RU2267659C2 - Method of continuous delivery of steam to water main at flow rate of water variable in time within wide range and device for realization of this method - Google Patents

Abstract

FIELD: continuous delivery of steam to water main at flow rate variable in time within wide range.

SUBSTANCE: proposed method includes acceleration of liquid in active nozzle, creating of rarefaction zone, delivery of steam to rarefaction zone, maintenance of constant pressure in rarefaction zone by changing the angle of inclination of nozzle walls relative to main flow of water at additional change of form of water jet section from round to ellipsoidal. Device proposed for realization of this method includes intake chamber and active nozzle in form of two half-nozzles mounted on hinges; clearance along parting line is closed by sealing plate secured to half-nozzle; besides that, flats are made on outer surface of half-nozzles along parting line over which sealing plates slide and may be pressed to them.

EFFECT: possibility of preheating water.

3 cl, 4 dwg

Description

The invention relates to the field of power engineering and can be applied in any sectors of the economy that have piped water systems and steam sources in operation. In particular, the invention relates to methods and devices for continuously introducing steam into a water stream for heating it to a required temperature range in heat supply systems, hot water supply and water treatment systems to ensure their operability in a wide range of heated water flow rates, diameters of piping systems, steam pressures.

Known inkjet apparatuses for introducing gaseous media and steam into a fluid stream are described, for example, in the book of Sokolov E.Ya., Singer N.M. "Inkjet apparatus". Ed. 2nd, M., "Energy", 1970. The operation of the apparatus is based on the phenomenon of ejection by a flooded stream of a working medium (liquid or gas) of a passive medium (also liquid or gas). For example, pages 251-270 describe a mixing jet water heater, the working medium of which is water, and the injected medium is steam, which heats the water during condensation. The heater consists of an active nozzle, a receiving chamber, a mixing chamber and a diffuser.

The advantage of the analogue is the simplicity of design, as well as the simplicity of manufacture. A disadvantage of the analogue is a narrow range of water flow rates, in which its stable operation can be ensured. The reason for this is that the active nozzle is made of precisely specified sizes, calculated for a certain range of water flow rates at given water and steam pressures. This narrows the operational capabilities of such devices, for example, with peak loads in hot water systems, with seasonal fluctuations in the consumption of water consumers.

There is a whole class of inventions that improve the operation of inkjet devices, for example, No. 2041404, 2046220, 2061912, 2059893, 2059894, Cl.6 F 04 F 5/4; 1809671-1809673, a.s. 1044839, 1806296 - 1806300, Cl. 5 F 04 F 5/4; but. from. 901655, Cl. F 04 F 5/16; A.S. 892033, Cl. F 04 F 5/14; but. from. 787736, Cl. F 04 F 5/20; A.S. 787735, Cl. F 04 F 5/02; but. from. 785558, Cl. F 04 F 5/14; A.S. 403880, Cl. F 04 F 5/4; A.S. 415411, Cl. F 04 F 5/14; Clause 215187, Cl. 6 F 04 F 5/02. But all these devices do not provide a continuous input of steam into the water line to heat the current flow rate of water, continuously changing over a wide range.

Also known are jet devices in which, to change the ratio of flows of active and passive gas (liquid), a conical rod (needle) is introduced into the active nozzle, which moves tolerably to the nozzle (Schukin V.K., Kalmykov II, "Gas-jet compressors ", Mashgiz, M., 1963).

The disadvantages of the analogue are the asymmetric (lateral) supply of the working fluid (gas), which reduces the stability of the apparatus during operation in transient and extreme conditions, as well as a narrow range of flow control (usually ± 15%).

The creation of devices of this class with a wider range of flow control is inevitably associated with both increased requirements for the accuracy of the manufacture of the apparatus and an increase in the length of the cantilevered needle, which can lead to its vibrations and stalls. This does not allow for the continuous introduction of steam into the water main for heating the current flow rate of water, which varies over a wide range.

The closest technical solution to the claimed is a patent of the Russian Federation No. 2198323, Cl. 7 F 04 F 5/08, priority 06/21/2000, published 02/10/2003, adopted as a prototype by the method and prototype by the device.

According to p.2198323, in part of the method, the active liquid is dispersed with a decrease in pressure, a rarefaction zone is formed in the pipeline of the water line and continuous steam is supplied to the rarefaction zone. The technical solution proposed in the prototype provides continuous input of low-pressure steam with varying parameters into the high-pressure water main to increase water temperatures and utilize steam.

But this solution has a limitation when used in conditions where the flow rate of heated water varies widely. So, for example, at steam pressures lower than the water pressure in the line, the permissible range of variation in water flow at which steam can be introduced into the water stream is ± 4%, and at steam pressures of large water pressures ± 15%, which is clearly not enough, especially during peak water analyzes in hot water supply systems, when the water flow rate changes several times (for example, from 100 t / h to 1100 t / h).

Such changes in water flow lead to significant changes in pressure in the rarefaction zone and, as a consequence, to the possibility of realizing steam supply with critical and supercritical velocities to the rarefaction zone, which are accompanied, as practice has shown, by unacceptable hydraulic shocks and vibrations of the prototype device and highways. On the other hand, the geometry of the active nozzle, as is known, is calculated by the value of the lower boundary of the range of water consumption and, accordingly, when water consumption exceeds this boundary several times, there is an increase in the hydraulic resistance of the nozzle to values that limit the possibility of using the prototype.

SUMMARY OF THE INVENTION

The technical problem solved by the claimed invention is the provision of continuous input of steam into the water line to heat the current water flow over a certain temperature range with a continuous change in time over the flow of heated water over a wide range.

The problem is solved in that in a highway with a time-variable flow rate of water, the liquid is accelerated with decreasing pressure, for example by installing an active nozzle, and a rarefaction zone is formed with a pressure value lower than the pressure of the steam source, while the pressure in the rarefaction zone is equal to critical part of the active nozzle, and continuous steam supply is carried out in the rarefaction zone, while during the steam supply, the pressure in the rarefaction zone (statistical pressure at the nozzle exit) is kept constant m changes the inclination angle of the active nozzle wall relative to the main water flow, further changing the shape of the water jet with a circular cross section into an elliptical.

The essential features of the invention:

- Acceleration of fluid in the active nozzle and the creation of a rarefaction zone;

- Steam supply to the rarefaction zone;

- Maintaining a constant pressure in the rarefaction zone when changing the flow rate of heated water by changing the angle of inclination of the walls of the active nozzle relative to the main flow of water;

- Additionally, the shape of the cross section of the water stream changes from round to elliptical.

The signs "acceleration of the liquid in the active nozzle and the creation of a rarefaction zone, and the supply of steam to the rarefaction zone" are common, the rest are distinctive.

Figure 1, 2 and 3 presents the design of the steam ejector device that ensures the implementation of the processes inherent in the proposed method.

Figure 4 shows a variant of the drive mechanism of the sliding half-nozzles of the vapor ejector device.

The following is indicated in the drawings:

1. Supply water line.

2. Confuser.

3. The hinge.

4. Half-nozzle.

5. The gap between the half-nozzles.

6. The receiving chamber.

7. Thrust half-nozzle.

8. Seal traction.

9. Diversion water line.

10. Half-nozzle.

11. The cheek.

12. The sealing plate.

13. Lever.

14. The slider.

15. The helm.

16. The core is constricting.

17.screw.

18. Rib.

19. Pressure take-off pipe.

20. Pressure gauge (pressure sensor).

21. The working plane of the gap seal half-nozzles.

The device includes an active nozzle consisting of a confuser 2 and half nozzles 4 and 10. Half nozzles are mounted on cylindrical joints 3 fixed by welding on the confuser. On the outer surface of each half nozzle, ribs 18 are made with grooves to which rods 7 are passed through a releasing connection through the housing of the receiving chamber 6. To seal the rods in the receiving chamber, stuffing boxes are used 8. The half nozzles are formed by cutting an axisymmetric nozzle, for example, along the meridional section. The gap 5 along the dissection line is hermetically sealed with a sealing plate 12 (for example, made of fluoroplastic), attached to the cheek 11 (with glue, rivets). The cheek is made in the form of a plate along the entire length of the gap and fastened, for example, by welding, to the half nozzle 10. Along the line of the connection of the half nozzles on their outer surface along the entire length of each half nozzle there are working planes (flats) 21 along which the sealing plates slip and are pressed during operation 12.

To create the angular deviation of the half-nozzles, the movement of the rods can be carried out by various mechanisms. An embodiment of the link drive mechanism using a screw-nut transmission is given in FIG. 4. Such a mechanism consists of levers 13, a screw 17 having a right and left thread, a slider 14. To increase the rigidity and efficiency of sealing the gap between the half nozzles, the cheeks are pulled together by a rod 16.

A water supply line 1 is connected to the input of the confuser and water is supplied. An outlet water line 9 is connected to the output of the receiving chamber.

The operation of the device is as follows. Water under pressure along the supply line 1 enters the entrance to the confuser 2 and then to the area bounded by the half-nozzles 4 and 10. In the half-nozzles, the water accelerates to certain speeds, and a high-pressure jet is formed at the outlet with a pressure value determined from the Bernoulli interval less than steam pressure. The jet structure of the flow is maintained along the entire length of the receiving chamber 6 and the rectilinear section of the discharge line 9 connected to it over 15 ... 40 diameters of the line, while a rarefaction zone is formed in the space between the stream, the housing of the receiving chamber and the wall of the discharge line close to to the pressure in the stream, which ensures the introduction of steam into the water line (the direction of steam supply is given in figure 2). When changing the flow rate of water in the supply water line 1, in accordance with the continuity equation, a corresponding change in the flow velocity of the water in the half nozzles and the associated change in pressure in the rarefaction zone occurs.

The indicated pressure, recorded, for example, by a manometer 20 or a pressure sensor, is taken at the level of the half-nozzle cut using tube 19. Using the rods 7, the angle of inclination of the half-nozzles 4 and 10 is changed with respect to the direction of the main flow (to the axis of the half-nozzles), and therefore changes as the critical sectional area of the water nozzle and the pressure loss in it, which allows you to effectively control the pressure in the rarefaction zone and keep it constant. The position of the half-nozzles with a changed angle of inclination is shown by dashed lines. In addition, with a change in the angle of inclination of the half-nozzles, the shape of the flowing water jet changes, which becomes elliptical from a round one and accordingly increases the ejection coefficient (with the same jet momentum), and heat transfer processes are accelerated due to an increase in the surface of the water jet. In this case, the vapor pressure is set based on the required temperature of heating the water, and the pressure in the rarefaction zone is determined from the condition of ensuring the ratio of these pressures so that critical and supercritical velocities of the steam supplied to the receiving chamber are excluded.

Management of the opening angle of the half-nozzles can be carried out using a helical gear with levers (figure 4). When the steering wheel 15 rotates clockwise, the half-nozzles 4 and 10 are evenly opened, and when the steering wheel is rotated counterclockwise, the nozzle cross section is narrowed and the angle of inclination of the half-nozzles to the main flow is changed. To automate the control process, the screw 17 can be activated from an electric drive by a signal from a pressure sensor 20 with the implementation of a control circuit with negative feedback. 4, the dotted line shows the position of one of the levers 13 in the extreme positions.

The features of the invention are:

- receiving chamber;

- active nozzle made in the form of half nozzles mounted on hinges;

- the gap along the connector line is closed by a sealing plate attached to the half nozzle;

- flats are made along the line of the connector along which the sealing plates slide when moving with the possibility of pressing in the work.

The sign "receiving chamber" is common, the rest are distinctive. Thus, the proposed method and device have an inventive step, since the totality of the features of this method and device determines a new property that gives the required technical effect: it provides continuous steam input into the water main to heat the current water flow for a certain temperature range with a continuous change in water flow over time over a wide range. In addition, the steam supply mode with critical and supercritical flow velocities and associated vibrations and hydraulic shocks are eliminated, hydraulic losses of water pressure are reduced, and the ejection coefficient is increased.

For a water pipeline system with a nominal diameter of 100 mm, with a water flow rate varying in the range of 10 ... 40 t / h, an excess working pressure of water of 0.3-0.35 MPa, a vapor pressure of 0.05-0.02 MPa, in order to continuously heat water at 20-30 ° C, a steam ejection device was also designed in accordance with the invention. The device is made with a regulating area of the active nozzle in the range of 95 ... 490 mm ² , which ensures continuous steam injection with a flow rate of up to 2.2 t / h. The prototype confirmed its effectiveness and efficiency.

Claims (2)

1. A method of continuously supplying steam to a water main with a variable time flow of water over a wide range, including accelerating the liquid in the active nozzle, creating a rarefaction zone, supplying steam to the rarefaction zone, maintaining a constant pressure in the rarefaction zone by changing the angle of inclination of the nozzle walls relative to the main water flow, characterized in that it additionally simultaneously changes the shape of the cross section of the water stream from round to elliptical. 2. A device for continuously supplying steam to a water line containing a receiving chamber and an active nozzle in the form of two half nozzles mounted on hinges, the gap along the connector line being closed by a sealing plate attached to the half nozzle, characterized in that along the outer surface of the half nozzles along connector lines are made flats along which the sealing plates slide when moving with the possibility of pressing in the work.

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