JPS6047885A - Operation control device for piston pump for pumping fluidic body - Google Patents

Abstract

PURPOSE:To prevent generation of pulsation as well as vibration by a method wherein a pair of driving cylinders are provided with operation detectors to begin the advancing motion and pressurize the fluidic body in one pump cylinder when the delivery motion of the other cylinder is almost finished while the continuous delivery of the fluidic body is effected in accordance with the switching motion of delivery ports. CONSTITUTION:When first driving piston 8a is converted from the retreating motion into the advancing motion thereof and the conversion is detected by a conversion detector 48a, the detecting signal is inputted into a control circuit 51, the solenoid 44a of a solenoid switching valve 42a for first delivery valve is excited to open the first delivery valve 31a and the flow body, such as concrete for example, in the first pump cylinder 2a is discharged through a delivery pipe 30. In this case, the advancing motion detector 47b of the second driving hydraulic cylinder 3b detects the advancing motion of the second driving piston 8b, second servomotor 50b is driven, operating oil is supplied to the fore chamber 6b of the second driving cylinder 3b, second piston rod 5b is retreated and the concrete is induced into the second pump cylinder 2b. According to this method, generations of pulsation, vibration and noise may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operation control device for a piston pump for pumping a fluid, and in particular, to a device for controlling the operation of a piston pump for pumping a fluid. A piston rod is housed in each cylinder by penetrating the partition wall between the two cylinders in an oil-tight manner and freely displaceable. ] The front chambers O, 1, and +JAl- are each partitioned into the rear chamber on the opposite side, each of which has a driving piston fixed thereon, and each piston rod as well as M1! The present invention relates to an operation control device for a piston pump for pumping fluid, which is provided with fixed pump cylinders (a suction I and a discharge I, respectively, which are opened and closed in response to the movement of a piston rod).

Conventionally, in such a piston pump for pumping fluid, the displacement of both piston rods is temporarily stopped upon detecting that one of the driving pistons has reached -☆11]1 of its hydraulic cylinder, and during this period, the displacement of both piston rods is temporarily stopped. The opening/closing mode of the discharge port and the suction port provided in the piston cylinder is switched so that a fluid such as concrete 1 is alternately discharged from both piston cylinders. However, in this kind of control, the following (
Problems a) and (b) arise.

(a) Fluid such as concrete 1, which has already been pressure-fed into the transfer pipe, temporarily stops during the flow, and then the flow 1-2 is repeated again, so the fluid The flow reverses to pulse 11iIJL, which causes the transfer tube to vibrate. Therefore, piston bongs for pumping concrete may disturb the reinforcement installed on the floor. Furthermore, when the fluid starts flowing again after a temporary stop, there is a problem in that a large surge pressure is generated, which induces noise.

(b) When the fluid is something like concrete with poor fluidity, the pump piston retreats) I4y +
The suction volume in the C pump cylinder] 00% i
It is impossible for the concrete to be suctioned, and air is often sucked in at the same time.Therefore, in order to pump the suctioned concrete, it is impossible to suction the concrete.
When the pump cylinder is brought into communication with the discharge pipe, the air inside the pump cylinder is reduced to 1.5 cm by the concrete pressure already pumped into the discharge pipe. h$(9j l～
As a result, the concrete in the 1st ejection '1'□'1 flows back into the pump cylinder, degrading the transport efficiency. Moreover, since the backflowing concrete must be pumped by the pump piston, serve pressure is very likely to occur.The present invention eliminates these conventional drawbacks.
This is an excellent design for fluid pumping that prevents the generation of surge pressure in the discharge pipe, prevents vibration of the discharge pipe, suppresses noise generation, and further improves pumping efficiency. The purpose is to provide an operation control device for piston pumps.

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
First, in FIG. 1, a piston pump 1 for pumping a fluid, such as concrete, has a pair of first and second pump cylinders 2a and 'lb, and a pair of first and second driving hydraulic cylinders. 3a, 3b are arranged concentrically, and both cylinders 2a, 3a: penetrate partition walls 4a, 4h between 2h, 3b in an oil-tight and freely displaceable manner.

3a; 2b, a first and second piston 5a in 3b;
5b are respectively accommodated, and each piston rod 5α.

5b has a first and a second . Drive hydraulic pressure 7 cylinders 3
a, 3b inside the first and second pump cylinders'la, 2
The first and second drive pistons 8a, (3b) partitioning into the front chamber 6 (Z, 6h) on the 6 side and the rear chambers 7a, 7b on the opposite side are respectively fixed, and each piston rod 5
(Z, the other end of 5b has the first and second pump cylinders.
First and second pump pistons 9a, 9b that slide inside the pump cylinders 2a, 21r are respectively fixed, and each pump cylinder 2a, 21r has a first and second suction port ioa, 10, ! 1, and first and second discharge ports 1'1a, , 11&, respectively.

First and second bong cylinders 2a, 2b, and first and second driving hydraulic cylinders 3a.

The parts attached to the second pump cylinder 2h and 3b have the same structure, and from now on, the structure of the parts corresponding to the first pump cylinder 2a and the first driving hydraulic cylinder 3a will be explained with the subscript "a". The structure of the part corresponding to the second driving hydraulic cylinder 3z is also the same, and the same reference numerals with suffixes are shown in the drawings, and detailed explanations and explanations are omitted. Note that items without subscripts a and b are common to both.

A first hydraulic pump 128 is provided to supply hydraulic oil to the front chamber 6a and rear chamber 7a of the first driving hydraulic cylinder 3a to drive the first piston rod 5a once. This first hydraulic pump 12d is a swash plate type bidirectional variable displacement pump,
Both discharge ports are connected to the rear chamber 7α and the front chamber 6a via hydraulic oil passages 134 and 14Q, respectively. Both hydraulic oil passages 13a.

A branch oil passage 15 (Z, 15a) branched from the middle of 14a is connected to an oil passage 19a equipped with a hydraulic regulator valve 18σ via a 3-bot 3-position switching valve 17a, and this oil passage 19a is connected to an oil tank 20. connected to.

The 3-port 1-3 position switching valve 17a is of a pilot hydraulic type, and when both branch oil passages 15 ff, , 16 Q have the same working oil pressure, it maintains the neutral position shown, and one branch oil passage 15 d When the oil pressure of the other branch oil passage 16a becomes higher than that of the other branch oil passage 16a, the switching position is reached where the other branch oil passage 16a is communicated with the oil passage 19.2, and the oil pressure of the other branch oil passage 16a becomes higher than that of the one branch oil passage 15a. When the pressure becomes high, a switching position is reached in which one branch oil passage 754 is communicated with the oil passage 19.7. The hydraulic regulator valve 18α opens when the hydraulic pressure on the J switching valve 17zz side located at 3 ports in the oil passage 19α reaches a predetermined value, and then the oil pressure of either branch that communicates with the oil passage 19a opens. It functions to keep the oil pressure of the passages 15a and 16a, that is, either one of the hydraulic oil passages 13a and 1.4a, constant.

Also, in the middle of both hydraulic oil passages 13a and 14a (,1-check valve 2
1 a, 220. are connected through each
The connecting point of these check valves 21α and 22a is connected between a pair of hydraulic regulator valves 25σ and 26Q provided in the middle of a closed circuit 24a that connects the hydraulic pump 23 and the oil tank 20. Both sleeve pressure regulator valve 25a, , 2
6σ opens when the oil pressure on the upstream side reaches a certain value.

The first suction port 1oa of the first pump cylinder 2a is provided at the lower part of the hopper 27a that stores concrete.
First suction valve 28a for opening and closing this suction port 10.7
is driven to open and close by the first suction drive cylinder 29a. Further, the first discharge port 11a of the first pump cylinder 2a and the discharge port 11/I of the second pump cylinder 2h are commonly connected to the discharge pipe 3o.

A first discharge valve 31σ is provided to open and close the first discharge port 11a, and this discharge valve 31a is opened/closed and driven by a first discharge 1 drive cylinder 32ff.

The valve closing hydraulic oil passage 33a connected to the head side hydraulic chamber of the first suction drive cylinder 29a and the valve opening hydraulic oil passage 34.7 connected to the rod side hydraulic chamber are connected to the first suction valve electromagnetic switching valve. 35σ, oil tank 20 and hydraulic pump 3
It is switchably connected to an oil passage 37 connected to 6. 1st
The electromagnetic switching valve 35 for the suction valve (Z is the position where the valve-closing hydraulic oil passage 33a is communicated with the oil passage 37 and the valve-opening hydraulic oil passage 34a is communicated with the oil tank 20 when the solenoid 38a is excited) When the solenoid 39Q is energized, the position is such that the valve-closing hydraulic oil passage 33G is communicated with the oil tank 20' and the valve-opening hydraulic oil passage 34a is communicated with the oil passage 36.

A valve closing hydraulic oil passage 400 connected to the head side hydraulic chamber of the first discharge drive cylinder 32α and a valve opening hydraulic oil passage 41a connected to the rod side hydraulic chamber are connected to the first discharge valve electromagnetic switching valve 42 ( It is switchably connected to the oil tank 20 and the oil passage 37 by the oil tank 20 and the oil passage 37.

This first discharge valve electromagnetic switching valve 42Q has a solenoid 43
When a is excited, the valve closing hydraulic oil passage 40a is connected to the oil passage 37.
and the valve opening hydraulic oil passage 41σ is connected to the oil tank 20, which is +g. When the solenoid 44a is excited, the valve opening hydraulic oil passage 40α is connected to the oil tank 20.
Hydraulic oil passage for valve opening communicates with 41. , z are communicated with the oil passage 37.

The middle of the oil passage 37 is connected to the oil tank 20 via a hydraulic regulator valve 45, and the oil pressure of the oil passage 37 is kept constant by the function of the oil pressure regulator valve 45.

A backward motion detector 460 such as a limit switch is located near the end wall of the rear chamber 7a of the first driving hydraulic cylinder 3a.
is provided. This backward movement detector 46a detects the backward movement of the first driving piston 8a, that is, the first driving piston 8a.
is separated from the first pump cylinder 2a and the detector 46
．． It detects that it has reached z and outputs a detection signal.

Further, the first driving hydraulic cylinder 3a is provided with a forward motion detector 41α such as a limit switch on the front side of the backward motion detector 46a, that is, at a position closer to the first pump cylinder 2a. This forward motion detector 47a
The first. It detects that the drive piston 8a passes the forward motion detector 4ra and moves toward the first pump cylinder 2a, and outputs a detection signal.

Further, a reversal operation detector 48Q such as a pressure switch is provided on the end wall of the first driving hydraulic cylinder 3σ facing the rear chamber 7a. The reversal motion detector 48θ detects that the first drive piston 8a once stops at the limit of backward movement 1- and then moves forward, and outputs a detection signal.

The first and second piston rods 5σ, 5b and each @
A control means 49 is provided to control the operation f11 of the magnetic switching valves 35a, 35/J, 42a, and 42/I. This control means 49 controls the first and second hydraulic pumps 12α, 1
The first and second servo motors 5 drive the swash plate 215.
0a, 50h, and a control circuit 51. Control circuit 5
1 includes first and second drive hydraulic cylinders 1) cylinders 3α, 3;
Reverse motion detectors 46Q, 46b and forward motion detector 47σ provided at h.

47h and the detection signals of the reversing motion detectors 48a and 48h are respectively input, and the control circuit 51 controls each servo motor 50a based on these detection signals.

50b and each solenoid 38a, 3Bb, 39a.

39h, 43a, 43b, 44 (outputs a signal for controlling the operation of L, 44b).

That is, the control circuit 51 controls one of the backward motion detectors 46a.
The solenoid 38 (Z) closes both the first suction port 10a and the first discharge port 11a of the first pump cylinder 2a in response to the detection signal of the first pump cylinder 2a.

430, the servo motor 50d is driven to cause hydraulic oil to flow into the rear chamber 7a of the first driving hydraulic cylinder 3a, and one reversal motion detector 48σ and the other forward motion detector 47b are driven. Based on both detection signals, the servo motor 50h is driven to cause hydraulic oil to flow into the tip chamber 6b of the second drive hydraulic cylinder 3h. The control circuit 51 also controls the operation opposite to that described above.

Next, the operation of this embodiment will be explained, but in order to make the operation easier to understand, the explanation will be divided into steps 5 to 5 and each step will be explained separately.

[First stroke] In FIG. 1, first, from the first hydraulic pump 12a to the first hydraulic pump 12a.
Hydraulic oil is supplied to the front chamber 6g of the driving hydraulic cylinder 3σ, and hydraulic oil is supplied from the second hydraulic pump 12b to the rear chamber 7h of the second driving hydraulic cylinder 3/).
As a result, the first piston rod 5a moves backward, and the second piston rod 5h moves forward. At this time, the pressure receiving area of both drive pistons 8a, 8b facing the front chamber 6 (Z, 6h) of both drive hydraulic cylinders 3σ, 3b is larger than the pressure receiving area facing the rear chambers 7a, 7h, screw I/n rod 5cL, It is set smaller by 5h, and the backward movement of both piston rods 5σ and 5b is
Faster than forward movement. On the other hand, the solenoid 39a of the first suction valve and discharge valve switching valve 35a, 42a,
43σ is excited and therefore the suction port 10a in the first pump cylinder 2a is open and the discharge port 11a is open.
is closed, the suction port 1ob of the second pump cylinder 2h is closed, and the discharge port 11h is open. As a result, concrete is sucked from the hopper 27g into the first pump cylinder 2a in response to the backward movement of the first pump cylinder 9a, and concrete in the second pump cylinder 2b is discharged in response to the forward movement of the second pump piston 9a. It is discharged into tube 30.

[Second stroke] In FIG. 2, if the backward movement of the first driving piston 8 (Z) is detected by one of the backward movement detectors 46σ,
The first servo motor 50a is controlled by the control circuit 51, and the first hydraulic pump 1? Hydraulic oil is supplied to the rear chamber 7Q of the first driving hydraulic cylinder 3a through the hydraulic oil passage 13a, and the solenoid 38a of the first suction valve electromagnetic switching valve 35a is energized, and the first suction valve 28a is activated. The valve is closed. Solenoid 43 of Denken switching valve 42a for first discharge valve
a remains energized and therefore the first discharge valve 31
Since valve a remains closed, the first pump cylinder 2
The inside of a is sealed).

[Third stroke] In FIG. 3, the first driving piston 8σ reverses from the backward movement to the forward movement, the air mixed in the conc 'J-1- in the first pump cylinder 2α is compressed, and the first When the pressure in the rear chamber 1a of the eleventh drive hydraulic cylinder 3Q reaches a predetermined pressure, one of the reversal operation detectors 48tZ performs a detection operation.

When the reversal operation detector 48a and the spider detection signal are input to the control circuit 51, the control circuit 51 controls the first discharge valve solenoid switching valve 42 (1 non-noid 44 (L) corresponding to the first pump cylinder 2a). is excited to open the first discharge valve 31a.Thus, the concrete in the first pump cylinder 2a is discharged into the discharge pipe 30, but since the inside of the first pump cylinder 2a is already pressurized, Backflow of concrete from the discharge pipe 30 into the first pumping cylinder 2a does not occur.On the other hand, in the 24th minf.

In the cylinder 2h, each solenoid 39b of the electromagnetic switching valve 35/1, 42a for the second suction valve and the second discharge valve
, 43b are excited, thereby opening the second suction valve 21 and closing the second discharge valve 31. At this time, the detection signal from one of the reversal motion detectors 48a is
1+ circuit 51, the forward motion detector 47b of the second drive hydraulic cylinder 3h detects the second drive piston 8.
When the forward motion of h is detected, the second servo motor 5[1 of the second hydraulic pump 12z is driven, hydraulic oil is supplied to the tip chamber 6hK of the second driving hydraulic cylinder 3b, and the second piston rod 5b is moved backward. Accordingly, concrete is sucked into the second pump cylinder 2h.

When one of the reversing motion detectors 48a performs a detection operation, the forward motion detector 4 corresponding to the second driving hydraulic cylinder 3h
7b is the second. When the forward motion of the drive piston 8b is not detected, the first servo motor 50C of the first hydraulic bong 12a is controlled, and the first
, the supply of hydraulic oil to the rear chamber 7a of the driving hydraulic pressure/cylinder 3a is stopped, and the forward movement of the first driving piston 8a is
It stops until the other forward movement detector 47/) detects it.

Further, although the other forward motion detector 47'z detected the forward motion of the second drive piston 8b, one of the reverse motion detectors 48a detected the reverse motion of the first drive piston 8a. When not in use, the second hydraulic pump 1215
The second servo motor 50 & of the second . The amount of hydraulic oil supplied to the rear chamber 7h of the driving hydraulic cylinder 3b is reduced. As a result, the forward movement of the second driving piston 8z is decelerated.

[Fourth stroke] In FIG. 4, concrete 1 in the first pump cylinder 2a continues to be discharged, and concrete is sucked into the second pump cylinder 2h.
Also, the backward motion detector 46A is activated by the second. When the backward movement of the drive piston 8h is detected, the second servo motor 5Q&
is driven, hydraulic oil is supplied from the second hydraulic pump 12b to the rear chamber 7b of the second driving hydraulic cylinder 3z, and the solenoid 38 of the second suction valve electromagnetic switching valve 35b is driven.
b is excited, and the second suction valve 28b is closed.

At this time, the supply of hydraulic oil from the first hydraulic pump 12α to the rear chambers 7a, -\ of the first driving hydraulic cylinder 3a continues.

[Fifth stroke] In FIG. 5, when the other reversing motion detector 48b detects the reversing motion of the second drive piston 8h, the solenoid of the second discharge valve electromagnetic switching valve 42A corresponding to the second pump cylinder 2h is activated. 441) is excited (1), and the second discharge valve 31/
I is opened, and therefore the concrete in the pump cylinder 2z is discharged to Hg 30. On the other hand, each solenoid 39 (1,430°) of the first pump cylinder 2 (l or first suction valve and first discharge valve Lfl electromagnetic switching valve 35a, 42.2 is energized, and the first suction valve 28a is opened, and the first discharge valve 31/2 is closed. Also, in response to the detection of the forward movement of the first and drive piston 8α by one of the forward movement detectors 47 (!), The servo motor 50α is driven and the first
The hydraulic oil of the hydraulic pump 12α is the first. Concrete is supplied to the tip chamber 6a of the drive hydraulic cylinder 3a, and as the first piston rod 5σ retreats, concrete is sucked into the first pump cylinder 2a.

The second, driven piston 8 by the other reversing motion detector 41
h's reversal motion detection timing and one forward motion detector 47.
1st by Z. Regarding the shift in the forward motion detection timing of the drive piston 8σ, the temperature in °C is as described in the above-mentioned third stroke.
The operation of the second drive piston 8h is stopped, or the operation of the first drive piston 8h is stopped. The forward movement of the drive piston 8a is decelerated.

In this way, return to the A1 process shown in FIG.
~The fifth stroke is repeated, and concrete is discharged from the first and second pump cylinders 2a, , 'lb to the discharge pipe 30.
It is discharged alternately.

In the embodiment described above, in the third and fifth strokes, the reversing motion detectors 48a, , 4a b
When the reversal operation of the drive screws 8a and 8h was detected, the first and second discharge valves 31Q, 31A were opened, but the reversal operation detector 48a and the forward movement detector 47/ The first discharge valve 31α is opened by the detector number I, and the reverse motion detector 48b and the forward motion detector 4γa are opened.
The second discharge valve 31A may be opened by the detection signal.

FIG. 6 shows still another embodiment of the present invention,
The first suction port 10a of the first pump cylinder 2a and the first
A first on-off valve 53a that can alternately open and close the discharge port 11α is driven to open and close by a first on-off drive cylinder 54a, and a second
A second opening/closing valve 53A that can alternately open and close the second suction port 1015 and the second discharge port 11/) of the pump cylinder 2h is driven to open and close by the second opening/closing and driving cylinder 54h.

In addition, a third on-off valve 55 that can alternately open and close the two company outlets 11a and 11A is provided at the connecting portion between both pump cylinders 'l a, , 'l h and the discharge pipe 30. is driven to open and close by the third opening and closing drive cylinder 56.

According to this embodiment, there are three opening/closing, @moving cylinders 54a.
, 54b and 56 have both suction ports 10σ.

It is possible to control the opening and closing of the four cylinders 29 (L, 29'b, 32a) as in the embodiment shown in FIGS. 1 to 5.

The configuration is simplified compared to controlling with 32h.

As described above, according to the present invention, there is a backward movement detector for detecting the backward movement of the driving piston on the rear side of the driving hydraulic cylinder, and a forward movement of the driving piston on the pump cylinder side with respect to the backward movement detector. A forward motion detector that detects the movement of the drive piston, and a reversal motion detector that detects that the drive piston reverses from the backward motion and shifts to the forward motion are provided in each of the hydraulic cylinders for both parts. The detection signal causes both the suction port and the discharge port of one pump cylinder corresponding to the reversing motion detector to be closed, and hydraulic oil is caused to flow into the rear chamber of one of the hydraulic cylinders, and furthermore, one of the reversing motion detectors and the other A control means is provided which is configured to cause hydraulic fluid to flow into the tip chamber of the other hydraulic cylinder in response to both detection signals of the forward motion detector of the hydraulic cylinder.

Therefore, just as the discharge action of one piston pump is about to end, the other piston pump begins to move forward and pressurizes the inside of the other pump cylinder.
] According to the switching operation, the fluid is discharged continuously without interruption, pulsation is prevented as much as possible, vibration of the transfer pipe and generation of surge pressure are suppressed,
As a result, noise generation can also be suppressed. In addition, since the fluid after pressurization is discharged according to the opening of the discharge port, the occurrence of backflow is prevented, the pumping efficiency can be improved, and the generation of surge pressure can be prevented. .

[Brief explanation of the drawing]

1 to 5 are overall hydraulic circuit diagrams sequentially showing the operating state for each stroke of one embodiment of the present invention, and FIG. 6 is a diagram showing the configuration of essential parts of another embodiment of the present invention. 1... Piston pump, 2a, 2b... Pump cylinder, 3a, 3b... 1 (driving hydraulic cylinder, 4σ
. 4b--Bulkhead, 5a, 5h...Piston rod, 6a,
, 5 b...front chamber, 7 a+γh...rear chamber,
3a, , 8h..., drive piston, 9a, 9b
・Pump piston, 10σ. 10 b-...Suction port, 11a+11A-...Discharge port,
12a. 12h... Hydraulic pump, 46t2, 46A-°゛ Reverse movement detector 47ct, 47b... Forward movement detector,
48α.

Claims (1)

[Claims] A pair of small moving hydraulic cylinders are concentrically connected to a pair of pump cylinders, and a piston rod is accommodated in each cylinder by penetrating the partition wall between the two cylinders in an oil-tight manner and freely displaceable. , a drive piston is fixed to one end of each piston rod, which partitions the inside of the small hydraulic cylinder into a front chamber on the pop cylinder side and a rear chamber on the opposite side, and a drive piston is fixed to the other end of each piston rod, which partitions the inside of the small hydraulic cylinder into a front chamber on the pop cylinder side and a rear chamber on the opposite side. In the actuation control device for a piston bonnet for pumping fluid, in which sliding pump pistons are each fixed, and each pump cylinder is provided with a suction port and a discharge port that are opened and closed according to the movement of the piston rod, Hydraulic oil is supplied to the rear chamber and the rear chamber (a pair of hydraulic pumps are provided corresponding to the hydraulic cylinders for both drives);
a pair of backward motion detectors each provided on the rear side of the hydraulic cylinder for both drives, and detecting backward motion of the drive piston in the opposite direction from the pump cylinder; a pair of forward motion detectors provided on each of the hydraulic cylinders to detect a forward motion of the first drive piston; a pair of reverse motion detectors provided on the rear side to detect a reverse motion of the drive piston; The detection signal from the backward motion detector closes both the suction port and the discharge port of one pump cylinder corresponding to the backward motion detector, and causes hydraulic fluid to flow into the rear chamber of one hydraulic cylinder. and a control means configured to cause hydraulic oil to flow into the tip chamber of the other hydraulic cylinder in response to detection signals from both a reverse motion detector and the other forward motion detector. Pump operation control device.