JPH06159260A - Squeeze type pump - Google Patents

Abstract

PURPOSE:To Prevent occurrence of a neck-in phenomenon in a pipe line due to pressure and temperature during conveyance of ready-mixed concrete led from the suction side by a rotor having at its opposite ends rotors which can rotate and press a pump tube within a drum, from the discharge side to a predetermined position. CONSTITUTION:Recesses are formed at 6, 9 and 12 o'clock positional at which a drum 9 and a pump tubing is pressed by rollers of a rotating roller, on the drum side 9, and a temperature sensor 8 is located in each of the recesses so that a drive machine associated with the temperature sensors 8 is adjusted in order to prevent occurrence of a neck-in phenomenon in a pipe line on the discharge side.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a squeeze type pump for pumping slurry, especially fresh concrete.

[0002]

2. Description of the Related Art A squeeze pump mainly comprises a rubber-made pumping tube containing a reinforcing core, a steel or rubber roller and a rotor, and a steel drum containing the same. The pumping tube is connected to the piping on the suction side for sucking the fluid and the discharge side for discharging the fluid. The pumping tube squeezes the fluid from the suction side to the discharge side while being pressed by the rollers.At this time, a pulling force acts on the suction side and a compression force acts on the discharge side, so that it does not separate from the drum at each position. It is firmly bound. Of course, this binding force is strong enough to withstand the suction and discharge pressures.

[0003]

The physical properties of rubber and iron constituting the squeeze pump are as follows: volume expansion coefficient [l / ° C.] thermal conductivity [cal / cm, s, deg] rubber 7 × 10 ⁻⁴ 0. 6 × 10 ^-3 iron 0.33 × 10 ^-4 0.11 and the pumping tube is sandwiched between the drum and the roller in the pump case, but when pumping at low pressure, the rotation speed of the roller is also small, The heat generated by bending and sliding of the pumping tube is small, but when pumped at high pressure, it rapidly increases. Now, the drum diameter is 1000 mm (pumping tube curve outer radius R:
500 mm), the pair of rubber rollers completely presses the pumping tube.
At 80 °, the length of the pumping tube in contact with the drum is 1570 mm {1000 × (3.14 /
2)}. Here, when the slurry is pressure-fed at an internal pressure of 10 kgf / cm ^{2 The} elongation of the pumping tube due to the internal pressure ΔL ₁₀ = 1
2.5 mm (0.8% from Table 1) When pumping slurry at an internal pressure of 20 kgf / cm ² Elongation due to the internal pressure of the pumping tube ΔL ₂₀ = 1
9 mm (1.2% from Table 1), which indicates the amount of elongation from 6:00 to 12:00. Here, FIG. 1 is a diagram showing the relationship between the internal pressure and the elongation of the pumping tube. On the other hand, the pumping tube at that time generates heat by sliding and bending, so that the temperature becomes constant after a certain time. FIG. 2 shows the relationship between the internal pressure of the pumping tube and the temperature. The difference between the thermal expansion of the pumping tube and the thermal expansion of the case when the slurry is pressure-fed at an internal pressure of 10 kgf / cm ² is 1570 × {50 (heat generation) −20 (normal temperature)} × 7 × 10
^-4 -1570 x (50-20) x 0.33 x 10 ^-4 = 3
It is 1.4 mm. The amount of expansion of the drum from the amount of expansion due to heat generated by sliding and bending of the pumping tube from 6:00 to 12:00 minus the amount of expansion of the drum is the amount of expansion of the pumping tube extending to the outside of the drum. .
Since the drum is in contact with the pumping tube, it has the same temperature. Next, looking at the internal pressure of 20 kgf / cm ² , here, 1570 × (150-20) × 7 × 10 ^-4 -1570 ×
(150-20) × 0.33 × 10 ⁻⁴ = 136 mm When the elongation due to internal pressure and the elongation due to heat generation are added, when the internal pressure is 10 kgf / cm ² , 12.5 + 31.4 =
When the internal pressure is 43.9 mm and the pressure is 20 kgf / cm ² , 19 + 136 = 155
mm When the internal pressure is 10 kgf / cm ² , 43.9 mm is the extension of the pumping tube, and when the internal pressure is 20 kgf / cm ² , 155 mm is the extension of the pumping tube.
This extension will be concentrated between the metal fitting lashing points on the discharge side of the pumping tube. If the distance from the 12 o'clock position to the securing point is 600 mm, the following deformation of the pumping tube will occur during operation. 600 + 43.9 = 64 at 10 kgf / cm ²
When 3.9 mm and 20 kgf / cm ² , 600 + 155 = 755 m
m The internal pressure is not applied to the pumping tube and the heat is applied at room temperature, so when pumping the internal fluid,
The axial elongation always occurs. Since the pumping tube is fixed at the discharge tip, the pumping tube becomes constricted as shown by the chain double-dashed line in FIG. The occurrence of this constriction causes the following problems. A: The constricted portion forms a protrusion with respect to the inside of the pumping tube, and the protrusion is worn early by the slurry fluid, resulting in a shortened life of the pumping tube. B: When the roller presses the constricted portion, the driving torque increases and the rotation fluctuates, and the slurry fluid pressure feeding becomes unsteady. C: Concentrated strain and load are applied to the rubber layer and the reinforcing layer of the pumping tube in the constricted portion, which causes early deterioration.

Therefore, an object of the present invention is to provide a squeeze type pump which eliminates the discharge side constriction during operation of the pumping tube and prevents premature wear of the pumping tube to stabilize the life and stabilize the discharge capacity. Is.

[0005]

The present invention has been achieved as a result of intensive research for solving the above-mentioned problems, that is, it is sensed by a temperature sensing sensor of a drum near 12:00, which is the highest heat generating portion of a pumping tube. The temperature is electrically converted, and the signal is applied to the screw jack or hydraulic cylinder that supports the pumping tube securing portion, and the securing portion is moved in the axial direction of the pumping tube by the operation of the screw jack or hydraulic cylinder. By acting on the power mechanism that expands and contracts in parallel, the lashing position of the pumping tube is extended by extending the lashing position with a predetermined pumping tube temperature rise (drum temperature rise) with respect to the lashing position set at room temperature. Shall not occur. It is most convenient to connect the temperature sensor to the drum, and it is easy to replace the pumping tube. However, when the temperature rise of the pumping tube itself is 20 kgf / cm ² internal pressure, the temperature rises from room temperature to 150 ° C. However, since the drum is generally made of a metal having a high thermal conductivity, 20 kgf / cm ²
Even at the internal pressure, it stays around 80 ° C. For this reason, there is also a method in which the sensor attached to the drum has a periphery thereof made of a material having low heat conductivity, and only the contact surface thereof is directly contacted with the pumping tube. There is also a method of embedding the sensor itself in the constituent material of the pumping tube and taking it out from the end surface of the pumping tube, but since the temperature rise of the pumping tube and the drum temperature rise are in a proportional relationship, this relationship can be measured accurately. If so, the required pressure and the extension amount of the pumping tube can be set practically. The pumping tube is stretched with a screw jack or a hydraulic cylinder, and this attachment is usually done on the discharge side, which is the extension side, but even on the suction side, it is sufficient to set the operating amount appropriately. Can meet the demand.

[0006]

The present invention will be described with reference to the drawings. FIG. 3 is a part of a cross-sectional view for explaining the constriction 11 of the conventional pumping tube 5, showing a state when the roller 1 is pressed at 12:00. The pumping tube has a length of, for example, 600 mm, and a constriction 11 is generated above and below the center of the extended pumping tube 10 and the securing jig 7 with the drum.

FIG. 4 is a sectional view for explaining the present invention.
The pumping tube 5 is loaded in the drum 9, and the rollers 1 are rotatably and slidably attached to both ends of the rotor 2. The temperature sensing sensor 8 is pressed at the 12 o'clock portion of the drum, and the outer circumference of the pumping tube can be felt. The pumping tube fastening metal fitting 7 is fixed to the pipe 6 inserted in the discharge side end 5b of the pumping tube.
The constriction preventing jig 4 (hydraulic cylinder or screw jackie) is fixed to the other end 7b of the.

FIG. 5 illustrates the control of the constriction preventing jig 4. Reference numeral 11 is a controller, and reference numeral 12 is a code 12 for transmitting an instruction from the controller 11 to the constriction preventing jig 4. When the temperature detecting sensor 8 detects a temperature rise, the control device 11 operates the electric motor 4a of the constriction preventing jig 4 to rotate the screw 4b to move the fastening metal fitting 7 to the right side in FIG. There is. In the case of temperature drop, the opposite is true.

EXAMPLES The effects of the present invention will be described by way of examples. A pair of drum inner diameter 1000mm, pumping tube inner diameter 100mm, outer diameter 130mm (wall thickness 15mm), roller outer diameter 200mm. Volumetric expansion coefficient of steel drum 0.33 × 10 ⁻⁴ [l /
℃] Pumping tube volume expansion coefficient 7 × 10 ^-4 [l /
[° C], the pumping tube elongation at an internal pressure of 10 kgf / cm ² is 12.5 mm (due to pressure), the pumping tube elongation at an internal pressure of 20 kgf / cm ² is 19 mm (due to pressure), the pumping at an internal pressure of 20 kgf / cm ² Tube heat generation temperature 150 ° C Pumping tube heat generation temperature when the internal pressure is 10 kgf / cm ² 50 ° C The amount by which the pumping tube expands more than the drum due to the internal pressure and heat generation When the internal pressure is 10 kgf / cm ² 43.9 mm When the internal pressure is 20 kgf / cm ² 155 mm 12:00 The temperature of the drum in contact with the pumping tube at the position 35 ° C at the internal pressure of 10 kgf / cm ^{2 At} the internal pressure of 20 kgf / cm ² 80 ° C at 12 o'clock The temperature of the pumping tube and its extension can be estimated by measuring the temperature rise of the drum at the position. So
At that time, you can see the required extension amount, so the internal pressure is 10 kgf /
When cm ² 43.9mm, was set to extend 155mm when the 20kgf / cm ^2.

The effects of the present invention are shown in Table 1. The life of the pumping tube was expressed as the total volume passing through it.

[Table 1] The exothermic temperature varies greatly depending on the composition of the fluid to be pumped and the flow velocity, but in the present invention, fresh concrete (cement amount 4
00kg / m ³ , slump 12cm, maximum aggregate size 20
mm) and the flow rate was 3 m / sec.

EFFECTS OF THE INVENTION In the conventional method, local abrasion of the inner rubber occurs at a position immediately after the roller leaves the pumping tube, the pumping becomes unsteady, and finally the pumping tube is damaged and becomes unusable. In the structure of the invention, no constriction or local wear occurs, and the rubber on the inner surface is uniformly worn, so that the life of the pumping tube can be remarkably improved.

[Brief description of drawings]

FIG. 1 is a graph showing a relationship between an internal pressure of a pumping tube and a temperature.

FIG. 2 is a graph showing the relationship between internal pressure of a pumping tube and elongation.

FIG. 3 is a schematic side view for explaining a “constriction” on the fresh concrete discharge side of the pumping tube.

FIG. 4 is a schematic cross-sectional view showing a state where the rollers at both ends of the rotor in the drum of the pumping tube of the present invention are at 12:00 and 6:00.

FIG. 5 is a schematic diagram for explaining control of the neck-preventing jig of the present invention.

[Explanation of symbols]

 1 Roller 2 Rotor 3 Hopper 4 Constriction prevention device 4a Electric motor 4b Screw 5 Pumping tube 5a Hopper insertion port at the tip of the pumping tube 5b Piping insertion port at the tip of the pumping tube 6 Piping 7 Pumping tube securing metal fittings 7a Piping of metal fittings Fastening part 7b Constriction prevention device for securing metal fittings Fastening part 8 Temperature sensor 9 Drum 10 Constriction 11 Control device 12 Cord

Claims (2)

[Claims] 1. A squeeze pump in which a roller for pressing a pumping tube inscribed in a cylindrical drum is rotated by a rotor shaft to extrude a liquid sucked into the pumping tube to increase the temperature of the pumping tube. The temperature sensor to detect is attached to a part of the drum, and the temperature rise is detected by the temperature sensor.
A squeeze pump, characterized in that a motive power machine is provided for moving the pumping tube securing portion on both the discharge side and suction side of the pumping tube and in the pumping tube axial direction. 2. The pumping tube shaft moving mechanism installed at the other end of the pumping tube fastening portion fixed to the pipe inserted at the tip of the pumping tube on the discharge side is a hydraulic cylinder or a screw jack. The squeeze pump according to claim 1.