EP1025399A1

EP1025399A1 - Device for injecting steam into flowing water in order to heat the water

Info

Publication number: EP1025399A1
Application number: EP98961036A
Authority: EP
Inventors: Rainer Fröb
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-10-24
Filing date: 1998-10-23
Publication date: 2000-08-09
Anticipated expiration: 2018-10-23
Also published as: EP1025399B1; WO1999022178A1; AU1661799A; DE59803776D1; DE29719007U1; ATE216054T1

Abstract

The invention relates to a device for injecting steam into flowing water in order to heat the water. The device comprises an essentially closed housing (404) and a mixing chamber (442) in which the steam is mixed with water which is to be heated. Said mixing chamber is located inside of said housing (404). One respective water inlet opening (416) and one water outlet opening (420) are arranged in the housing (404), whereby the water is fed from the water inlet opening (416) to the water outlet opening (420) via the mixing chamber (442). In addition, the inventive device has a steam chamber (440) located inside the housing and a steam inlet opening (424) which is also located inside said housing (404), whereby the steam is guided from the steam inlet valve (424) to the steam chamber (440). A separating wall (430) is situated between the steam chamber (440) and mixing chamber (442), whereby a plurality of nozzle bores which are arranged (432) in the separating wall (430) are provided for the accelerated entry of the steam into the mixing chamber (442). A fine-meshed structure (434) configured on the side of the separating wall (430) which faces the mixing chamber (442) at least in the area of the nozzle bores (432) is provided in order to reduce the exiting steam bubbles which are accelerated in the nozzle bores. The number of nozzle bore holes (432) and the diameters thereof are designed in such a way that a steam flow rate of 100 m/s is not exceeded in the area of the nozzle bores and/or the nozzle bores (432) are at least partially arranged at varying heights when the device is in an installed state.

Description

Device for injecting steam into flowing water for the purpose of

Heating the water

The invention relates to a device for injecting steam into flowing water for the purpose of heating the water. In particular, the invention relates to such an injector, as used in connection with a method according to German patent 44 32 464, which discloses a method for heating heating or process water by means of steam from the steam network of a long-distance line where the steam is injected into the water to be heated in the circuit, the amount of steam to be injected into the water being controlled by (outside) temperature-controlled removal of water or condensate into the condensate line of the steam network.

In known devices for introducing steam into water, serious problems arise in practice. The introduction of steam into water leads to so-called water hammer, because the steam bubbles are cooled by the surrounding water and a sudden volume contraction occurs due to the change in the physical state from steam to water. In addition to the noise pollution caused by the pressure waves that occur, these water hammer also represent a heavy material load and lead to premature material aging. These problems are intended to be avoided with the present invention.

The invention has for its object to provide an injector in which the injection of steam into the water is particularly quiet or noiseless.

Another object of the invention is to design the injector so that the steam can be introduced into the water in a variable amount from 0 to 100%, so that the injector can be used for heating in building technology depending on the outside temperature. The regulations of the heating system regulation and the safety regulations according to DIN 4751 should also be observed. The heat quantity to be transferred should only be regulated by means of a quantity-regulated outflow of water from the system and a subsequent flow of the equivalent amount of steam. With a transfer heat quantity of 0, the steam must be applied to the system as static pressure.

According to the invention, a device for injecting steam into flowing water is proposed with a substantially closed housing, a mixing space within the housing in which the steam is mixed with the water to be heated, in each case a water inlet opening and a water outlet opening in the housing, the water from the water inlet opening is led via the mixing chamber to the water outlet opening, a steam chamber within the housing, a steam inlet opening in the housing, the steam being conducted from the steam inlet opening into the steam chamber, a partition between the steam chamber and the mixing chamber, a plurality of nozzle bores in the partition wall for accelerating Passage of the steam are formed in the mixing chamber, and a fine-meshed structure on the wall of the partition facing the mixing chamber, at least in the region of the nozzle bores, for comminuting the Da acceleratingly emerging at the nozzle bores mpfblasen, the number of nozzle bores and their cross-section are designed so that in the area of the nozzle bores a flow rate of the steam of 100 m / s is not undercut.

It has been shown that such a structure is suitable in any case to reduce the disturbing water hammer and the associated noises and vibrations to such an extent that they are no longer perceived as disturbing. Due to the high outflow speed of the steam from the nozzle bores and the subsequent crushing of the steam bubbles in the fine bores and the subsequent crushing of the vapor bubbles in the fine-mesh structure, the vapor bubbles are crushed to such a degree that water collisions no longer occur when they collapse.

It has proven particularly advantageous here if the nozzle bores each have a diameter of at most 3 mm, better still at most 2 mm, and optimal results have been achieved with a nozzle diameter of about 1.5 mm.

Furthermore, it is advantageous to set the mesh size of the fine-mesh structure to at most 3 mm, preferably to about 2 mm. The material of the fine-mesh structure should preferably have a thickness of at most 1 mm, about 0.5 mm being particularly advantageous. Such a fine-mesh structure can be formed in particular by a fine-mesh stainless steel gauze, which is arranged in multiple layers above the nozzle bores. A total thickness of the fine-mesh structure of at least 5 mm, preferably at least 15 mm, has proven to be advantageous.

According to a further aspect of the present invention, it is provided that, when the device is installed, the nozzle bores are at least partially arranged at different heights. In this way it can be achieved that the introduction of steam can be variable in quantity. If no water or condensate flows out of the system, the steam space fills with water or condensate and rises to such an extent that the nozzle bores are completely in the water or condensate, so that steam can no longer be introduced into the mixing space is. In contrast, when the maximum amount of water or condensate is drained off, the amount of steam equivalent to the outflowing amount of steam flows into the injector and, in the area of the steam chamber, after the water has been displaced, it is completely filled with steam so that steam flows through all the nozzle bores and thus the maximum amount of steam is supplied. In the case of between the minimum and maximum performance lying load areas are released due to the fact that the nozzle holes are arranged at different heights, due to the different water level in the steam room, a different number of nozzle holes, whereby the amount of steam emitted and thus the amount of heat transferred can be regulated more or less continuously.

In a particularly advantageous development of the invention it is provided that the partition is at least partially designed as a nozzle tube which is connected to the steam inlet opening and extends downward into the cavity defined by the housing. In this case, the nozzle bores can in particular be formed spirally on the cylinder wall of the nozzle tube, which results in a practically stepless regulation of the amount of steam introduced.

Further advantageous features of the invention result from the following description, in which a preferred embodiment of the invention is described in more detail with reference to the drawing. The drawing shows:

Fig. 1 shows a system for heating water by means of steam from the steam network of a district heating system, in which an injector according to the invention is installed, and

Fig. 2 is a partially sectioned side view of a preferred injector according to the invention.

First, reference is made to FIG. 1. Superheated steam from a steam line 110 of a steam network of a district heating system is fed to a circuit line for heating water, which is designated as a whole by the reference number 100, and is completely vented via an injector 402 according to the invention. A shut-off valve 104, a manometer 106 and a thermometer 108 are arranged on the steam line 110 in front of the injector 402. Viewed in the direction of circulation of the water or condensate located in the circuit line 100 (the direction of flow runs clockwise in the illustration according to FIG. 1), after the injector 402, a vent valve 114 is arranged on the circuit line. The adjoining line section 118 of the circuit line can be referred to as the flow of the building heating and a thermostat switch 120, a sensor 122, a pressure switch 124 and a safety valve 126 are arranged one after the other.

After flowing through the heated heating water through the heat consumers (radiators), which are not shown, the heating water returns via the line section 128 to be referred to as the return line, a manometer 130 and then an emptying valve 132 being arranged on this line section. The cooled heating water is then returned to the injector 402 via a circulation pump 134, a non-return valve 136 and a throttle valve 138.

The condensate line 112 branches off between the check valve 136 and the throttle valve 138, via which the condensate is returned to the district heating network. Seen in the direction of flow of the condensate, a shut-off valve 140, a motor-operated temperature regulator 142, a flow differential pressure regulator 144, a non-return valve 146 and a further shut-off valve 148 are arranged in series in the condensate line 112. A manometer 150 is located between the check valve 146 and the shut-off valve 148.

A heat meter 152 is arranged between the line section 128 and the circulating pump 134 and works in a known manner with a sensor 154 or 156 attached to the line section 118 (flow) and 128 (return).

The reference number 158 denotes a central regulating or control module which controls the operation of the system as a function of the outside temperature, cf. Outside sensor 160, controls. While in the case of the exemplary embodiment described above, the steam is fed directly into the heating water, two alternatively hydraulically separated circuits can also be provided, namely a condensate circuit and a heating circuit, both circuits being thermally connected to one another by an intermediate heat exchanger.

For further details regarding the structure and operation of the system, reference is expressly made to the German patent 44 32 464.

In the following, reference is made to FIG. 2, which shows a preferred embodiment of the injector according to the invention in detail.

It should be said that the injector 402 according to the invention is installed in the heating system in the position shown in FIG. 2, that is to say in the upright position.

The injector 402 comprises an essentially cylindrical housing 404 with an upper housing half 406 and a lower housing half 408, both housing halves being flanged together by means of flanges 410, 412. The housing 404 has a substantially cylindrical cavity 414 and, with the exception of the openings described below, is closed on all sides. At the lower end of the housing 404, a water inlet opening 416 is defined, which is connected via the pipe socket 418 to the line section of the circuit line 100, which leads to the throttle valve 138. Provided laterally in the upper housing half 406 of the housing 404 is a water outlet opening 420 which is formed radially to the central axis of the housing and is connected via a pipe socket 422 to the line section of the circuit line 100 leading to the vent valve 114. The opening 420 is located in the upper region of the housing 404, but is spaced from the upper end of the cavity 414 for the reasons described below. A steam inlet opening 424 is formed at the upper end of the housing 404 and is connected to the steam line 110 via an angled pipe socket 426. A steam pipe section extends downward from the steam inlet opening 424 and ends in a welding sleeve 428, which ends at the level of the division between the upper and lower housing halves 406 and 408.

A nozzle tube 430 is interchangeably screwed into the weld-on sleeve 428 via a thread (not shown). The cylindrical nozzle tube 430 is coaxial with the axis of the cylindrical cavity 414 of the housing 404, is closed at its lower end and extends to near the lower end of the cavity 414. The nozzle tube 430 has a multiplicity of small nozzle bores 432 which are spirally in one or several spirals are formed in the cylindrical outer surface of the nozzle tube and are evenly distributed.

The nozzle tube 430 is wrapped with a fine-meshed stainless steel gauze 434, this stainless steel gauze being arranged one above the other in a plurality of layers and covering the entire area of the nozzle bores 432.

At the upper end of the housing 404, a vent dome 436 is formed, which is defined by the cavity above the water outlet opening 420. The dome bottom of the venting dome 436 is provided with an automatic steam vent 438.

In the case of the preferred embodiment, the diameter of the nozzle bores is 1.5 mm. The stainless steel gauze consists of wire with a diameter of 0.5 mm and a mesh size of 2 mm. The winding thickness of the stainless steel gauze is 15 mm.

When dimensioning the steam line, a maximum flow rate of 25 m / s must be maintained for the selected nominal size. The Number of nozzle bores and thus the injection cross-section are chosen so that a flow rate of preferably 130 m / s is not undercut at full steam throughput. The flow rate of the water to be heated is chosen so large that the temperature at the water outlet clearly falls below the saturation temperature.

It follows from the construction of the injector according to the invention described above that it comprises a central cylindrical space 440, via which the steam enters the housing of the injector, and an annular space 442, which surrounds the space 440 and which passes from the space 440 through the nozzle tube 430 (and its extension leading up to the steam inlet opening 424) is separated, the two spaces being connected to one another exclusively via the nozzle bores 432.

In operation, the water circulates with a constant or variable flow from the water inlet opening 416 via the mixing chamber 442 to the water outlet opening 420. The steam enters the steam chamber 440 from the steam inlet opening 424 and passes through the nozzle bores 432 into the mixing chamber 442, where it is used Purpose of heating is introduced into the water flowing therein.

In order to inject the steam into the water silently, the steam bubbles must be very small. The first phase of shredding is done by the steam passing through the small nozzle holes. In the second phase, the steam accelerated in the nozzle bores enters the gauze winding 434. Upon impact with the fine-meshed structure, the vapor bubbles are divided several times and thus reach a size that may result in a boiling noise during the subsequent condensation. The condensation completes the heat transfer from steam to the water to be heated. Only the amount of steam that corresponds to the outflowing amount of water can flow into the injector. The outflow of water is controlled by the temperature controller 142 in the condensate line 112, so that no control valve for the amount of steam may be used on the steam side.

In order to ensure the described vapor bubble comminution in the entire load range between 0 and 100%, the flow velocity in the nozzle bores must not fall below a minimum velocity, which was set at 130 m / s in the case of the present exemplary embodiment, even with a lower vapor throughput. With the reduction in the amount of steam, the injection cross section must therefore also be reduced in order to keep the flow rate constant. The injection cross-section is reduced by changing the water level in the nozzle pipe due to the regulated water flow and thus blocking the nozzle bores covered with water for the passage of steam.

Two limit cases are defined for the entire load range:

- Water build-up in the entire nozzle tube, all holes are covered with water, so no steam can flow through the nozzle holes, no water flows out of the system, the amount of heat removed is zero.

- There is steam in the entire nozzle tube, all nozzle bores are released, the equivalent of the outflowing amount of water flows

Amount of steam, the amount of heat corresponds to the maximum output in the design state.

All other load points lie between the limits described. In the event that air mixed with the steam enters the injector, the two gases can only be separated after the steam has condensed. The air bubbles entering the injector can collect under the vent dome 436 and are automatically discharged to the outside via the steam vent 438.

Reference list

Circuit line 160 external sensor shut-off valve 402 injector manometer 404 housing thermometer 406 upper housing half steam line 408 lower housing half condensate line 410 flange vent valve 412 flange line section 414 cavity thermostatic switch 416 water inlet opening sensor 418 pipe connection pressure switch 420 water outlet opening safety valve 422 pipe connection line section 424 steam valve outlet 428 connection pipe outlet pump manometer 42 Non-return flap 432 Nozzle bores Throttle valve 434 Stainless steel gauze shut-off valve 436 Vent dome temperature controller 438 Steam breather Flow differential pressure controller 440 Steam room Non-return flap 442 Mixing room shut-off valve Manometer Heat meter Meter Sensor Sensor control and control module

Claims

Expectations

Apparatus for injecting steam into flowing water for the purpose of heating the water, comprising a) a substantially closed housing (404), b) a mixing space (442) within the housing (404), in which the steam contains the water to be heated is mixed, c) in each case a water inlet opening (416) and a water outlet opening (420) in the housing (404), the water coming from the water inlet opening

(416) via the mixing space (442) to the water outlet opening (420), d) a steam space (440) within the housing, e) a steam inlet opening (424) in the housing (404), the steam from the steam inlet opening (424 ) is passed into the steam space (440), f) a partition (430) between the steam space (440) and the mixing space (442), a large number of nozzle bores (432) in the partition (430) for accelerated passage of the steam into the mixing space (442) are formed, and g) a fine - mesh structure (434) on the wall of the partition (430) facing the mixing chamber (442) at least in the area of the nozzle bores (432), for crushing the vapor bubbles emerging at the nozzle bores , where h1) the number of nozzle bores (432) and their cross-section are designed such that a flow velocity of the steam of 100 m / s is not undercut in the area of the nozzle bores, and / or h2) in the installed state of the device The nozzle bores (432) are at least partially arranged at different heights.

2. Device according to claim 1, characterized in that the nozzle bores (432) each have a diameter of at most 3 mm, preferably at most 2 mm, in particular about 1, 5 ± OJ mm.

3. Device according to claim 1 or 2, characterized in that the mesh size of the fine-mesh structure (434) is at most 3 mm, preferably about 2 mm.

4. Device according to one of the preceding claims, characterized in that the material of the fine-mesh structure (434) has a thickness of at most 1 mm, preferably of about 0.5 mm.

5. Device according to one of the preceding claims, characterized in that the fine-mesh structure (434) is a stainless steel gauze.

6. Device according to one of the preceding claims, characterized in that the fine-mesh structure (434) has a (measured perpendicular to the plane of the partition) thickness of at least 5 mm, preferably of at least 15 mm.

7. Device according to one of the preceding claims, characterized in that the water inlet opening (416) on a lower region of the housing (404) and the water outlet opening (420) and the steam inlet opening (424) are formed on an upper region of the housing (404) and the partition (430) extends downward from an upper portion of the housing to the lower portion.

8. Device according to one of the preceding claims, characterized in that the steam inlet opening (424) is connected to a nozzle tube (430) which defines the partition.

9. Apparatus according to claim 7 and 8, characterized in that the housing (404) defines an elongated cavity (414), at the upper end of which is the steam inlet opening (424), to which, optionally with the interposition of a further piece of pipe, which downwardly extending nozzle tube (430) connects and that the water outlet opening (420) is formed laterally on an upper region of the housing (404).

10. Device according to one of the preceding claims, characterized in that a venting device (436, 438) is formed above the water outlet opening.

1 1. Device according to one of the preceding claims, characterized in that the nozzle bores (432) are formed spirally on the cylinder wall of a nozzle tube (430).

12. Device according to one of the preceding claims, characterized in that the water outlet opening (420) above the nozzle bores (432) is arranged.