JPS624704Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a reciprocating pump that handles slurry, and in particular, to an improvement of the reciprocating pump that prevents failures caused by solid matter adhering to the seal packing of the plunger. be.

Conventionally, in reciprocating pumps that handle slurry,
When the plunger, which was in contact with the liquid handled by the pump during the forward stroke, enters the seal seal and seal presser during the backward stroke, solid matter also enters, impairing the integrity of the seal and accelerating the wear of the seal and plunger. Ta.

From this point of view, in order to overcome the problems of the reciprocating pump mentioned above, we first developed a method for the seal presser of the plunger of the reciprocating pump.
When the plunger is retracted to the maximum, a flush pipe is inserted through and opened in the cylinder part that is always located behind the retreating end of the plunger, and a packing is provided behind the opening of this pipe and forward of the opening on the side of the pump chamber. By configuring the flushing part without providing any packing at all, and flushing a predetermined amount of flushing liquid from the flushing pipe under the action of a flushing pump at a discharge pressure slightly higher than the suction pressure of the plunger, the packing and packing presser side are flushed. Developed a reciprocating pump that washes away solid matter adhering to the plunger, and received Utility Model Registration No. 1068288 (Jikkosho
49-3523) was registered as a utility model.

However, in the conventional reciprocating pump proposed earlier, the flushing liquid supply system runs from the mother liquor tank to the flushing pipe via the flushing pump, strainer, flow meter, flow rate adjustment needle valve, and check valve. However, when a centrifugal pump, for example, is used as the flushing pump, there is no reliable guarantee that the mother liquor will be flushed correctly during the suction stroke of the main pump. In other words, in the previously proposed reciprocating pump, there is no specific control means for controlling the discharge flow rate of the flushing liquid so that the slurry concentration is always constant to achieve the most efficient and economical cleaning of the plunger. was not even considered.

In addition, as a conventional automatic concrete dosing device,
In a system configured to deliver concrete using a piston pump mechanism, a technology has been proposed that cleans the inner wall of the pump chamber while supplying water when the piston retreats, in order to clean the inside of the pump chamber from the perspective of preventing concrete from adhering. (Special Publication No. 51-8205). However, this type of cleaning technology simply sets the timing of the water supply and does not provide any efficient and economical control over the supply of cleaning water and the cleaning of the piston so that the slurry concentration of the cleaning slurry is always constant. Not only is this consideration not taken into account, but rather the muddy water that washed inside the cylinder accumulates in the cylinder and has the disadvantage of biting solid matter when the piston retreats. In addition, there remained a major problem regarding wear when the piston moves forward.

Furthermore, in conventional pumps for transferring muddy water, muddy water is sucked into one side of the piston by the reciprocating movement of the piston pump, and then pumped under pressure. A structure has been proposed in which the piston outer peripheral surface allows muddy water to flow out to the side (Japanese Patent Publication No. 32-5333). However, in this type of pump technology, a fresh water pump is configured with a plunger that interlocks with the piston in the same phase as the piston pump, and this fresh water pump chamber and the other side of the piston are supplied via a supply valve and a discharge valve. It is connected by a channel and a discharge channel, and is configured so that fresh water under a specified pressure always acts on the other side of the piston, making it efficient and economical for supplying fresh water and cleaning the piston so that the concentration of muddy water is always constant. Not only is no consideration given to control means, but rather the structure of the fresh water supply system for applying fresh water at a predetermined pressure to the other side of the piston is complicated.

However, in today's coal slurry treatment processes, for example, there is a problem that the slurry concentration is unnecessarily diluted by flushing liquid, and strict concentration control has come to be required to maintain a constant slurry concentration at all times. It's on. For this reason, in conventional reciprocating pumps, in order to maintain the slurry concentration appropriately, it has sometimes been necessary to reduce or stop the supply of flushing liquid at the expense of damaging the pump due to the slurry.

In order to overcome all the problems of the conventional reciprocating pumps mentioned above, the inventor of the present invention conducted various studies and prototypes, and as a result, he decided to use a plunger type reciprocating pump similar to the main pump as a flushing pump. The electric motor, which is the drive source for the crank mechanism that drives the pump, is used as a common drive source, and each rotating shaft is coaxially connected by a coupling via the crank mechanism. The rotational phase difference is set to 180°, and a check valve is installed in the connecting pipe between the flush pipe and the reciprocating pump for flush fluid supply to prevent back flow of the flush fluid, and the flow rate of the flush fluid relative to the flow rate of the fluid handled by the main pump is adjusted. By making the ratio of mixed amounts, that is, the dilution rate, always constant regardless of the pump rotation speed, and by configuring the supply amount of the flush liquid to increase or decrease in proportion to the magnitude of the plunger retraction speed, the main pump handles the liquid. It has been found that it is possible to properly control the concentration of the liquid and to achieve efficient and economical cleaning of the plunger with the flushing liquid, thereby solving the above-mentioned problems.

Therefore, an object of the present invention is to provide a reciprocating pump configured to discharge flush liquid during the suction stroke of the main pump, which performs the pump operation by reciprocating the plunger, so that the main pump can smoothly operate on the slurry. With a simple configuration and without the need for a special control mechanism, it is possible to keep the concentration of the main pump handling liquid constant by keeping the amount of the flushing liquid mixed in with the flow rate of the main pump handling liquid constant, and to maintain the concentration of the main pump handling liquid at a constant level. An object of the present invention is to provide a reciprocating pump that can obtain the most efficient and economical cleaning effect using liquid.

In order to achieve the above purpose, in the present invention,
A flushing pipe is provided in the cylinder part that supports the plunger that performs the main pump operation, behind the maximum retracted position of the plunger where it comes into contact with the liquid handled by the pump, and a flushing area is formed on the front side of the pump chamber from this flushing pipe. The reciprocating pump is configured such that a gasket is provided on the rear drive source side, and a reciprocating pump for flushing liquid supply is connected to the flushing pipe so that the flushing liquid cleans the surface of the plunger. Rotation phase difference of reciprocating pump is 180
A check valve is installed in the connecting pipe between the flush pipe and the reciprocating pump for supplying the flush liquid to prevent backflow of the flush liquid, and the ratio of the mixed amount of the flush liquid to the flow rate of the liquid handled by the main pump ( The main pump and the flushing liquid supply reciprocating pump are commonly driven so that the dilution rate (dilution rate) is always constant regardless of the pump rotation speed, and the amount of flushing liquid supplied increases or decreases in proportion to the magnitude of the plunger retraction speed. It consists of a structure connected to a source.

The reciprocating pump according to the present invention configured as described above has a rotational phase difference of 180° between the main pump and the reciprocating pump for flushing liquid supply, thereby flushing the plunger in synchronization with the suction stroke of the main pump. can be carried out appropriately. In addition, since the ratio of the amount of flushing liquid mixed in to the flow rate of the main pump liquid is always constant regardless of the pump rotation speed, concentration control is possible so that the concentration of the main pump liquid, that is, the slurry, can always be kept constant. It can be achieved. Furthermore, by making the amount of flush fluid supplied increase or decrease in proportion to the magnitude of the plunger retraction speed, the minimum amount of flush fluid required is always flushed, allowing the flush fluid to be used economically and in the most efficient manner. Good flushing cleaning can be achieved.

Next, embodiments of the reciprocating pump according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a reciprocating pump according to the present invention, and reference numeral 10 indicates a cylinder that supports a plunger 12 that performs pumping operation of the main pump, and a part of this cylinder 10 is equipped with a flush pipe. 14 is inserted and arranged. The flash pipe 1
4 is installed at the rear of the position (indicated by the chain line) where the most extreme end 12a of the plunger 12 retreats to the maximum during the suction stroke, and from the opening of the flush pipe 14 in the cylinder 10 and from there. A flushing area 16 without any seal packing is formed in the front, and a seal packing 18 and a packing presser 20 are attached behind the flushing pipe 14. In this case, a sleeve 22 for smoothly guiding the flushing liquid to the outer peripheral surface of the plunger 12 is installed in the flushing region 16, and a portion of the sleeve 22 facing the flushing pipe 14 is attached as shown in FIG. As shown, through holes 24 are appropriately bored. Further, the length l of the sleeve 22 is preferably set longer than the maximum stroke displacement length of the plunger 12 so that the liquid-contacted portion of the plunger 12 does not enter into the seal packing 18. Furthermore, the gap between the outer circumferential surface of the plunger 12 and the inner circumferential surface of the sleeve 22, which forms the flushing region 16, is preferably set to a size such that the flushing liquid flows at a flow rate faster than the average speed at which the plunger 12 retreats. be. In addition, when setting the gap size between the plunger 12 and the sleeve 22, the discharge flow rate characteristics of the reciprocating pump for flush liquid supply, which will be described later, are also taken into consideration, but the flow rate should be at least twice the average speed at which the plunger 12 retreats. Most preferably, the flushing liquid is supplied at the same time.

On the other hand, the flash pipe 14 is connected to the check valve 2.
6, the reciprocating pump 28 for flushing liquid supply performs a flushing pump operation by reciprocating a plunger in the same manner as the main pump, and the suction side of the flushing pump 28 is connected to the discharge side of the flushing liquid supply reciprocating pump 28, which supplies flushing liquid as appropriate. Communicate with a supply source (not shown).

However, in the above-described reciprocating pump of this type, as a means for causing the reciprocating motion of the plunger 12, the rotational motion of the electric motor 30 is generally transferred to the crank device 32 via an appropriate speed reducer (not shown).
A configuration that transmits information is adopted. Therefore, in this embodiment, a coupling electrically connects the drive shaft 34 of the crank device 32 that drives the plunger 12 of the main pump and the drive shaft 38 of the crank device 36 that drives the flushing pump 28; The connection is made by a mechanical coupling means 40 such as a coupling, a chain, or a belt. In this case, the rotational phase difference is set to 180 degrees so that the flushing pump 28 has a discharge stroke in accordance with the suction stroke of the main pump. As a result, in the present invention, as shown in FIG. 3, the speed characteristics () during the reciprocating stroke of the plunger 12 of the main pump and the flushing liquid discharge amount characteristics () of the flushing pump 28 have a constant proportional relationship. . Therefore, the ratio of the amount of flushing liquid mixed in to the flow rate of the liquid handled by the main pump is always constant regardless of the pump rotation speed, and the amount of flushing liquid supplied increases or decreases in proportion to the magnitude of the plunger retraction speed. The concentration of the liquid handled by the main pump, that is, the slurry, can be controlled to always be constant.

According to the flushing operation during the suction stroke of the main pump in the reciprocating pump according to the present invention, the flushing liquid flows into the flushing region through the flush pipe 14 at a predetermined pressure, thereby removing solids attached to the plunger 12, for example. The material is washed away and solids are prevented from entering the seal packing 18. Thereby, stable and smooth operation of the main pump can be achieved without impairing the sealing functions of the seal packing 18 and the packing presser 20.

In particular, in the present invention, by employing a reciprocating pump as the flushing pump, the amount of flushing liquid can be maintained at a constant level, and a flushing liquid with high viscosity can be used. In addition, a reciprocating pump used as a flushing pump has the function of preventing backflow of flushing liquid, but a check valve can also be installed between the flushing pump and the flushing pipe. This makes it possible to reliably prevent backflow in the event that the pressure on the main pump side becomes excessive.Moreover, the flushing pump can be designed with pressure resistance comparable to the suction pressure of the main pump, making it easy to design. There are some advantages.

The sleeve 22 forming the flushing area 16 inside the cylinder 10 has through holes 24 formed uniformly in the circumferential direction for introducing the flushing liquid, as shown in FIG. , uniform flushing can be achieved over the circumferential surface of the plunger 12.

As is clear from the above-mentioned embodiments, the reciprocating pump according to the present invention sets the rotational phase difference between the main pump and the reciprocating pump for flush liquid supply to 180 degrees, and the flow rate of the flush liquid with respect to the flow rate of the liquid handled by the main pump is adjusted to 180 degrees. The main pump and the flushing liquid supply reciprocating pump are driven by a common drive so that the ratio of the mixed amount is always constant regardless of the pump rotation speed, and the amount of flushing liquid supplied increases or decreases in proportion to the magnitude of the plunger retraction speed. By connecting to the source, it is possible to achieve high precision concentration control of the main pump fluid, or slurry, which was difficult with conventional reciprocating pumps, without the need for a special control mechanism. It can be used selectively to achieve efficient flushing cleaning, and its practical effects are extremely large.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various improvements and changes can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of main parts showing an embodiment of the reciprocating pump according to the present invention, and Fig. 2 is a -
The line sectional view and FIG. 3 are waveform diagrams showing the speed characteristics of the plunger in the main pump of the pump of the present invention and the flushing liquid discharge flow rate characteristics of the flushing pump. 10...Cylinder, 12...Plunger, 14
... flushing pipe, 16 ... flushing area, 18 ... seal packing, 20 ... packing presser, 22 ... sleeve, 24 ... through hole, 26 ...
...Check valve, 28...Flushing pump, 30...
...Electric motor, 32, 36...Crank device, 3
4, 38...drive shaft, 40...coupling means.

Claims (1)

[Scope of utility model registration request] A flushing pipe is provided in the cylinder part that supports the plunger that performs the main pump operation, behind the maximum retracted position of the plunger where it comes into contact with the liquid handled by the pump, and a flushing area is formed on the front side of the pump chamber from this flushing pipe. In a reciprocating pump configured such that a gasket is provided on the rear drive source side and a reciprocating pump for flushing liquid supply is connected to the flushing pipe so that the flushing liquid cleans the surface of the plunger, the main pump and the flushing liquid supply are connected. Rotational phase difference of reciprocating pump for
180°, and a check valve to prevent backflow of the flush liquid is installed in the connection pipe between the flush pipe and the reciprocating pump for supplying the flush liquid, and the ratio of the mixed amount of the flush liquid to the flow rate of the liquid handled by the main pump is The main pump and the flushing liquid supply reciprocating pump are connected in common so that the dilution rate (dilution rate) is always constant regardless of the pump rotation speed, and the amount of flushing liquid supplied increases or decreases in proportion to the magnitude of the plunger retraction speed. A reciprocating pump characterized by being connected to a drive source.