JPH0381580A - Pump for forced feed of ready-mixed concrete - Google Patents

Abstract

PURPOSE:To enable the continuous and smooth feed of ready-mixed concrete under pressure without causing the biting of an aggregate by making one surface of the valve body of a three-way open/close valve like a circular arc form, and constituting the body as a rotary valve of crescent section having a sharp part at both ends thereof. CONSTITUTION:Valve bodies 21a and 21b constituting a three-way open/close valve having one surface formed like a circular arc and a crescent sectional form with a sharp part at both ends are so provided as be freely rotatable in valve boxes 2a and 2b under the bottom outlet 1a of a hopper 1. Valve cylinders 5a and 5b are provided at the sides of the valve boxes 2a and 2b, and the rods 6a and 6b of the valve cylinders 5a and 5b are connected to support shafts 22a and 22b via support levers 7a and 7b. Due to the telescopic motion of the rods 6a and 6b, therefore, the support shafts 22a and 22b turn, thereby causing the open and close operation of the valve bodies 21a and 21b constituting the three-way open/close valve.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. The present invention is a method for pumping fresh concrete that continuously pumps fresh concrete by causing a cylinder device consisting of a concrete cylinder and a hydraulic cylinder to alternately suck and discharge the fresh concrete. This invention relates to the structure of a switching section between suction and discharge of fresh concrete in a commercial pump.

Ready-mixed concrete is indispensable for carrying out construction work, and with the diversification of construction sites and construction methods, improving the efficiency of its supply has become an increasingly important issue in recent years. Concrete pumps are generally used to supply fresh concrete, but these concrete pumps have become larger year by year, and devices with a supply capacity of 100 m or more per hour are now available.

However, such large concrete pumps are expensive, and because of their large size, they are difficult to move due to their weight, shape, etc., and may not be suitable for some construction sites. Moreover, in general, the amount of fresh concrete required at one time in civil engineering work and construction work is 20 to 50 m in most cases, so this capacity is often not required. Therefore, small-sized concrete pumps that are highly mobile, can be adapted to any site, and are inexpensive are being reconsidered, and it is hoped that an efficient device will be provided.

On the other hand, concrete pumps can be roughly divided into squeeze type and piston type, and each type is used to take advantage of its characteristics. The above squeeze method is suitable for construction work where the aggregate in fresh concrete is 25 mm or less, but it cannot be used for civil engineering work where the aggregate is large, approximately 40 mm, and has a low slump.

Therefore, in order to use it for a variety of purposes including civil engineering work, the piston method must be used.

3. Since the piston system continuously pumps fresh concrete by having a cylinder device consisting of a concrete cylinder and a hydraulic cylinder perform suction and discharge operations of the fresh concrete alternately, the switching section between suction and discharge is The problem is the structure of the cylinder, and various types have been provided.First, the entire cylinder device is slid in the horizontal direction, and the concrete cylinder of the cylinder device is alternately communicated with the suction port and the discharge port. It is also provided (Special Publication No. 51-35243).

Furthermore, the most efficient fresh concrete/pressure pump does not slide the entire cylinder device, but instead installs a three-way on-off valve at the bottom of the hopper, and uses the opening/closing operation of the three-way on-off valve, that is, the three-way opening/closing. When the valve is opened, the hopper and the concrete cylinder communicate with each other to suck in fresh concrete (at this time, the concrete cylinder and discharge port are shielded by a three-way on-off valve), and when the suction is finished, the three-way on-off valve is closed and the concrete cylinder and discharge are discharged. Discharge is carried out by communicating the pipes (at this time, the concrete cylinder and hopper are shielded by three-way closing valves). but,
Conventionally, the above-mentioned system in which a three-way on-off valve is installed at the bottom of the hopper is mechanically simple and superior; There was a problem in that the three-way opening/closing valve would get caught in aggregate, making it impossible to open/close the valve completely.

In view of the above, the present inventor has previously applied for patent application No. 61-13787.
No. 4 proposed the structure of the hopper portion of the fresh concrete 1 pressure pump shown in FIG. This pump for pumping fresh concrete has a configuration in which a pair of concrete cylinders are arranged in parallel and operated alternately, but the illustrated example shows only the structure related to one side of the concrete cylinder. That is, a valve box 2a is placed below the bottom outlet 1a of the hopper 1 into which fresh concrete is charged.
A support shaft 3a rotatably supported by the valve box 2a is arranged near the bottom outlet 1a of the hopper 1.
A three-way on-off valve 4a is provided protruding from this support shaft 3a. A valve cylinder (not shown) is installed on the side of the valve box 2a, and based on the action of this valve cylinder, the support shaft 3a rotates to open and close the three-way valve 4a. . The valve box 2a is provided with a fresh concrete discharge port 15a, and this discharge port 15a is connected to a fresh concrete supply pipe (not shown).

The three-way opening/closing fp4a is formed to gradually become thinner toward the tip 4c, and curved portions 4d and 4e are formed on both the front and back surfaces of this thin-walled portion. Furthermore, the inner wall surface (bottom) of the valve box 2a with which the tip end 4c comes into pressure contact during the opening operation of the three-way on-off valve 4a in which the curved portions 4d and 4e are formed is provided with a curved portion having a chevron-shaped cross section and whose opposing surfaces are gentle. A valve seat 2C having convex portions formed at 2e and 2f is attached. Further, another valve seat 17 is installed near the bottom outlet 1a of the hopper 1. The tip of this valve seat 17 $17a
is formed into a sharp point, and is set so that the tip portion 17a comes into pressure contact with the curved portion 4d at a constant angle when the three-way on-off valve 4a is closed.

8 is a concrete cylinder and 14a is a piston.

13a is a piston rod, and 20 is a piston packing.

According to such a configuration, in the illustrated state, that is, when the three-way on-off valve 4a closes the bottom outlet 1a of the hopper 1, the hopper 1 and the valve box 2a are shielded by the three-way on-off valve 4a, and the outlet 15a is closed. The concrete cylinder 8 is in communication with the concrete cylinder 8, and in this state, the piston rod 13a extends to the left to discharge fresh concrete in the direction of arrow C, that is, in the direction of the discharge port 15a.

On the other hand, when the three-way on-off valve 4a is rotated in the direction of arrow E about the support shaft 3a to open the bottom outlet 1a of the hopper 1 and the hopper 1 and the concrete cylinder 8 are in communication, the outlet 15a is opened. and the concrete cylinder 8 are shielded by a three-way on-off valve 4a, and in this state, as the piston rod 13a contracts to the right, the ready-mixed concrete in the hopper 1 moves from the direction of arrow B to the direction of arrow B, that is, =7- It is sucked into the concrete cylinder 8.

During the above operation, the tip 4C of the three-way on-off valve 4a
is formed into a thin wall having curved portions 4d and 4e, and therefore these thin walled tip portions 4c, curved portions 4d and 4e, curved portions 2e and 2f of the valve seat 2c, and the sharp tip portion 17a of the valve seat 17. Due to the action of the aggregate in the fresh concrete, the three-way on-off valve 4a, the valve seat 1-2c,
17 is prevented from being caught between the two. That is, even if the aggregate is likely to be caught during the opening operation of the three-way on-off valve 4a, the tip portion 4C of the three-way on-off valve 4a is thin and the curved portions 2e and 2f of the valve seat 2c are connected. Curved portion 2 near the point or on the concrete cylinder 8 side
Since it is pressed against f at a certain angle, the thin-walled portion blows away the aggregate, promotes its smooth flow, and prevents the aggregate from being jammed. Furthermore, during the closing operation of the three-way on-off valve 4a, the curved portion 4d comes into pressure contact with the sharp tip 17a of the valve seat 17 at a certain angle, so the aggregate is blown away by the sharp tip 17a and the curved portion 4d. This allows the concrete to flow smoothly, eliminating the phenomenon of fresh concrete clogging inside the concrete cylinder.

However, the configuration of such a conventional pump for pumping fresh concrete, in particular, a normal three-way on-off valve is installed at the bottom of the hopper, and the intake and discharge of ready-mixed concrete is carried out by the opening and closing operation of the three-way on-off valve. This method has the advantage of being mechanically simple and superior, but as mentioned above, when the three-way on-off valve is opened and closed to switch between suction and discharge of fresh concrete, the aggregate contained in the fresh concrete is transferred from all three directions. The on-off valve became jammed and the opening/closing operation could not be performed completely.
As a result, the pumping is not carried out smoothly, and only the paste in the fresh concrete leaks out through the gaps between the aggregates, causing the fresh concrete inside the concrete cylinder to become dehydrated and become clogged inside the concrete cylinder. However, there was a problem in that the phenomenon that

On the other hand, according to the configuration described in Japanese Patent Application No. 61-137874, when the three-way on-off valve 4a is opened and closed in conjunction with switching between suction and discharge of fresh concrete, the aggregate contained in the fresh concrete is It does not get caught in the opening/closing valve 4a, the opening/closing operation is carried out perfectly, and the desired performance is achieved in that the ready-mixed concrete is pumped smoothly. Since the valve 4a was in surface contact with the ready-mixed concrete, the resistance during rotation became slightly large, and the volume change inside the valve box 2a became large as the three-way valve 4a opened and closed, for example. When the three-way on-off valve 4a is closed to the hopper 1 side in order to switch from discharge to intake of fresh concrete, the volume of fresh concrete may be blown up into the hopper 1, or due to a gap created in the valve box 2a. There was a problem in that fresh concrete on the discharge pipe side could flow back into the valve box.

Furthermore, in order to prevent aggregates from getting caught in the three-way on-off valve 4a, the tip of the three-way on-off valve 4a must be formed with a sharp point, and valve seats 2c and 17 must also be provided on the valve box 2a side. It also has the disadvantage that it becomes complicated and the manufacturing process becomes complicated.

Therefore, the present invention solves the problems that conventional fresh concrete pumps have, and even when switching between sucking and discharging fresh concrete using a three-way on-off valve installed at the bottom of the hopper, It is possible to continuously and smoothly pump fresh concrete without causing the aggregate contained in the fresh concrete to become stuck, and
The object of the present invention is to provide a pump for pumping fresh concrete that has a simplified configuration and is easy to manufacture.

In order to achieve the above object, the present invention disposes a three-way opening/closing valve at the bottom outlet of a hopper into which fresh concrete is charged.
A valve box arranged at the lower part of the hopper is communicated with the hopper, and a cylinder device for pumping fresh concrete is connected to the valve box, so that the cylinder device alternately sucks in and discharges the fresh concrete. In the pump for pumping fresh concrete, the valve body constituting the three-way on-off valve is basically configured as a rotary valve with a crescent-shaped cross section, one side of which is formed in an arc shape, and both ends formed with sharp points. At the same time,
A valve seat is formed on the inner wall surface of the bottom of the valve box that the sharp end of one side of the valve body comes into pressure contact with when the three-way on-off valve is opened, and a valve seat is formed to allow the fresh concrete 1 to flow smoothly. The pump for pumping fresh concrete has a removable metal plate fixed to the upper inner wall surface of the valve box, which is pressed against the sharp end of the other side of the valve body during the closing operation.

According to the present invention having the above configuration, the raw material put into the hopper is opened and closed by opening and closing the three-way valve installed at the bottom of the hopper in synchronization with the suction and discharge operations of the cylinder device that pumps the fresh concrete. Concrete is sucked into the cylinder device through the valve box, discharged, and continuously pumped through the discharge port of the valve box.

During the above operation, when the three-way on-off valve is opened and closed by the rotation of the valve body, the sharp points formed at both ends of the valve body penetrate into the fresh concrete at an acute angle, so that the penetration resistance against the fresh concrete is reduced. Minimum.

Furthermore, the sharpened part is formed into a thin wall shape, and the fresh concrete is smoothly flowed to form a valve seat on the bottom inner wall surface of the valve box, which is in pressure contact with the sharpened part on one side of the valve body, and an upper inner wall surface of the valve box to which the sharpened portion on the other side of the valve body comes into pressure contact;
Since a removable metal plate is fixed, these sharp points,
The action of the valve seat and metal plate prevents the aggregate in the fresh concrete from being caught between the valve body, the valve seat, and the metal plate. In other words, the object flows smoothly on the curved surface, and even if the aggregate is about to get caught, the sharp part of the valve body is thin-walled, and the area near the joint between the valve seat and the metal plate is smooth. To dispel the aggregate and promote its smooth flow13- to eliminate the occurrence of clogging of the ready-mixed concrete due to the clogging of the aggregate, and to continuously perform smooth pumping of the ready-mixed concrete. becomes possible.

Furthermore, by configuring the valve body as a rotary valve, even if the sharp edges at both ends of the valve body and the valve seat and metal plate of the valve box with which the sharp edges come into pressure contact are worn out, the rotation of the valve body can be prevented. Due to the margin of the stroke, extra rotation will be made to compensate for the wear, making it possible to make up for the wear and achieve close contact, preventing fresh concrete from leaking and allowing stable switching between suction and discharge over a long period of time. It can be carried out.

Jiran Group An embodiment of the fresh concrete pressure pump according to the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view showing an embodiment of a pump for pumping fresh concrete according to the present invention, and FIG. 2 is a plan sectional view showing a main part cut away. In the figure, 1 is a hopper into which fresh concrete is charged, and a pair of valve boxes 2a are installed below the bottom outlet 1a of this hopper 4-1.
, 2b are arranged.

Inside the valve boxes 2a and 2b, the valve bodies 21a and 21b constituting the three-way open/close valve have an arcuate surface on one side and a crescent-shaped cross-sectional shape with sharp points at both ends, and are rotatable. It is deployed. That is, the valve bodies 21a and 21b of this three-way on-off valve are integrally connected at right angles to the circumference of a disc-shaped base body 22, as shown in FIG. Therefore, for example, by partially cutting a cylindrical member, sharp parts 21C and 2 are formed on the base body 22 and both ends.
The valve body 21a, 2 has a crescent-shaped cross section and has a shape of 1d.
1b may be formed. A support shaft 22a (22b) is provided on the back side of this base body 22.
(22b), the valve body 21
a, 21b can be rotated.

Valve cylinders 5a and 5b are installed on the sides of the valve boxes 2a and 2b.
a, 5b rods 6a, 6b and the support shafts 22a, 22b
are connected using support rods 7a and 7b. Therefore, as the rods 6a and 6b of the valve cylinders 5a and 5b expand and contract, the support shafts 22a and 22b rotate, thereby opening and closing the valve bodies 21a and 21b constituting the three-way valve.

8 is a first concrete cylinder, which is communicated with the valve box 2a. Reference numeral 9 denotes a second concrete cylinder, which is communicated with the valve box 2b. The first concrete cylinder 8 and the second concrete cylinder 9 are connected by a connection box 10.

Further, a first hydraulic cylinder 11 and a second hydraulic cylinder 12 are attached to the coupling box 10, and piston rods 13a, 13 protrude and retract from the respective hydraulic cylinders 11.12.
Pistons 14a and 14b each having a piston seal 20 attached thereto are attached to the tip of the piston b.

Therefore, the first hydraulic cylinder 11 and the second hydraulic cylinder 1
2, the piston rods 13a, 13b and pistons 14a, 14b are set to alternately expand and contract inside the first concrete cylinder 8 and the second concrete cylinder 9. The pair of valve boxes 2a, 2b have fresh concrete discharge ports 15a, 1.
5b, and the opening edge 16a of the Y-shaped pipe 16 attached to the discharge ports 15a, 15b is connected to a fresh concrete supply pipe (not shown).

FIG. 4 is an enlarged cross-sectional view showing the structure of the valve box 2a, in which a valve body 21a having a crescent-shaped cross section is rotatably disposed, and the valve body 21a is rotatably arranged in the valve box 2a and the bottom of the hopper. Outlet 1a and discharge port 15
A can be communicated with and shielded from each other. Valve box 2a
The upper inner wall surface on the side of the concrete cylinder 8 is provided with a discharge port 15 that shields the bottom outlet 1a of the hopper during the closing operation.
A metal plate 23a, which serves as a valve seat, is removably fixed to which the other sharp portion 21c of the valve body 21a comes into pressure contact when communicating the valve box 2a with the valve box 2a.

In addition, on the inner wall surface of the bottom of the valve box 2a, there is a wall on one side of the valve body 21a, which is used during the opening operation, that is, when the discharge port 15a is blocked and when the bottom outlet 1a of the hopper and the valve box 2a are communicated with each other. A valve seat 25, to which the pointed portion 21d of the valve seat 25 is pressed, is removably fixed. Further, the valve seat 25 is formed with a pressure contact surface 25a that is pressed against the sharpened portion 21d on one side during the opening operation of the valve body 21a. It is appropriate to make the pressure contact surface 25a a gently curved surface because it allows the aggregate to flow more smoothly.

Furthermore, a metal plate 23b and a cross-sectional presser plate 24 are fixed to the upper inner wall surface of the valve box 2a on the discharge port 15a side, in close contact with one arcuate surface of the valve body 21a and in sliding contact with each other during rotation. ing. Built into this holding plate 24 are a seal member 26 that comes into close contact with one arcuate surface of the valve body 21a, a washer 27 that supports the seal member 26, and a bolt 28 for adjusting the seal position.

Therefore, the sharpened portions 21 c and 21 d formed at both ends of the valve body 21 a are attached to the metal plate 23 a during the closing operation, and the sharpened portion 21 d is in pressure contact with the valve seat 25 during the opening operation.

The enlarged sectional view in FIG. 4 shows the valve boxes 2a and 2.
Although only the structure of the valve box 2a in FIG. Furthermore, hopper 1
It is integrated with the valve boxes 2a and 2b,
It is rotatable in the direction of arrow A in FIG. 1, and the tip of the concrete cylinder 8.9 can be opened.

The operation of the pump for pumping fresh concrete according to the present invention having such a configuration will be described below.

First, fresh concrete mixed with aggregate having a predetermined particle size is charged into the hopper 1, and then the valve cylinders 5a and 5b are activated. Rod 6a of this valve cylinder 5a, 5b
, 6b are preset to be performed in the opposite direction, so that the operations of the valve cylinders 5a, 5b are performed as shown in FIGS. 5(A), (B), and (C). Then, the hopper 1 and the first concrete cylinder 8 are "closed" by the valve body 21a, and the hopper 1 and the second concrete cylinder 9 are "closed" by the valve body 21b.
"Open". That is, if one side is "open", the other side is "closed", and if one side is "closed", the other side is "open".

Cylinder device 11 of one option 1 and second cylinder device 12
The protruding and retracting operations of the piston rods 13a and 13b are performed in synchronization with the opening and closing operations of the valve bodies 21a and 21b. Therefore, as shown in FIG. 5(B), the valve body 21a
When the bottom outlet 1a of the hopper 1 is closed, the discharge port 15a and the first concrete cylinder 8 are in communication, and in this state, the fresh concrete is moved in the direction of the arrow C based on the operation of the screw I-rod 13a. direction, that is, the discharge port 15a
Discharge in the direction of. On the other hand, as shown in Figure 5(C),
When the valve body 21b opens the bottom outlet 1a of the hopper 1 and the hopper 1 and the second concrete cylinder 9 are in communication, the discharge outlet 15b and the second concrete cylinder 9 are shielded by the valve body 21b. In this state, the piston rod 13b contracts to the left and the hopper 1
The fresh concrete inside is sucked into the second concrete cylinder 9 in the direction of the arrow.

The above operation is performed by the piston 14a sliding inside the first concrete cylinder 8 and the second concrete cylinder 9.
, 14b, the fresh concrete in the hopper 1 is alternately and continuously discharged via the discharge ports 15a and 15b.

When the above operation is completed, the valve body 21a opens the hopper 1 and the first
The concrete cylinder 8 is "open" and the hopper 1 and the second concrete cylinder 9 are "closed" by the valve body 21b, and the fresh concrete continues to the Y-shaped pipe 16 side based on the operation opposite to the above. is discharged.

During the above operation, when opening and closing the valve body 21a, as shown in an enlarged view in FIG.
Since the sharpened portions 21c and 21d formed at both ends of the groove penetrate into the fresh concrete at an acute angle, the penetration resistance against the fresh concrete reaches the maximum limit of 21-. Then, when the valve body 2a closes, that is,
When shielding the bottom outlet 1a of the hopper and communicating the outlet 15a and the valve box 2a, the valve body 21
The sharpened portion 21c on the other side of the valve body 21c presses against the metal plate 23a at a predetermined angle, and when the valve body 2a is opened, that is,
When shielding the discharge port 15a and communicating the bottom outlet 1a of the hopper with the valve box 2a, the valve body 21
Since the sharpened portion 21d on one side of a is in pressure contact with the valve seat 25 at a predetermined angle, these sharpened portions 21c, 21
d, the metal plate 23a, and the valve seat 25, the valve body 21a can be opened and closed without getting caught in the aggregate in the fresh concrete.

In other words, objects flow smoothly on the curved surface, and even if aggregate is about to get caught, the sharp points 21c and 21d of the valve bodies 21a and 21b are thin-walled, and the valve seat 25 and metal plate 23a are smooth. By blowing away the aggregate near the joints and promoting its smooth flow, the jamming phenomenon is prevented. In addition, if the pressing surface 25a with which the sharp point 21d of the valve seat 25 presses is made into a gently curved surface, the aggregate can flow more smoothly.

Further, the pointed portions 21c of the valve bodies 21a and 21b.

21d, the metal plate 23a, and the valve seat 25 are worn out with use, and if a gap is formed due to the wear, it becomes impossible to shield the fresh concrete, but according to the present invention, the valve bodies 21a, 21b By configuring the valve as a rotary valve, even if the press-contact parts are worn out, the valve bodies 21a, 21b can be replaced by the amount of wear due to the margin of stroke of the valve cylinders 5a, 5b that rotate the valve bodies 21a, 21b. can be rotated extra, making up for the wear and making pressure contact, preventing fresh concrete from leaking, and allowing stable switching between suction and discharge over a long period of time.

Furthermore, by sequentially tightening the bolts 28,
The sealing member 26 is connected to the valve body 21a by the washer 27,
Since it is pressed against one arcuate surface of the valve body 21b, it is possible to maintain high sealing performance between the valve bodies 21a, 21b and the valve boxes 2a, 2b.

In this embodiment, two cylinder devices and the valve bodies 21a and 21b constituting a three-way opening/closing valve are configured to alternately and simultaneously suck and discharge fresh concrete, but one cylinder device It may be configured with a three-way on-off valve, or it may be configured with three or more valves.

According to the pump for pumping fresh concrete according to the present invention, which has been explained in detail above, the following effects are brought about.

That is, the suction of the cylinder device that pumps fresh concrete;
By opening and closing the three-way on-off valve installed at the bottom of the hopper in synchronization with the discharge operation, the fresh concrete I put into the hopper is sucked into the cylinder device via the valve box, and then discharged. It is continuously pumped out from the outlet of the valve box.

During the above operation, when the three-way on-off valve is opened and closed by the rotation of the valve body, the sharp points formed at both ends of the valve body penetrate into the fresh concrete at an acute angle, so that the penetration resistance against the fresh concrete is reduced. Minimum.

Furthermore, a valve seat is formed by flowing fresh concrete 1 smoothly onto the inner wall surface of the bottom of the valve box, in which the sharpened part is formed into a thin wall shape and the sharpened part on one side of the valve body comes into pressure contact. In addition, a removable metal plate is fixed to the upper inner wall surface of the valve box, which is in pressure contact with the pointed part on the other side of the valve body. The aggregate is prevented from being caught between the valve body, the valve seat, and the metal plate. (i.e. on a curved surface)
Not only does the object flow smoothly, but even if the aggregate is about to get caught, the thin-walled pointed part of the valve body prevents the aggregate from being caught near the joint between the valve seat and the metal plate. By promoting the splashing and smooth flow of fresh concrete5, clogging of fresh concrete due to aggregate encroachment will no longer occur, and smooth continuous pumping of fresh concrete will be possible. .

Furthermore, by configuring the valve body as a rotary valve, even if the sharp edges at both ends of the valve body and the valve seat and metal plate of the valve box with which the sharp edges come into pressure contact are worn out, the rotation of the valve body can be prevented. Due to the margin of the stroke, extra rotation will be made to compensate for the wear, making it possible to make up for the wear and achieve close contact, preventing fresh concrete from leaking and allowing stable switching between suction and discharge over a long period of time. It can be carried out.

Furthermore, since the volume change inside the valve box due to the opening/closing operation of the three-way on-off valve is minimized, there is no risk of fresh concrete being blown into the hopper when the three-way on-off valve rotates, or due to voids created in the valve box. There is no phenomenon in which fresh concrete from the discharge pipe side flows back into the valve box.

In addition, the same effects can be obtained even if the shapes of the pump itself and the valve box itself are made smaller, so there is no need to increase the size of the device, and a pump for pumping ready-mixed concrete that is small but has sufficiently high performance can be obtained. With,
It has the advantage of having a simplified configuration and easy manufacture, and reducing the cost required for manufacturing the device, so it is particularly applicable to pumps for pumping fresh concrete containing aggregate. It is valid.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing an embodiment of the pump for pumping fresh concrete according to the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is the valve body adopted in the present invention. FIG. 4 is a cross-sectional view showing an enlarged operating state of the main parts of the present invention, FIGS. 5(A), (B), and (C), and FIGS. (C) is a schematic diagram showing the operating state of the present invention,
FIG. 7 is a sectional view of a main part showing an example of a conventional structure. 1... Hopper 2a, 2b... Valve box 2C... Valve seat 7-5a, 5b... Valve cylinder 8... First concrete cylinder 9... Second concrete cylinder 10... - Connection box 11...First hydraulic cylinder 12...Second hydraulic cylinder 13a, 13b...Piston ronds 14a, 14b...Piston 15a, 15b-...Discharge port 16...7 Tube 20... Piston packing 21a, 21b... Valve body 21c, 21d = - Sharp portion 22... Base body 22a, 22b... Support shaft 23a, 23b - Metal plate 24... Holding plate 25 ...Valve seat 2
5a... Pressure contact surface 26... Seal member 27.
・・Washer

Claims (3)

[Claims] (1) A three-way opening/closing valve is provided at the bottom outlet of the hopper into which fresh concrete is charged, and the valve box placed at the lower part of the hopper communicates with the hopper, while a cylinder device for pumping the fresh concrete is connected to the hopper. suction of fresh concrete by the cylinder device connected to the valve box;
In a pump for pumping fresh concrete that performs discharge operations alternately, the valve body constituting the three-way opening/closing valve is a rotary valve having a crescent-shaped cross section with one side formed in an arc shape and a pointed portion formed at both ends. A pump for pressurizing fresh concrete, characterized in that it is configured as follows. (2) A valve seat that allows ready-mixed concrete to flow smoothly is formed on the bottom inner wall surface of the valve box, which is pressed against the sharp end on one side of the valve body during the opening operation of the three-way on-off valve. 1. The fresh concrete pressure pump described in 1. (3) A removable metal plate is fixed to the upper inner wall surface of the valve box, which is pressed against the sharp end of the other side of the valve body during the closing operation of the three-way opening/closing valve. Concrete pressure pump.