WO2001081832A1

WO2001081832A1 - Steam injector

Info

Publication number: WO2001081832A1
Application number: PCT/EP2001/004424
Authority: WO
Inventors: Rainer Fröb
Original assignee: Petrick & Wolf Energietechnik Gmbh
Priority date: 2000-04-19
Filing date: 2001-04-19
Publication date: 2001-11-01
Also published as: EP1277014A1; DE20007262U1; AU2001273951A1

Abstract

The invention relates to a device for injecting steam into flowing water in order to heat said water, comprising the following: (a) an essentially closed housing (404); (b) a mixing chamber (442) inside said housing (404), in which the steam is mixed with the water to be heated; (c) a water inlet (416) and a water outlet (420) in the housing (404), the water being guided from said water inlet (416) to said water outlet (420) via the mixing chamber (442); (d) a steam chamber (440) inside the housing; (e) a steam inlet (424) in the housing (404), the steam being guided from the steam inlet (424) into the steam chamber (440); (f) a dividing wall (430) between the steam chamber (440) and the mixing chamber (442), said dividing wall (430) being porous and having a number of pores (450) for the passage of the steam into the mixing chamber (442).

Description

Steam in ector

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, in which 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. Furthermore, the invention relates to such an injector as used in connection with the device for injecting steam into flowing water with the device for injecting steam into flowing water for the purpose of heating the water according to registered German Utility Model No. 297 19 007.5 is used. It is disclosed that in a device steam is injected into flowing water in a so-called injector and heats this water by the transfer of the heat of vaporization. In this device, the incoming steam is passed through small holes in a nozzle tube, in which a relatively high flow rate is achieved. This speed is used to shred the steam into small steam bubbles in a stainless steel gauze after exiting the nozzle holes. This size reduction is a prerequisite for the condensation of steam in water to be quiet. However, the manufacture of the nozzle tube with a large number of bores is complex and expensive.

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. These water strikes pose alongside the noise pollution due to the resulting pressure waves, there is also 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 introduce steam in the smallest particles in flowing water and thus to allow a completely silent condensation. It must be ensured that the quantity variability from 0 to 100% is always maintained and that the pressure drop between the steam line and the water to be heated does not exceed system-specific values.

According to the invention, a device for injecting steam into flowing water is proposed with an essentially 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 wall between the steam chamber and the mixing chamber, a large number of pores for passage in the partition wall of the steam are formed in the mixing chamber, the pore sizes being designed so that only the smallest steam particles penetrate the partition, with a suitable choice of the grain size be cooled and condensed immediately upon contact with the water flowing on the wall surface. Noises do not occur during this process.

It has been shown that such a structure is suitable for completely suppressing the disturbing water hammer and the associated noises and vibrations. If steam penetrates such small cross-sections as occur when a tube is made of ceramic or sintered metal, only the smallest vapor particles appear on the material surface, which are cooled and condensed immediately when they come into contact with the water flowing on the wall surface.

According to a further aspect of the present invention, it is provided that the steam ensures not only the heat transfer but also the static pressure maintenance in the water system, so that no local evaporation of the water can occur there. If the steam flows through the tube, there is a pressure loss that reduces the steam pressure that is available in the water space for maintaining pressure. However, pressure maintenance is necessary because the temperatures of the heated water can usually be above 100 ° C.

These temperatures depend on various property-specific criteria and are essentially identified as: Saturation temperature according to vapor pressure in the immediate condensation area on the tube surface;

maximum temperature in the design state according to the intended use and

Temperatures in the control range of the system.

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:

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

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

Reference is first made to FIG. 1. Superheated steam from a steam line 110 of a steam network of a district heating system is supplied 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. On A shut-off valve 104, a manometer 106 and a thermometer 108 are arranged in front of the injector 402 of the steam line 110.

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 thermostatic 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. Viewed in the direction of flow of the condensate, the condensate line 112 a shut-off valve 140, a motor-operated temperature controller 142, a flow differential pressure controller 144, a non-return valve 146 and a further shut-off valve 148 are arranged one behind the other. A manometer 150 is located between the check valve 146 and the shut-off valve 148.

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

With the reference number 158 is a central rule or Control module designates which the operation of the system depending on 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 separate 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 German Patent 44 32 464. Reference is made below 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 from FIG. 1, 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 (FIG. 1). 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 weld-on sleeve 428, which ends at the level of the parting plane between the upper and lower housing halves 406 and 408.

A tube 430 is connected tightly to the welding sleeve 428. The cylindrical tube 430, which is open on both sides, runs coaxially to the axis of the cylindrical cavity 414 of the housing 404 and extends to near the lower end of the cavity 414 and has an inside diameter di and an outside diameter d _a . The cylindrical tube 430, which is preferably made of ceramic or sintered metal, has a multiplicity of pores 450, which are shown in FIG. 2 as points of the dotted surface. For the tight connection of the tube 430, a threaded piece 452, seals 444, washers 434, a threaded rod 448, which has three welded-on brackets 446 at one end and a thread at the other end, and a hexagon nut 432 are required. The threaded piece 452 is screwed into the welded socket 428. The threaded rod 448 runs coaxially to the axis of the cylindrical cavity 414 of the housing 404, the three claws 446 touching the threaded piece 452, so that the threaded rod 448 is fixed. Between the threaded piece 452 and the cylindrical tube 432 there is a circular seal 444. Between the other open end of the tube 430 and a washer 434 there is also a circular seal ring 444. Between this washer 434 and another washer 434 there is a circular seal ring 444. The threaded rod 448 is threaded a suitable hexagon nut 432 is screwed on, so that tightening this hexagon nut 432 ensures that the steam space is connected to the mixing space 442 exclusively via the pores 450.

200 to 500 mm have proven to be an advantageous overall height for the tube 430.

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 vent dome 436 is provided with a steam vent 438.

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 surrounding the space 440 442, which is separated from the space 440 by the tube 430 (and its extension leading up to the steam inlet opening 424), the two spaces being connected to one another exclusively via the pores 450.

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 pores 450 into the mixing chamber 442, where it is used Purpose of heating is introduced into the water flowing therein.

Only the amount of steam that corresponds to the outflowing amount of water can flow into the injector. The outflow of water is regulated 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.

Two borderline cases are defined for the entire load range:

- water build-up in the entire tube; all pores are covered with water; steam cannot flow through the pores; no water flows out of the system; the amount of heat withdrawn is zero. - There is steam in the entire tube; all pores are released; the amount of steam equivalent to the outflowing amount of water flows; the amount of heat corresponds to the maximum output in the design state.

All other load points lie between the described limits.

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 discharged outside via the steam vent 438.

If no steam flows in the tube, because no condensate flows out on the water side, the water level in the tube rises to its upper edge. There is pressure equalization between the steam and water space and, all pores are covered with water. If the water begins to flow in the water space, the pressure drops slightly there. The resulting pressure difference corresponds to the geodetic height by which the water column (WS) in tube 430 is pressed down. Thus, pores 450 are released for the flow of steam.

Although the filter material has a constant porosity, the kvs value of the tube increases with the increase in steam throughput 430 because more pores are released for the steam flow with falling water column. The kvs value defines how much water flows through a constriction with a temperature of 20 ° C and 1 bar pressure loss. The maximum kvs value is reached when the water level in the tube reaches the lowest point. At this point lies the maximum flow rate of the steam, which is synonymous with the maximum power for heat transfer and the design status of the tube.

Ideally, the kvs value of the tube in [m3 / h] should be designed so that the pressure loss in [mWS] calculated with it corresponds to the overall height of the tube in [mm].

The kvs value can be determined with sufficient accuracy using the relationship

Here P means the specific permeability of water in m ³ / hcm ² , h the height of the tube in [mm], d _a the outer diameter of the tube in mm and di the inner diameter of the tube in mm.

With the kvs value, the pressure loss for steam can be calculated according to the conventional methods and, if necessary, a correction can be made if the pressure loss and tube height differ significantly. The standardization of the nominal widths of steel pipes is generally not the same as that of filter pipes. When designing the tube diameter, care should be taken that the inner diameter is equal to or greater than the nominal width of the steam pipe. Large wall thicknesses of the tube should be avoided because the pressure loss is increased, but requirements for material strength due to the low differential pressures between the interior and exterior should not be taken into account.

Claims

claims

1. Device for injecting steam into flowing water for the purpose of heating the water, with

a) a substantially closed housing (404),

b) a mixing space (442) within the housing (404), in which the steam with the to be heated

Water is mixed

c) each have a water inlet opening (416) and a water outlet opening (420) in the housing (404), the water from the

Water inlet opening (416) is led via the mixing space (442) to the water outlet opening (420),

d) a vapor 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 room (440), f) a partition (430) between the steam chamber (440) and the mixing chamber (442), the partition (430) being porous and having a plurality of pores (450) for the passage of the steam into the mixing chamber (442).

2. Device according to claim 1, characterized in that the partition (430) is designed as a tube made of ceramic or sintered metal.

3. Device according to claim 2, characterized in that the diameter of the tube (430) is equal to or greater than the nominal width of a steam line.

4. 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 region of the housing to the lower region.

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

6. The device according to claim 4 and 5, characterized in that the housing (404) one Elongated cavity (414} defines, at the upper end of which is the steam inlet opening (424}, to which, optionally with the interposition of a further pipe section (452), the downwardly extending tube (430) connects and that the water outlet opening (420) laterally is formed on an upper region of the housing (404).

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

8. Device according to one of the preceding claims, characterized in that the water outlet opening (420) is arranged above the pores (450).

9. Device according to one of the preceding claims, characterized in that the pores (450) have a diameter in the μm range.

10. The device according to one of claims 2 to 9, wherein the pressure drop of the steam flow flowing through the pores (450) of the tube (430} into the mixing space (442}) is equal to the hydrostatic pressure of a water column corresponding to the length of the tube (430}.

reference numeral

100 circulation line

104 shut-off valve 106 manometer

108 thermometers

110 steam pipe

112 condensate line

114 vent valve 118 pipe section

120 thermostat switches

122 sensors

124 pressure switches

126 safety valve 128 line section

130 manometers

132 drain valve

134 circulation pump

136 Non-return valve 138 Throttle valve

140 shut-off valve

142 temperature controller

144 flow differential pressure regulator

146 Non-return valve 148 shut-off valve

150 manometers

152 heat meter 154 sensors

156 sensors

158 regulating or control module

160 outside sensor 420 injector

404 housing

406 upper half of the case

480 under the housing half

410 flange 412 flange

414 cavity

416 water inlet opening

418 pipe socket

420 water outlet opening 422 pipe socket

424 steam inlet opening

426 pipe socket

428 welding socket

430 tube 432 hexagon nut

434 washer

436 vent dome

438 steam breather

440 steam room 442 mixing room

444 seal

446 claws

448 threaded rod

450 pores 452 threaded piece