RU2316680C2 - Jet-mixing gas-heater of liquid - Google Patents

Abstract

FIELD: the invention refers to heating engineering.

SUBSTANCE: the jet-mixing gas-heater has an active nozzle, a receiving chamber, a chamber of preliminary mixing, a pipeline of feeding liquid into the chamber of preliminary mixing with an arrangement of forcing liquid connected with the system of shutting off bolts: a suction socket with the input into the active nozzle, a forcing socket with the chamber of preliminary mixing or with the suction socket with the output part of the heater, and with forcing socket with the chamber of preliminary mixing or the suction and the forcing sockets are connected with the chamber of preliminary mixing. In the body of the chamber of preliminary mixing there are tangential nozzles and on the inner surface blades are installed.

EFFECT: heating of liquid.

2 dwg

Description

The invention relates to the field of power engineering and can be applied in any sectors of the national economy for heating a liquid with steam introduced into a liquid stream, in particular, a heat supply system, hot water supply and water treatment system.

In industry, in technological processes, there are related sources of steam of variable parameters with varying pressures, temperature and flow rate, for example, evaporative cooling systems of open-hearth furnaces, convectors, exhaust steam from steam engines, which is used either partially or not at all, but is discharged into the atmosphere. In terms of energy, these sources have significant reserves of thermal energy, which is advisable to use, for example, for heating water in highways with the use of condensate after boiler installations. But most often it turns out that the pressure in the water mains can be either higher or lower than the pressure of the steam source, which creates difficulties in using such sources.

The present invention is aimed at creating a device that solves this problem, that is, providing heating of the current liquid flow rate with steam when changing the input parameters of the steam (pressure and flow rate) in a wide range.

For heating a liquid with steam, jet devices of the classical scheme are known, which are described, for example, in the book of Sokolov E.Ya. and 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 vapor) of a passive medium (also liquid or vapor). 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 such devices is the simplicity of design, as well as the simplicity of manufacture. There is a whole class of inventions that improve the operation of inkjet devices, for example: p.2125187, cl. 6 F04F 5/02; but. p. 1044839, class F04F 5/14; p. 2041404, 2046220, 2061912, 2059893, 2059894, cl. 6 F04F 5/4; 1809671-1809673, 1806296 - 1806300, cl. 5 F04F 5/4; A.S. 901655, cl. F04F 5/16; but. p. 403880, class F04F 5/4; A.S. 787735, class F04F 5/02. But all these devices are not applicable when changing in a wide range of input parameters of the steam, a significant difference in pressure at the source of steam and in the water mains. In addition, with increased steam flow rates, a two-phase flow structure is formed in the water main with sizes of steam inclusions close to the dimensions of the pipe, causing shock-vibration impact on the pipeline systems, which is unacceptable.

The closest technical solution to the claimed is a patent of the Russian Federation No. 2198323 C2, class. 7 F04F 5/08, priority 06/21/2000, published in bull. No. 4 02/10/2003, adopted as a prototype.

Taken as a prototype, a device for continuously supplying steam to the water main contains an active nozzle in which the heated water is accelerated with decreasing pressure, a receiving chamber in which the rarefaction zone is formed, a chamber for pre-mixing steam with heated water, connected by a pipeline through the valve to the inlet part of the active nozzles. The design of the pre-mixing chamber ensures the separation of the heated water supplied into it through the pipeline into the dispersed stream using jet nozzles and mixing it with the steam stream. Water is supplied to the preliminary mixing chamber due to the pressure difference between the pressure of the heated water in the active nozzle and the pressure of the heating steam. The resulting two-phase mixture is fed into the receiving chamber due to the difference in vapor pressure in the chamber and in the rarefaction zone. Subsequently, condensation of the two-phase steam-water mixture occurs on a stream of water, which leads to an increase in the temperature of the heated water.

An advantage of the known device is the possibility of expanding the ranges of flow rates of steam, water, pipe diameters, at which it can be used to heat water, since it allows you to switch from a large-scale two-phase flow structure to a small-scale one, thereby eliminating hydraulic shocks and vibration of pipeline systems. The prototype works well at vapor pressures lower than the water pressure in the supply water line.

The disadvantage of the prototype is the inability to supply water to the pre-mixing chamber at steam pressures, high water pressures taken from the zone at the entrance to the active nozzle, which narrows the scope of the prototype, and at close values of the water and steam pressures, the atomization of water in jet nozzles worsens and, therefore , the quality of the resulting two-phase mixture is deteriorating.

In some cases, the problem of ensuring the operability of the prototype at vapor pressures, high water pressures in the supply line can be solved, as is known, by narrowing the critical section of the active nozzle, however, this method leads to an increase in the hydraulic resistance of the heater.

As the operating experience showed, when the prototype was turned on, after the water was supplied to the active nozzle, the pre-mixing chamber of the pre-heater was filled with water, and after the steam was supplied, water was displaced from the pre-mixing chamber to the receiving chamber for some time (usually several minutes), the process of which water hammer is observed. The presence of this effect is unacceptable in industries associated with frequent shutdowns (starts) of the heater, for example, with an irregular schedule of water consumption.

Other disadvantages include the deterioration of the ejection characteristics of the active nozzle due to the selection of part of the flow rate of heated water in front of the active nozzle, as well as the complicated design of the preliminary mixing chamber.

To eliminate these disadvantages of the prototype, containing an active nozzle, a receiving chamber, a chamber for pre-mixing steam with liquid, a pipe for supplying liquid to a chamber for preliminary mixing, therein a pipe for supplying liquid to a chamber for preliminary mixing contains a fluid injection device, for example, a centrifugal pump, the suction pipe of which is connected with the entrance to the active nozzle, and the discharge pipe is connected to the pre-mixing chamber. The pump head is selected from the condition in order to raise the pressure of the liquid supplied to the preliminary mixing chamber to values exceeding the vapor pressure and ensuring effective splitting of the water jets at any vapor and water pressures.

To increase the ejection properties of the active nozzle of the heater, the suction pipe of the pump is connected to the outlet of the heater and selects the heated liquid, which is fed into the preliminary mixing chamber. In contrast to the prototype, to obtain a two-phase mixture, not heated but already heated liquid is used, which makes it possible to efficiently use the entire liquid flow passed through the active nozzle to create an ejection effect, as well as to provide milder modes of interaction of steam with the liquid in the preliminary mixing chamber.

The suction nozzle of the pump is connected by a pipeline to the preliminary mixing chamber, which ensures quick removal of the liquid filling it and its transformation into a cooled two-phase mixture at the initial moment of starting the heater into operation and, therefore, it is included in the operation practically without vibration and water hammer.

To simplify the design of the preliminary mixing chamber, tangential nozzles are made in the housing of the preliminary mixing chamber, which are communicated through the manifold surrounding it with the pump discharge line, and blades are installed on the inner surface of the housing.

Figure 1 shows the design of the proposed jet mixing liquid heater, figure 2 is a top view of the pre-mixing chamber, while the pipelines and fittings are not conventionally shown.

The heater includes an active nozzle 1, made in the form of a confuser and placed inside the receiving chamber 2, made in the form of a tee. An input line 8 is connected to the input of the active nozzle, through which the heated fluid is supplied to the heater. To the output of the receiving chamber is connected the output part of the heater 9 (line for draining the heated liquid). A pre-mixing chamber of 3 steam and liquid is attached to the upper nozzle of the receiving chamber by a flange connection. The housing of the preliminary mixing chamber is made of a cylindrical pipe in which tangential nozzles 21 are formed for passing fluid from the manifold 20, covering the housing of the chamber. Blades 19 are installed in the lower part of the preliminary mixing chamber on the inner surface. To supply steam to the preliminary mixing chamber, a nozzle 16 is used, in which holes are made within the part that is placed in the preliminary mixing chamber.

If the pressure of the heated fluid at the inlet to the nozzle is greater than the vapor pressure, the preliminary mixing chamber 3 can be communicated through line 4, with open shut-off valves 11 and 15, with an inlet water line 8.

If the pressure of the heated fluid is less than the vapor pressure, a connection is provided for the water supply pipe 5 through the valves 11 and 12 with the suction pipe of the pump 10, and the preliminary mixing chamber 3 (manifold 14) is communicated with the discharge pipe of the pump 10 through the open valves 13 and 15.

If the ejection properties of the nozzle are not sufficient for steam suction, it is possible to connect the outlet part 9 of the heater using a pipeline 7 and valves 18 and 12 with the suction pipe of the pump 10, and the discharge pipe of the pump is connected to the pre-mixing chamber.

To exclude hydraulic shocks when the heater is turned on, a connection is made to the suction pipe of the pump 10 with a pipe 6 and valves 17 and 12 with the lower part of the preliminary mixing chamber 3.

The operation of the heater is as follows.

Water under pressure through the supply line 8 enters the entrance to the active nozzle 1. In the active nozzle, the static pressure decreases due to acceleration of the water, and a high-pressure water jet with a pressure lower than the vapor pressure is formed at the outlet of the nozzle. Steam is supplied through the pipe 16 to the pre-mixing chamber 3. At the initial moment, after the liquid is supplied to the nozzle, the preliminary mixing chamber is filled with liquid. When steam is supplied, liquid is displaced from the preliminary mixing chamber under the influence of steam pressure and hydraulic shock occurs. To prevent such negative effects, the valves 17, 12, 13, 15 are opened and the pump 10 is turned on (the other valves are closed), as a result of which the liquid from the lower part of the premixing chamber is pumped out by the pump through pipeline 6, enters the manifold 20 and is introduced in the form of jets through tangential nozzle 21 into the pre-mixing chamber, where, mixing with steam jets, it turns into a two-phase mixture, with partial condensation of steam and thereby the pulsation and vibration characteristics of the flows in the chamber are reduced th mixing startup heater into operation. After the water is completely displaced from the preliminary mixing chamber, the pump is turned off and the valve 17 is closed, for example, by a signal from a medium continuity sensor or a liquid level sensor.

If the pressure of the heated fluid in the supply line 8 is greater than the vapor pressure in the pipe 16, part of the heated fluid under the influence of this pressure differential between the fluid and the steam through the pipe 4 (valves 11, 22, 15 are open) enters the pre-mixing chamber, where, mixed with steam , turns into a two-phase mixture, which in the receiving chamber 2 and the discharge line 9 condenses on a stream of liquid flowing from the active nozzle, thereby heating the liquid stream. The liquid stream supplied to the pre-mixing chamber is supplied through tangential nozzles 21 for better mixing, and the obtained two-phase stream having a peripheral component is inhibited on the straightening vanes 19.

If the pressure of the heated fluid is less than the vapor pressure, turn on the pump 10, and the heated fluid under pressure is pumped into the pre-mixing chamber by the pump (valves 11, 12, 13, 15 are open, the rest are closed). The supply of a heated liquid with a pressure exceeding the vapor pressure allows expanding the operational capabilities of the heater, and on the other hand, improving the quality of the two-phase mixture, ensuring the necessary fineness of the liquid spray, and thereby creating a developed heat exchange surface for steam and liquid flows.

To maintain the ejection characteristic of the active nozzle when the flow rate of the heated fluid passing through the active nozzle decreases as a result of the selection of part of the fluid in front of the nozzle, turn on the pump 10 and through pipe 7 (valves 18, 12, 13, 15 are open, the rest are closed), heated fluid is supplied under pressure into the pre-mixing chamber, where, mixing with steam, it forms a homogeneous two-phase mixture.

The features of the invention are:

- active nozzle;

- receiving chamber;

- a chamber of preliminary mixing of steam with liquid;

- a pipeline for supplying liquid to the premixing chamber;

- the pipeline for supplying liquid to the premixing chamber comprises a fluid injection device, for example a pump;

- the suction pipe of the fluid injection device is connected to the entrance to the active nozzle, and the discharge pipe to the pre-mixing chamber;

- the suction pipe of the fluid injection device is connected to the outlet of the heater, and the discharge to the pre-mixing chamber;

- the suction and discharge nozzles of the fluid injection device are connected to the pre-mixing chamber;

- tangential nozzles are made in the housing of the preliminary mixing chamber;

- tangential nozzles communicated with the discharge line of the pump through the manifold covering the housing;

- blades are installed on the inner surface of the housing of the premixing chamber.

Signs: "active nozzle, receiving chamber, pre-mixing chamber, liquid supply pipe to the preliminary mixing chamber" - common, the rest are distinctive.

Thus, the proposed mixing fluid heater has an inventive step, since the totality of the features of this technical solution determines a new property that gives the required technical effect: it provides continuous heating of the current fluid flow rate with steam introduced into the fluid flow when the pressure ratios of the heated water and heating steam vary over a wide range . In addition, the operational characteristics of the heater are improved when it is turned on, and the quality of the resulting two-phase mixture is improved without deterioration of ejection properties and without an increase in the hydraulic resistance of the heater.

Claims (4)

1. A jet mixing liquid preheater containing an active nozzle, a receiving chamber, a chamber for pre-mixing steam with a liquid, a pipe for supplying liquid to a chamber for pre-mixing, characterized in that the pipe for supplying liquid to a chamber for pre-mixing contains a fluid injection device, for example a pump, the suction nozzle of which is connected to the entrance to the active nozzle, and the discharge to the pre-mixing chamber. 2. The jet mixing liquid preheater according to claim 1, characterized in that the suction pipe of the pump is connected to the outlet of the preheater, and the discharge to the pre-mixing chamber. 3. The jet mixing liquid preheater according to claim 1 or 2, characterized in that the suction and discharge nozzles of the pump are connected to a chamber for pre-mixing steam with liquid. 4. The jet mixing liquid preheater according to claim 1 or 2, characterized in that tangential nozzles are made in the housing of the premixing chamber communicated through the manifold surrounding the housing with the pump discharge line, and blades are installed on the inner surface of the housing.

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