UA5214U - Low-pulse mortar pump - Google Patents

Abstract

A low-pulse mortar pump has a suction and pump-in working chambers, two valves and branch pipes for supply and discharge of the medium being pumped, the working cylinder, piston, rod, piston drive, appliance for decreasing the feeding pulsation as a cylindrical chamber, cylinders with pistons of small diameter, springs, pipe diaphragm made of elastic material.

Description

The useful model refers to pump construction and can be used in construction and building materials industry.

A known single-piston single-acting solution pump (1), which has a device for reducing supply pulsation, consisting of a cylindrical chamber, inside which a tubular diaphragm of elastic material is hermetically fixed. Several small compensating cylinders with pistons pressed through springs by pressure screws are installed on the cylindrical chamber. The cavity between the cylindrical chamber and the tubular diaphragm is filled with an intermediate fluid (for example, mineral oil).

The pumping part of this mortar pump is simple in design, but the fact that it works on the principle of single action, in order to reduce the pulsation of the supply to the level at which high-quality mechanized application of construction mortars can be carried out on the treated surfaces of buildings, it is necessary to install a large number of compensating cylinders on the cylindrical chamber, which complicates the design of the slurry pump.

Also known is the differential solution pump |2), in which the suction and discharge working chambers are made in the form of metal cylinders, in the middle of which tubular diaphragms of elastic material are hermetically fixed. The cavities between the metal cylinders and tubular diaphragms are filled with an intermediate liquid and are hydraulically connected to the piston (suction) and rod (discharge) cavities of the working cylinder.

The advantages of this solution pump are the absence of contact between the friction parts of the piston group and the pumped solution, the supply of solution in both half-cycles of the solution pump. But there are also significant drawbacks that prevent the introduction of this solution pump in construction production. The specified disadvantages include the increased complexity of the design of the working chambers, the low suction capacity due to the large volume of the suction working chamber, the insufficient reliability of the tubular diaphragms, and most importantly, the accepted ratio of the piston and rod areas of 2:11 does not ensure the supply of the solution in equal portions during the suction strokes and injection, as it does not take into account the effect of volumetric efficiency.

The main task of the useful model is to create a low-pulse solution pump of a simplified design, which really works according to the principle of double action.

The task is solved by the fact that the single-piston solution pump is equipped with an effective device for reducing supply pulsation, which is located at the beginning of the discharge nozzle and consists of a cylindrical chamber, inside which a tubular diaphragm of elastic material is hermetically fixed. Several small compensating cylinders with pistons pressed through springs by pressure screws are installed on the cylindrical chamber. The cavity between the cylindrical chamber and the tubular diaphragm is filled with an intermediate liquid (for example, water with the addition of soap) and is hydraulically connected to the rod cavity of the working cylinder, in which the following ratio of the diameters of the rod and the piston is carried out bsht - (ap pov), 2 where ysht and di - respectively, the diameters of the rod and piston; pcob - volumetric efficiency of a low-pulse solution pump, expressed in fractions of a unit.

The need for this ratio of rod and piston diameters is explained as follows. It is usually considered that differential solution pumps with one or two working bodies work according to the principle of double action (that is, the solution is supplied to the discharge pipeline in equal portions during both strokes - suction and discharge), if the ratio of the areas of the piston and rod (or the main and compensating pistons) is maintained. 2:1. But this does not take into account the influence of the volume efficiency of the solution pumps on the amount of solution portions fed into the injection pipeline in both half-cycles of the solution pump.

A feature of slurry pumps is that they have a very low volume efficiency, which is usually within 0.5...0.8. This is due to the fact that construction mortars contain a significant amount of bubble air and therefore have clearly defined elastic properties. Thanks to this, during the operation of the solution pump, there are such losses of the pumped solution and incomplete filling of the suction chamber during the suction stroke due to the expansion of the solution, incomplete pumping of the absorbed solution due to its compression, backflows of the solution through the valves during their closing operation.

Therefore, a portion of the solution enters the injection chamber

M-Mr.p.ob.,

Mr. - dol de 4 - theoretical working volume of the piston; n - stroke of the piston; poie - volumetric efficiency of the solution pump.

In order for the solution to enter the injection pipeline in equal portions in both half-cycles, it is necessary to divide the value of Mrlp.plob into two equal parts. But this will happen only when the working volume of the rod cavity is 1 x

Mrat - thanks "Plov.

On the other hand, the working volume of the rod cavity can be calculated by the formula k

Mr. - In oh) p.

Equating the given expressions, we get shetobopetov- КВ об) п 2 4 4 or гахт- 2аге- dtg-поб,

- (pe - pov) dt- nin. FACTORS from where 2

Let's see how the volume efficiency level affects the distribution of solution portions over half cycles, if the ratio of piston and rod areas is 2:1. Let Chtsob-0.5. Then, during the injection stroke, a portion of the solution equal to half of the theoretical working volume of the piston will be fed into the injection working chamber. When the piston and rod area ratio is 2:1, the entire injection stroke solution will be spent on filling the rod cavity, that is, the solution pump will work according to the true principle of single action. At tsob-0.75 and the ratio of piston and rod areas 2:1, the distribution of portions in the injection and suction strokes will be 0.25 and 0.50 of the theoretical volume of the piston, respectively, that is, the first portion will be half the size of the second. It is clear that there will be no real double action here either.

In Fig. a longitudinal section of a low-pulse solution pump is shown.

The low-pulse solution pump contains suction 1 and discharge 2 working chambers with valves C and 4 and nozzles for supply 5 and outlet b of the pumped solution. A horizontally located working cylinder 7 with a piston 8 and a rod 9 is attached to the suction working chamber. The piston 8 and the rod are driven by the drive 10. A device for reducing the supply pulsation 11 is attached to the injection nozzle b, which consists of a cylindrical chamber 12, inside which a tubular diaphragm 13 made of elastic material. The cavity 14 between the cylindrical chamber and the tubular diaphragm is filled with an intermediate liquid (for example, water with the addition of soap) and is hydraulically connected to the rod cavity 16 of the working cylinder by means of a nozzle 15. In order to prevent the possibility of closing the hole that provides the entrance to the nozzle 15 from the side of the cylindrical chamber, a limiting plate 17 is welded in the latter above the specified hole. To further reduce the pulsation of the supply, several small cylinders 18 with pistons 19, pressed through springs 20 by screws, are installed on the cylindrical chamber 21. To change the intermediate liquid, openings 22 and 23 with closing devices are provided.

The low-pulse slurry pump works as follows. When the piston 8 moves to the right, the solution is sucked into the working chamber 1 through the nozzle 5 and valve C. At the same time, the intermediate squeezed out of the rod cavity 16 compresses the tubular diaphragm 13 and injects the solution into the pipeline. During the movement of the piston 8 to the left, the solution from the working chamber 1 through the valve 4 is squeezed into the working chamber 2, from which it enters the nozzle 6 and the tubular diaphragm 13. At the same time, one part of this solution is pumped into the pipeline, and the second fills the expanding tubular diaphragm due to the flow of the intermediate liquid into the rod cavity. Since the working volume of the rod cavity is half of the volume of the solution supplied to the tubular diaphragm in the injection stroke, the portion of the solution that is injected into the pipeline is equal to the portion of the solution that fills the tubular diaphragm and will be fed into the pipeline in the next stroke. Thus, a single-piston solution pump with this device for reducing supply pulsation works on the principle of double action, that is, it supplies the solution to the pipeline in equal portions in both half-cycles. Additional smoothing of supply pulsation is ensured by the presence of several compensating cylinders 18.

On the basis of the proposed design, a project was developed and a research and industrial sample of a low-pulse slurry pump with the following parameters was developed: piston diameter, mm 100, volume efficiency 0.72, rod diameter, mm 80, piston stroke, mm 80, frequency of piston strokes, 1/min. 140 diameter of compensating cylinders, mm 20 number of compensating cylinders 4 supply pressure, MPa 2.5 supply, m/h. 3.8 drive power, kW 4.0 overall dimensions, mm 650x880x640 weight, kg 220

This low-pulse slurry pump has a simple design of both the pumping part and the supply compensation device. The absence of a diaphragm in the suction working chamber makes it possible to reduce the so-called "harmful volume" of this chamber and, because of this, to improve the suction capacity of the solution pump and reduce its efficiency.

Filling the rod cavity of the working cylinder with an intermediate liquid - water with the addition of soap - improves the working conditions of the friction parts of the piston group and increases their service life. The presence of several compensating cylinders makes it possible to further reduce the pulsation of the solution supply, if the piston of the working cylinder is driven by the crank mechanism. If this piston is driven by cam or hydraulic drives, then the need for compensating cylinders disappears, since the supply of the solution will be uniform due to the double action of the solution pump.

Sources of information that were used in the description of the invention: 1. Declaratory Patent of Ukraine Me38156А IPC RO489/02. Low-pulse pump / Vasiliev A.V., Matvienko

A.M. Application 02.06.2000; Publ. 15.05.2001, Bull. Me4. 2. Pat. Czechoslovakia Me97399, class 59a, 3, 59a, Differential solution pump, 15.11.60.

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Claims (1)

A low-pulse solution pump, which contains a suction and discharge working chamber with two valves and nozzles for the supply and discharge of the pumped medium, a horizontally located working cylinder with a piston and a rod, a piston drive, a device for reducing supply pulsation in the form of a cylindrical chamber, on the outer surface of which several cylinders with small-diameter pistons pressed by springs, and in the middle - a tubular diaphragm of elastic material is hermetically fixed with the formation between the cylindrical chamber and the tubular diaphragm of a cavity filled with an intermediate liquid and hydraulically connected to the rod cavity of the working cylinder, which differs in that between with the diameters of the cylinder, the following ratio of sth 2 with de ysht and dp is performed - respectively, the diameters of the rod and piston; Poeb - volumetric efficiency of the low-pulse solution pump, expressed in fractions of units.