adjust the degree of rotation of the valve body and adjusting the opening degree of the through hole with respect to each valve seat hole. .

[Action]

In the present invention, the valve seat and the valve body are in surface contact with each other, and the opening of the valve seat hole of the valve seat and the through hole of the valve body is adjusted by the rotation of the valve body. It is possible to make a linear proportional relationship with the opening, so that adjustment of the opening,
In other words, it is possible to accurately control the injection pressure and the flow rate, and it is possible to suppress rapid changes in the injection pressure, the return pressure and the flow rate with respect to changes in the opening.

Further, since the valve seat hole of the valve seat and the through hole of the valve body are parallel to the axis, and the valve seat and the valve body are in surface contact with each other, the through hole and the valve seat hole are less worn, and continuous for a long time. It becomes possible to drive.

Moreover, when a high pressure acts, the pressure acting from the inflow port acts on the entire disc-shaped valve body, that is, the entire portion excluding the through hole, and as a result, the valve body is pressed against the valve seat. The higher the level, the higher the sealing performance, and the better the controllability of the return pressure.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, a representative example of the diversion valve A according to the present invention will be described with reference to FIGS. 1 to 4. The diversion valve A is attached to a valve case body 1, a lid plate 2 attached to one side of the valve case body 1 and an other side thereof. In the valve case 4 composed of the divided flow pipe 3, two corresponding arc-shaped valve seat holes 5 and 5'having a smooth surface on one side and being concentric with each other, and the two valve seat holes 5 are provided. 5 ′ has a valve seat 6 provided with two shunt holes 5a, 5′a, which communicate with each other, and a smooth surface in contact with the smooth surface of the valve seat 6, and the valve seat holes 5, 5 A valve element 8 having an arc-shaped through hole 7 corresponding to ′ ′ and having a length longer than the valve seat holes 5 and 5 ′ (the opening is smaller but the length can be shortened). The respective sliding surfaces are placed in contact with each other and housed, and a rotary shaft 9 is attached to which the valve body 8 can be freely rotated in any of left and right directions.

More specifically, the valve seat 6 is fixed by being sandwiched between a projection 1a projecting along the inner circumference of the valve case body 1 and a distribution pipe 3 attached to the valve case body 1 by means such as screwing. The flow dividing tube 3 having the cover plates 3a, 3a attached thereto by means of screwing or the like.
The flow-dividing chambers 10 and 10 'communicating with the flow-dividing holes 5a and 5'a and the discharge ports 11 and 11' communicating with the flow-dividing chambers 10 and 10 'are formed therein. Further, an inflow chamber 12 is formed in the valve case body 1, an inflow port 13 is provided so as to communicate with the inflow chamber 1, and a distal end of a rotary shaft 9 is inserted into a long recess 14 provided in the valve body 8. ing. The rotating shaft 9 has a bearing 15 fitted on the outside thereof,
A nut 16 screwed into the inside of the case body 1 rotatably fixes the position. In addition, 9a is a flange portion protrudingly provided on the outer periphery of the rotating shaft 9, 17 is a loosening prevention bolt screwed through a notch portion 16a provided in parallel to the end surface of the nut 16, and the cover plate 2 is also divided. Like the cylinder, the case body 1 can be screwed or the like.
Installed on.

In the flow dividing valve A having the above-described configuration, a pipe from a storage tank, which will be described later, is provided at the inflow port 13, one discharge port 11 is used as a return pipe line, and the other discharge port is provided.
Connect 11 'to each of the conduits to the injection tube.

The valve body 8 and the rotating shaft 9 are rotated by a drive source (not shown) such as a motor.

The arc-shaped through-holes 7 of the valve body 8 are a plurality of through-holes 7 ″ arranged in an arc shape with a space therebetween, as shown by a broken line in FIG.
It may be 7 ″.

Further, the rotation shaft 9 may be fixed by pressing with a spring fitted on the rotation shaft 9 instead of the bearing 15 and the nut 16. The valve can be made of metal such as stainless steel, but if the valve body and the valve seat are made of ceramics, the durability will be further improved.

In this case, as shown in FIGS. 1 and 3 (B), for example, if a reinforcing plate 8a made of steel, stainless steel or the like is fixed to the valve body by using an adhesive or the like, the valve body will be resistant. It becomes excellent in wear resistance and mechanical strength, and more durable.

The diversion valve A described above is incorporated in the grout injection device described below.

FIG. 4 shows a system diagram of an example of this grout injection control system, in which 18 is a storage tank for storing grout, and the grout in the storage tank 18 is constantly stirred by a stirrer. 19 is a suction pipe line that connects the storage tank 18 and the suction port of the grout pump (injection pump) 20, 21 is the discharge port of the grout pump 20 and the inlet of the valve A
A supply line connecting 13 and a return line 22 for returning the grout discharged from the discharge port 11 of the valve A to the storage tank 18, and an injection line 23 connected to the discharge port 11 'of the valve A for injection. The pipe line 23 is connected to the injection port 24a of the injection pipe 24 in the hole drilled in the ground,
The injection conduit 23 is provided with a flow rate detector 25 and a pressure detector 26, and the controller 27 presets the flow rate and pressure signals detected by the flow rate detector 25 and the pressure detector 26. The flow rate and the set value of the pressure are compared, and the valve A is operated so that the detected value approaches the set value, that is, the rotating shaft 9 and the valve body 8
It is configured to rotate.

In this grout injection control system, when the injection pressure is higher than the sum of the lift due to the pressure loss of the return line 22 and the lift due to the height difference between the inlet 24a and the storage tank 18, the outlet of the valve A is
By setting the opening of the 11'-side flow passage to be larger than the current one, that is, by making the opening of the discharge port 11-side flow passage smaller than the current one, it is possible to control the flow rate and pressure set, and the injection pressure is returned to the return line. If it is lower than the sum of the lift due to the pressure loss of 22 and the lift due to the height difference between the inlet 24a and the storage tank 18, or if the ground injection resistance is low and the amount of grout above the set flow rate is injected by gravity flow, By controlling the opening of the flow passage of the branch valve A on the discharge port 11 'side to be smaller than the current state, that is, making the opening of the flow channel on the discharge port 11 side larger than the current state, the flow rate and pressure of the grout to be injected are controlled to set values. can do.

In some cases, the above two states may alternately appear with the lapse of time from the start of one infusion section to the infusion, but the diversion valve A can immediately respond in any case. Regardless of the injection conditions, it is possible to perform grout injection as specified in the construction specifications.

Further, the valve that has been conventionally used for grout injection is a non-sealing type due to its structure due to wear caused by grout, and therefore, for example, as shown in FIG.
If it is higher than a and the return pressure due to the difference in height is higher than the set injection pressure, even if you try to control to the set pressure,
The actual injection pressure is higher than the set injection pressure and therefore
Can be injected at the set injection pressure unless the return pressure is lowered by moving the
18 had to be moved, the work was inefficient, the construction period was long, and it was extremely uneconomical.

However, when the flow dividing valve A according to the present invention is used, any of the discharge ports can be completely sealed, so that the valve A and the injection port 24a are connected as shown in FIG. 5 and FIG. By providing the accumulator 28 or the air chamber 29 between them, it is possible to perform the grout injection according to the set injection pressure even if the return pressure is higher than the set pressure.

That is, FIG. 5 shows the injection line 23 between the valve A and the injection port 24a.
The case where the accumulator 28 is provided is shown.The accumulator 28 not only buffers the pressure pulsation by the grout pump 20 and smoothes not only the pressure but also the flow rate, and the set injection pressure is lower than the return pressure and is a very small pressure. Even in this case, the grout can be injected at the set injection pressure without moving the storage tank 18 by repeating the slight opening and closing of the discharge port 11 'and buffering the pressure pulsation generated by the repeated opening and closing by the accumulator 28.

Further, FIG. 6 shows a case where an air chamber 29 is provided in the injection conduit 23 between the valve A and the injection port 24a, 30, 30 'are level switches attached to the air chamber 29, and 31 is an air chamber 29. A pressure air source such as a compressor for supplying air through a pipe 32, 33 is a pressure adjusting valve for adjusting pressure air from a pressure air source 31 provided in the pipe 32 to a desired air pressure, 34
Is a pneumatic control valve provided between the pressure control valve 33 of the pipe 32 and the air chamber 29, 35 is a solenoid valve for opening and closing the pneumatic control valve 34, 36 is the pneumatic control valve 34 of the pipe 32 and the air chamber A check valve provided between the air chamber 29 and the control unit 37 when the lower limit level switch 30 'attached to the air chamber 29 is activated.
To the control unit 37 when the upper limit level switch 30 is actuated and the solenoid valve 35 is operated to operate the pneumatic valve 34. Open to supply air. That is, the air in the air chamber is prevented from melting into the grout to reduce the volume, and the volume does not change within a certain range. Like the accumulator, a slight pressure is injected without moving the storage tank. However, compared with the case where an accumulator is provided, it is possible to inject grout by maintaining the air pressure in the air chamber at a desired air pressure and further adjusting the pressure pulsation to a slight pressure.

〔The invention's effect〕

As described above, according to the present invention, the flow rate balance between the injection system and the return system can be changed linearly, and the control of the injection pressure and the flow rate becomes extremely easy. In addition, the shunt valve has less wear than cement-based grout.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an example of a diversion valve, and FIGS. 2 (A) and 2 (B).
(C) is a front view, a longitudinal sectional view and a rear view of an example of a valve seat, and FIGS. 3 (A) and (B) are front views and side sectional views of an example of a valve element, and FIGS. Fig. 7 is a system diagram of an example of a grout injection control system having a slightly different method, and Fig. 7 is a schematic view showing an example of grout injection site construction. 4 ... Valve case, 5,5 '... Valve seat hole, 6 ... Valve seat, 7 ...
… Through hole, 8,8 ′ …… Valve element, 9 …… Rotary shaft, 18 …… Storage tank, 20 …… Grout (injection) pump, 21 …… Supply pipeline,
22 ... Return line, 23 ... Injection line, 24 ... Injection line, 25 ...
… Flow rate detector, 26 …… Pressure detector.

Claims (1)

[Claims] 1. A cement-based grout injection material is stored in a storage tank (1
The injection pipe (2) by the injection pump (20) provided on the way from 8)
4) In a facility for sending pressure to the injection pump (20) and the injection pipe (24), a flow dividing valve having one inflow port (13) and two discharge ports (11), (11 ') (A) is provided, the inflow port (13) of this flow dividing valve (A) is connected to the injection pump (20) side, and one discharge port (11 ') is connected to the injection pipe (24) side. The discharge port (11) is connected to a return return line (22) connected to the storage tank (18), and a grout material injection pressure detector (26) is provided between the diversion valve (A) and the injection pipe (24). An injection flow rate detector (25) is provided, and the flow dividing valve (A) is a disc-shaped valve body (8) that rotates around an axis in a valve case (1) having a cylindrical inner surface, and the valve body ( A valve seat (6) fixed in the valve case (1) having two independent valve seat holes (5) and (5), which are in surface contact with the valve means (8) and the rotating means of (8). ) And The valve body (8) has a through hole (7) facing the inflow port (13) and being concentrically and substantially arcuate in the outer circumference of the disc, and the valve seat holes (5) ) And (5) are connected to the corresponding discharge ports (11) and (11 ') independently of each other, and have an arc shape formed in a circle passing through the arc line of the through hole (7). None, the positional relationship between the through hole (7) and the valve seat holes (5), (5) is such that the rotation of the valve body (8) allows the through hole (7) to communicate with only one valve seat hole. It is possible to select the state in which the valve is opened and the state in which both valve seat holes (5) and (5) are communicated with each other. It operates to adjust the degree of rotation of the valve body (8) to adjust the opening degree of the through hole (7) with respect to the valve seat holes (5) and (5). Cement-based grout injection device that.