RU2426916C1 - Adjustable ejector - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: ejector consists of case of active nozzle, of receiving chamber, of mixing chamber and of a diffuser. The case of adjustable ejector is equipped with supplying branch of active medium supply. In the axial channel of the case there is installed a mechanism of size adjustment consisting of a needle connected with a drive mechanism through a screw pair; the drive mechanism consists of a stepper motor. The mechanism of size adjustment consists of a needle set asymmetrically to an axial channel and connected with the screw pair; the latter is connected to the stepper motor via a coupling. The stepper motor is secured on a flange of a head holder arranged in the axial channel of the case on thread. The mechanism of size adjustment consists of a driving gear connected with the driving gear and the coupling; the mechanism with the coupling is secured on the case with a cantilever.

EFFECT: control over adjustment elements of ejector; simultaneous gradual change of position of three interconnected parameters of ejector subordinate to common algorithm for stable operation of device.

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Description

The invention relates to inkjet technology and can be used in the oil and gas industry, in particular, to obtain aerated liquids, two-phase foams.

Known inkjet apparatus [A.S. USSR No. 909349, F04F 5/16, publ. 02.28.82], containing a receiving chamber in which are installed, with the possibility of axial movement of the active nozzle, the control and displacement cameras, as well as a diffuser. The control chamber is equipped with a heat-sensitive element, the ends of which are fixed on the active nozzle and the wall of the control chamber, equipped with a nozzle for supplying and discharging the coolant.

The disadvantage of this device are:

- low accuracy of adjustment of the inkjet apparatus due to the inertia of the system, which consists in the use of a thermosensitive element in the kinematics of the axial movement of the active nozzle;

- a change in only one component, namely, only the axial movement of the active nozzle does not allow optimizing the operation of the inkjet apparatus, which is reflected in the standard dependencies of the calculation of inkjet apparatuses.

Analysis of technical solutions in this technical field showed that the ejector design is known (see AS No. 1710859, F04F 5/48, publ. 02/07/92. Bull. No. 5), in which the transverse dimensions of the mixing chamber and diffuser are changed. The mixing chamber is spring loaded relative to the active nozzle and is mounted with the possibility of axial movement. However, a change in these sizes occurs spontaneously, without defining an algorithm.

The known design of the jet pump (see AS No. 1343118, F04F 5/02, publ. 07.10.87, Bull. No. 37), adopted as a prototype.

The device consists of a receiving chamber, a displacement chamber, a diffuser, an active nozzle in the receiving chamber with a control needle connected to the drive, inlet pipes of the active and passive medium.

The device operates as follows.

The active medium is fed to the active nozzle with the output of the jet into the mixing chamber, where the passive medium is sucked. In the diffuser, the kinetic energy of the mixture of media is partially converted into potential energy. By moving the needle in the axial channel of the active nozzle due to the drive, on the outer surface of the inlet pipe, the flow of the active medium through the active nozzle is controlled, thereby controlling the total flow of the mixture of media to the consumer.

The main disadvantage of the above devices is that they do not have conditions that provide for the simultaneous change of three interconnected parameters of the ejector: the cross section of the displacement chamber, the cross section of the axial channel of the active nozzle, the distance from the nozzle to the displacement chamber.

The choice of one or another diameter of the nozzle chamber and, accordingly, the diameter of the displacement chamber is determined by the necessary degree of aeration, the pressure of the mixed flow. Changing only one of the parameters does not lead to the expected result.

The technical result that can be obtained by implementing the invention is as follows:

- the ability to control the regulating elements of the ejector to obtain aerated liquid at the outlet of the diffuser, with specified technological parameters;

- the ability to simultaneously smoothly change the position of three interconnected parameters of the ejector with submission to a single algorithm for stable operation of the device;

- the use of stepper motors to change the technological and structural parameters of the ejector elements, with the control of their inclusion from the microprocessor unit, for the purpose of smooth regulation of the main elements of the ejector.

The technical result is achieved in that the adjustable ejector contains a receiving chamber, a mixing chamber, an active nozzle, a diffuser, inlet and outlet pipes, a regulating needle, a needle drive mechanism, and the device is equipped with a nozzle holder installed in the axial channel of the housing, a drive mechanism including a flange with the gear rim kinematically connected with the gear of a stepper motor equipped with a coupling, the control needle is mounted asymmetrically in the nozzle holder and is equipped with a drive in the form of a stepper motor the holder mounted on the nozzle holder flange, the axial channel of the diffuser is equipped with a control needle connected to the axial movement mechanism, including a stroke control mechanism in the form of a stepper motor mounted on the diffuser, and the axial channel of the supply pipe is hydraulically connected through windows in the nozzle holder body with its internal chamber, the outlet pipe is installed on the outside of the diffuser with the possibility of hydraulic connection of its axial channel with the axial channel of the diffuser above the control mechanism l, and stepper motors for regulating the axial movement of the needle, the active nozzle, the axial movement of the nozzle holder and the axial movement of the diffuser are connected to the microprocessor and are subject to a single control algorithm.

The design of the device in section is shown in the drawing.

The drawing in section shows the device in the position of the parts for conducting the ejection process.

The ejector comprises a housing 1, an active nozzle 2, a receiving chamber 3, a mixing chamber 4 and a diffuser 5. The housing 1 is equipped with a supply pipe 6 for the active medium and a pipe 7 for supplying a passive medium and a discharge pipe 8. A dimensioning mechanism 9 is installed in the axial channel of the housing 1 mixing chamber 4, which consists of a needle 10 connected through a screw pair 11 with a drive mechanism 12, consisting of a stepper motor 13.

The size control mechanism of the active nozzle 2 consists of a needle 14 mounted asymmetrically to its axial channel and connected to a screw pair 15. The screw pair 15, in turn, is connected through a clutch 16 to a stepper motor 17, which is mounted on a flange 18, supported by a flange 19 of the nozzle holder 20 installed in the axial channel of the housing 1 on the thread.

The size control mechanism of the receiving chamber 3 consists of a driven gear 21, a nozzle holder 20 kinematically connected to the drive gear 22, which, through the coupling 23, is connected to a stepper motor 24 mounted on the console 23 connected to the housing 1.

Windows 26 are made in the body of the nozzle holder 20, hydraulically connecting the axial channel 27 of the inlet pipe 6 with the inner chamber 28 in the nozzle holder 20.

Work adjustable ejector.

For the normal operation of the ejector, it is necessary to strictly observe the alignment of the mixing chamber and the active nozzle, as well as maintaining the distance from the end of the active nozzle to the end of the cylindrical part of the mixing chamber in the calculated limits.

In accordance with the existing dependences (see Sokolov) for the calculation of the main structural parameters, they must be divided according to the following technological parameters - the degree of aeration, the pressure of the mixed stream at the outlet, as well as the necessary degree of aeration of the stream.

Based on this, the movement of the moving parts of the ejector is subject to a single algorithm.

The ejector works as follows.

The active medium through the inlet pipe 6 and the window 26 in the body of the nozzle holder 20 enters the inner chamber 28 and then passes through the active nozzle 2, and then enters the receiving chamber 3, into which the passive medium (gas) is supplied through the inlet pipe 7. The active medium is mixed with a passive medium and enters the mixing chamber 4, then in the diffuser 5, the static pressure of the mixture rises, and the mixture is supplied to the consumer through the outlet pipe.

Adjustment to the operational parameters of the mixing chamber 3 is carried out by mechanical adjustment of the sizes of the mixing chamber 3, i.e. by changing the distance between the end face of the nozzle holder 20 and the end face of the mixing chamber 4.

Adjustment to the operating parameters of the active nozzle 2 is carried out by changing its cross-sectional area by introducing the needle into the axial channel 14. The input is carried out by applying a signal to the stepper motor 17, which during operation transmits torque through the clutch 16 to the needle 14, which is inserted - moves towards the active nozzle 2 with access to the axial channel.

The flow rate and the feed rate of the mixture into the diffuser 5 are changed by introducing into the axial channel a needle 10 connected through a screw pair 11 with a drive mechanism 12 and a stepper motor 13.

The movement of the nozzle holder 20 in the axial channel of the housing 1 is carried out by transmitting torque to the drive gear 22 from the stepper motor 24.

Rotate the driven gear 21, rigidly connected with the nozzle holder 20, which leads to its axial movement in the axial channel of the housing 1. During the movement of the nozzle holder 20, there is a constant connection of the axial channel 27 of the inlet pipe 6 through the window 26 with the inner chamber 29 in the nozzle holder 20.

For the normal operation of the ejector, it is necessary to observe the alignment of the channels of the active nozzle of the displacement chamber and the diffuser, and it is also necessary to maintain the optimal distance from the end of the active nozzle to the entrance to the mixing chamber.

This distance is determined by:

1 = 1 ÷ 1.5 of the diameter of the axial channel of the mixing chamber.

The ejector control algorithm is built in accordance with existing dependencies that determine the stable nature of the work.

The choice of the diameter of the axial channel of the active nozzle and, accordingly, the diameter of the mixing chamber is determined by the required degree of aeration and the satisfaction of the mixed flow at the outlet of the diffuser.

To dynamically change the parameters in an adjustable ejector, an axial displacement mechanism drive from a stepper motor is used. Controlling the operation of stepper motors uses a microprocessor.

The algorithm is based on the following data.

The pressure, productivity and coefficient of ejector ejection is determined by the diameter of the axial channel, the active nozzle and the mixing chamber, as well as the distance from the end of the active nozzle to the flow inlet to the mixing chamber.

Formulas by which you can determine the parameters of the ejector: - volumetric coefficient of ejection (the ratio of the volumes of the ejected medium to the working fluid).

U ₀ under the condition P _with ≥1 kg / cm ² is determined by the formula

where ΔP _p = P _p -P _r ;

ΔPc = P _c -P _r ;

P _p is the pressure of the ejection (working) stream, i.e. the pressure of the developed unit at the receiving pipe of the ejector, kg / cm ² ;

P _r is the pressure of the ejection flow (pressure in the loop or developed by the compressor), kg / cm ² .

P _{with the} pressure of the mixed stream at the outlet pipe of the ejector, kg / cm ² .

The ratio of the cross-sectional areas of the mixing chamber f ₃ and the active nozzle f _p1 can be expressed by the following condition:

Standard dependence of the parameters of the ejector

приводит к увеличению коэффициента эжекции и снижению давления смеси Р_с и наоборот.With a constant value of the pressure of the ejection (working) flow P _p increase the ratio

leads to an increase in the ejection coefficient and a decrease in the pressure of the mixture P _s and vice versa.

The stability of the ejector is maintained at values determined by the empirical formula:

P _c = 0.3 ÷ 0.55P _p

Enter parameters:

R _f - pressure of the working fluid at the inlet to the nozzle holder chamber, kg / cm ² ;

R _g - gas pressure at the inlet to the mixing chamber, kg / cm ² ;

q is the flow rate of the working fluid, l / s;

P _o - the required pressure at the outlet of the ejector diffuser, kg / cm ² ;

λ is the required degree of aeration;

l ₁ is the step of changing the cross section of the axial channel of the active nozzle, mm;

l ₂ is the step of changing the cross section of the mixing chamber, mm;

l ₃ is the step of changing the distance from the end of the active nozzle to the mixing chamber, mm;

µ - nozzle flow coefficient equal to 0.9;

d _sn ; d _pr ; L _n - initial (initial) values of the diameter of the active nozzle, the diameter of the mixing chamber and the distance from the end of the active nozzle to the mixing chamber.

Calculate:

1. The diameter of the axial channel of the active nozzle, d _sn :

2. The diameter of the mixing chamber, d _pr

The distance from the end face of the active nozzle to the mixing chamber L _n = d _prf (1 ÷ 1.5).

Claims (1)

An adjustable ejector containing a receiving chamber, a mixing chamber, an active nozzle, a diffuser, inlet and outlet nozzles, a regulating needle, a needle drive mechanism, characterized in that the device is equipped with a nozzle holder installed in the axial channel of the housing, a drive mechanism including a flange with a gear ring kinematically connected with the gear of a stepper motor equipped with a coupling, the control needle is mounted asymmetrically in the nozzle holder and is equipped with a stepper motor drive mounted on a the nozzle holder, the axial channel of the diffuser is equipped with a control needle connected to the axial movement mechanism, including a stroke control mechanism in the form of a stepper motor mounted on the diffuser, and the axial channel of the supply pipe is hydraulically connected through windows in the body of the nozzle holder with its internal chamber, the outlet pipe is mounted on the outer side of the diffuser with the possibility of hydraulic connection of its axial channel with the axial channel of the diffuser above the mechanism for regulating the stroke of the needle, and stepper motors regulate The axial movement of the needle, the active nozzle, the axial movement of the nozzle holder and the axial movement of the diffuser are associated with a microprocessor and are subject to a single control algorithm.