RU1788341C - Hydraulic elevator - Google Patents

Abstract

SUMMARY OF THE INVENTION: a pipe for supplying a passive medium is made coaxially with an active nozzle. The passive medium supply pipe is provided with a nozzle, the outer surface of which is made in the form of a diverging cone, the inlet of which is located in the nozzle exit plane, the output is in the mixing chamber, the external diameter of the nozzle inlet section is equal to the external diameter of the passive medium supply pipe. 2 ill.

Description

The invention relates to inkjet technology and can be used in mining, mining and geological, energy and a number of other industries. An ejector comprising a housing in which an active nozzle connected to a nozzle, a mixing chamber and a diffuser is known is known. The fitting and nozzle can be connected by a bellows. The cleaned working fluid enters the active nozzle, where it accelerates, acquiring kinetic energy, which is expended in the mixing chamber and diffuser to pump the passive medium. The specified device ensures the operation of the ejector at low cost, for example, in cryogenic plants.

One of the disadvantages of this ejector is its low productivity and efficiency.

The closest in technical essence to the proposed hydraulic elevator and taken as a prototype is a known unregulated jet pump consisting of an active annular nozzle, a central passive nozzle, a working chamber, a mixing chamber and a diffuser. An active annular nozzle is formed between the confuser of the working chamber and the central passive nozzle. The taper angle of the confuser of the working chamber is 12 °. The central nozzle is connected to a pipe for supplying a passive medium. At the end of the mixing chamber there is a diffuser, which, like the mixing chamber, has a slightly shorter length than hydroelevators with a central active nozzle.

This type of inkjet apparatus has the same disadvantages as installations with a centrally located nozzle, but here the shape of the working chamber has practically no effect on the magnitude of the losses, since the mixing of the flows takes place directly in the mixing chamber.

The main energy loss leading to low efficiency in any type of inkjet apparatus remains the so-called impact loss associated with the mixing of two joint flows with different initial velocities.

The loss on impact during mixing is equal to the power difference between the kinematic energies of the flows before and after mixing AE pro VJ

00

00

with

N

proportional to the square of the difference in flow velocities at the beginning of mixing

Ap 1 GPG G Gp + GH

(Wp1-whl)

(1)

where Gp is the mass flow rate of the active medium flow;

He is the mass flow rate of the passive medium;

wpi is the flow rate of the active medium in the output section of the active nozzle;

WH1 is the flow rate of the passive medium in the inlet section of the mixing chamber.

Since the speeds wpi and WH1 are sharply different from each other, the losses due to the mixing of the flows of the active and passive medium are very large and are one of the main reasons for the narrow range of applications of jet devices.

A feature of the jet pump, taken as a prototype, is that the nature of the distribution of axial velocities over the cross section of the mixing chamber of this device is fundamentally different from the diagram of the velocities of the mixture of media in the mixing chamber of hydraulic elevators with a central active nozzle. Impact losses remain, only a significant part of them is transferred from the working chamber to the mixing chamber.

The aim of the invention is to increase the performance of the elevator and its efficiency.

This is achieved by the fact that in the inventive device comprising an active nozzle, a passive medium supply pipe arranged coaxially with the active nozzle, a working chamber and a mixing chamber, a diffuser, a passive medium supply pipe is equipped with a nozzle, the outer surface of which is made in the form of a conical flow a cone, the inlet of which is located in the nozzle exit plane, and the outlet is in the mixing chamber, wherein the outer diameter of the nozzle inlet section is equal to the outer diameter of the passive medium supply pipe.

Figure 1 shows a schematic diagram of a hydraulic elevator; Fig. 2 is a graph of the absolute pressure in the mixing chamber along the length of the mixing chamber.

The hydraulic elevator consists (see Fig. 1) of a pipeline 1 supplying an active medium (flow rate Qa), at the end of which an active nozzle 2 is located. A pipeline 3, which is used to supply a passive medium (flow rate Qn, passes through the pipeline 1 and the active nozzle 2) ) At the end of the pipeline 3, nozzles 4 are made coaxially with the active nozzle 2, the outer surface of which is made in the form of a conically diverging cone, and the outer diameter of the inlet section of the nozzle dH is equal to the outer diameter of the passive medium supply pipe.

Its second end, equal to the diameter dH

nozzles 4 are placed in the mixing chamber 5,

which is connected coaxially with the diffuser 6,

and it connects to the outlet pipe 7. The pipe 3 with the nozzle 4 located at the end 4 forms an annular gap 8 with the active nozzle 2. The working chamber 9 hermetically connects the pipe 1, ending with the nozzle 2, the passive supply pipe 3 media and mixing chamber 5.

The active medium passes through the pipeline 1 and enters the nozzle 2 into the annular slot 8. The jet exits the annular gap 8, passes the working chamber 9 and enters the mixing chamber 5. The jet exiting the active nozzle has a central opening angle uniquely determined by the hydraulic elevator parameters determined by the empirical formula

% mp 2.1 K APPV (d2 d2), deg.

(2)

where dp is the outer diameter of the active nozzle

2 in its output section;

K is a correction factor slightly different from unity;

DPR - increase in the pressure of the active medium in front of the active nozzle above the pressure of the passive medium in the mixing chamber.

In the proposed design, the angle of expansion of the outer surface of the nozzle 4 a (see Fig. 1) is made equal to the angle Ostr, so that there is no separation of the jet

active medium from the surface of the nozzle 4. The continuous sliding of the jet of active medium over the surface of the nozzle 4 along its entire length allows the jet of active medium to form to the point of entry into the chamber

mixing 5 of the passive medium, as a result of which the jet has a greater load-bearing capacity than a conventional jet. As a result of the interaction of the forces of turbulent friction, which causes

vortices of the active and passive media in the initial section of the mixing chamber 5, a lower pressure is established in the mixing chamber 5 than the pressure of the passive medium. Passive sucking in

environment pipeline 3.

Studies show that the minimum pressure in the mixing chamber 5 will be in section I-I (see figure 1), located at a distance of approximately equal to the diameter

the dx mixing chamber, counting from the beginning of the mixing chamber (see Fig. 2). Starting from a cross section with a minimum pressure located at a distance d from the beginning of the mixing chamber, an increase in pressure is observed, it reaches atmospheric pressure and its further increase. Therefore, the second end of the nozzle 4 is located in cross section with minimal pressure. This increases the pressure drop at the ends of the pipeline 3 supplying the passive medium and contributes to an increase in the overall efficiency of the hydraulic elevator.

The proposed device will work efficiently not only when the outlet section of the nozzle 4 (see Fig. 1) is placed at a distance from the inlet section of the mixing chamber 5 equal to its diameter d ". but also with the obligatory fulfillment of the condition

S3

M &

(3)

where 8c is the sum of the cross-sectional area of the jet of the active medium and the cross-sectional area of the outer surface of the nozzle 4 in the Ill-Ill plane. When designing a hydraulic elevator, one of the main geometric dimensions of the flow part will be the size of the nozzle 4. Assuming that the diameter dH can be set (from conditions, for example, ensuring the required flow rate of a passive medium or an ejection coefficient, the average particle size of a solid during transportation of pulp, module, and other parameters) , for the flow of the active medium, the length of the nozzle 4 LI + d and the angle He will remain most important. The angle He Ostr is determined from equation (2), and the length I is determined from equations (2) and (3), taking into account that

dH dH + 2 (l + dK) tg Acute,

(4)

where dH is the diameter of the output section of the outer surface of the pipe 2. From equation (4) we have

, jdH + 2 (1 + dQtg Qcmp

(5)

Substituted the value of S3 from the equation

(5) in expression (3) and the sign Ostr. we can determine the maximum possible value of 1. °

In the mixing chamber 5, the kinematic energies of the active and passive media are aligned. Next, the mixed flow passes through the diffuser b, where a certain part of the kinetic energy is converted into potential energy, the pressure of the mixture of media increases, and then the flow enters the discharge pipe 7.

Thus, the inventive device allows to increase the carrying capacity of the jet of the active medium and productivity, which generally increases the efficiency of the hydraulic elevator.

Claims (1)

SUMMARY OF THE INVENTION A hydraulic elevator comprising an active nozzle, a passive medium inlet nozzle made coaxially with the active nozzle, a working chamber, a mixing chamber and a diffuser, characterized in that, in order to increase the efficiency, the passive medium supply pipe is provided with a nozzle, the outer surface of which is made in the form flow rate of a cone whose inlet is located in the nozzle exit plane and the outlet is in the mixing chamber, while the outer diameter of the nozzle inlet section is equal to the outer diameter of the supply pipe passive environment.