Steam generator, and system for steam cleaning workpieces

Abstract

A device for cleaning workpieces with a steam jet is proposed, with a special steam generator in which the steam is generated in a hollow cylindrical core, whose outer side is heated and onto whose inner side the water to be vaporized is sprayed by means of a nozzle. The steam generator has a supplementary heating device with a heatable body having a cavity through which steam generated upstream can flow for post-heating it, in order to generate dry steam for dry steam cleaning. An automated cleaning system with this steam generator is also proposed. The device can be adapted flexibly to the requirements of automated synchronized production and requires, in particular, less energy and floor space. The invention can be used, among other things, in industrial cleaning in manufacturing systems engineering, in particular in the production of automotive parts.

Claims

1. A steam generator (1) for generating dry steam for an automated industrial cleaning system (30) for cleaning workpieces by means of a steam jet, comprising a steam generator container with a water inlet (5) and a steam outlet (9); a heatable core (2) of thermally conductive material arranged in the steam generator container and having an inner primary cavity and an inner surface (2A); a primary heating device (8) for heating the core (2); a spray nozzle (6) connected to the water inlet (5) and arranged to spray water in a dosed manner onto the inner surface (2A) of the core (2); and an additional supplementary heating device (10) provided in the steam generator container upstream of the steam outlet (9) and at least partially inside the core (2); wherein the supplementary heating device (10) comprises a heatable body (10A) having a secondary cavity (11) through which steam (13) generated upstream in the primary cavity of the core (2) can flow for post-heating it to dry steam (14) and which is connected at an inlet side via a passage opening (12) to the primary cavity of the core (2) and at an outlet side to the steam outlet (9).

2. The steam generator (1) according to claim 1, wherein the passage opening (12) comprises or forms a cross-sectional constriction which causes a pressure difference with a lower pressure in the secondary cavity (11) of the supplementary heating device (10) than in the primary cavity inside the core (2).

3. The steam generator (1) according to claim 1, wherein the passage opening (12) is provided radially or axially with respect to a longitudinal axis of the core (2).

4. The steam generator (1) according to claim 1, wherein the primary heating device comprises a controllable electrical heating element (8) and that the supplementary heating device (10) comprises at least one separately controllable electrical heating element (10B).

5. The steam generator (1) according to claim 1, wherein the supplementary heating device (10) is accommodated at least to a major proportion of its overall length or completely with the heatable body (10A) axially inside the core (2).

6. The steam generator (1) according to claim 1, wherein the spray nozzle (6) is arranged axially to the hollow cylindrical core (2) and/or is directed towards the cylindrical inner surface (2A) of the core (2), wherein the spray nozzle (6) being designed with hollow cone characteristics.

7. The steam generator (1) according to claim 1, wherein the water inlet (5) is arranged at one end face (3) and the steam outlet (9) is arranged at the other end face (4), wherein the supplementary heating device (10) is mounted on the end face (4) opposite the water inlet (5).

8. The steam generator (1) according to claim 1, wherein the core (2) is in the shape of a hollow cylinder with a cylindrical inner surface (2A) and/or the steam generator container is configured in substantially cylindrical shape with an inner core (2), which is closed in a pressure-tight manner at the end faces (3, 4), wherein a thermal insulation (15) is provided between the inner core and an outer jacket (18) of the steam generator container.

9. The steam generator (1) according to claim 8 wherein the steam generator container has a thermally reflective inner jacket (16) between the thermal insulation (15) and the core (2).

10. The steam generator according to claim 1, wherein the core (2) is designed in the form of a jacket or hollow cylinder made in one piece of stainless steel with a cylindrical inner surface (2A) and end facing connecting flanges, for pressure-tight sealing at the end faces (3; 4); and/or exactly one passage opening (12) or more passage openings (12) are provided in the heatable body (10A); and/or the water inlet (5) and the steam outlet (9) are coaxially provided on opposite end faces (3, 4) of the core of the steam generator container; and/or the spray nozzle (6) has a spray characteristic coaxially aligned with the axis of the core (2); and/or the steam generator container is oriented vertically with its cylinder axis in an operating position; and/or the additional supplementary heating device (10) is arranged on the axis of the cylindrical steam generator container at the steam outlet (9).

11. An industrial cleaning system (30) for cleaning workpieces by means of a steam jet, comprising: a cleaning chamber (31) with at least one steam nozzle (32) in the cleaning chamber, a handling device (48) capable of positioning a workpiece and the at least one steam nozzle relative to one another; and at least one steam generator (1), which supplies the steam nozzle with steam, the at least one steam generator (1) comprising: a steam generator container with a water inlet (5) and a steam outlet (9); a heatable core (2) of thermally conductive material arranged in the steam generator container and having an inner primary cavity and an inner surface (2A); a primary heating device (8) for heating the core (2); a spray nozzle (6) connected to the water inlet (5) and arranged to spray water onto the inner surface (2A) of the core (2); and an additional supplementary heating device (10) provided in the steam generator container upstream of the steam outlet (9) and at least partially inside the core (2), the supplementary heating device (10) comprising a heatable body (10A) having a secondary cavity (11) through which steam (13) generated upstream in the primary cavity of the core (2) can flow for being post-heated (14) and which is connected at an inlet side via a passage opening (12) to the primary cavity of the core (2) and at an outlet side to the steam outlet (9).

12. The cleaning system according to claim 11, wherein a dosing valve is provided between the steam outlet (9) of the steam generator (1) and the at least one steam nozzle in order to discharge steam in dosed and/or pulsed form; and/or upstream of the water inlet a pump (36) is arranged, which applies a feed water pressure suitable for injection to the spray nozzle (6).

13. The cleaning system according to claim 11, wherein the system comprises a control unit (50) which controls at least the relative movement between the workpiece (49) and the steam nozzle (32) and the operation of the at least one steam generator (1) in a coordinated manner, and a controllable outlet shut-off valve (26) is provided downstream of the steam outlet, wherein the control unit (50) controls the outlet shut-off valve (26).

14. The cleaning system according to claim 11, wherein the cleaning chamber (31) is designed as a closable cleaning container and the handling device (48) is a holding and conveying device which is capable of holding the workpiece (49), conveying it into and out of the cleaning container (31), and moving the workpiece (49) relative to the steam nozzle (32); and/or an industrial robot with at least four degrees of freedom is provided in the cleaning chamber (31), on which the steam nozzle (32) is arranged in order to move it relative to the workpiece.

15. A device according to claim 1, wherein a plurality of identical steam generators (1) are provided in a battery arrangement (20), which have a common water distributor (22) for feeding the individual water inlets (5) and a common steam distributor (25), supplied by the individual steam outlets (9), for discharging steam.

16. An industrial cleaning system (30) for cleaning machined components for a drive train of a motor vehicle, comprising the steam generator of claim 1.

17. The steam generator (1) according to claim 6, wherein the spray nozzle (6) is designed with a hollow cone nozzle characteristic and/or with a nozzle geometry which ensures a volume flow of <0.2 l/min at a nozzle inlet pressure of ≤10 bar.

18. The steam generator (1) according to claim 1, wherein the core has a hollow cylindrical configuration and wherein the supplementary heating device (10) is mounted coaxially in the core (2) and completely accommodated therein.

19. The cleaning system according to claim 13, wherein a controllable supply shut-off valve (23) is provided upstream of the water inlet (5) and the control unit (50) controls the supply shut-off valve (23) and the outlet shut-off valve (26) in a coordinated manner.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

(2) In the drawings:

(3) FIG. 1A is a longitudinal sectional view of an individual steam generator unit of the device according to an embodiment of the invention;

(4) FIG. 1B is an exploded view of the steam generator unit of FIG. 1A;

(5) FIG. 1C is a sectional view of another steam generator unit according to an embodiment of the invention;

(6) FIG. 2 is a perspective view of a steam generator battery with two units according to FIG. 1A and associated line and valve technology;

(7) FIG. 3 is a simplified flow diagram of an industrial cleaning system with a steam generator battery according to FIG. 2; and

(8) FIG. 4 is a simplified raw material line and instrument flow schematic of a steam generator battery with steam generator units according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(9) In FIG. 1A, a steam generator 1 is shown in a horizontal arrangement in a longitudinal section, but in practice, a vertical arrangement of the hollow cylindrical axis would be preferred. The steam generator 1 comprises, in its interior, a hollow cylindrical jacket that consists essentially of a special core 2, a first end face 3, and a second end face 4 opposite the first end face. The end faces 3, 4 are designed like a flange and seal the core 2 pressure-tight.

(10) In the axis of the first end face 3, a water inlet 5 is mounted, which feeds a hollow cone spray nozzle 6, wherein here the terms injection nozzle and spray nozzle refer to identical components. Water flowing through the water inlet 5 into the hollow cone spray nozzle 6 is sprayed in a dosed manner to form a hollow cone-shaped spray jet 7 that is sprayed onto the inner surface of the core 2. The feed water pressure is preferably in the range from approx. 2 to 9 bar (atm). The nozzle geometry, in particular, jet angle and nozzle cross section of the spray nozzle 6 are selected so that low water consumption can be achieved, e.g., <0.15 l/min.

(11) Because the core 2 is heated by one or more electrical heating conductors 8, water from the spray jet 7 vaporizes when it impacts the core or while it flows downward on the inner surface of the core 2 and is converted into saturated steam, whose flow is indicated by the arrows 13. Several heating conductors 8, each with approx. 1.2-3.6 kW power can be provided as the primary heating device, e.g., in double spirals on the outside of the core 2. Preferably, receptacle grooves for the heating conductor 8 can be provided on the outside of the core 2 (FIG. 1B).

(12) In the axis of the core 2, an additional heating device 10 is arranged, e.g., a heated hollow cylinder with approx. 4 to 8 heating elements 10B distributed coaxially around the axis, each, e.g., with 500W electrical power. The power of the heating element 10B of the additional heating device 10 is controlled separately from the primary heating device with the heating conductors 8 and is supplied with energy here by not shown electrical connections. The supplementary heating device 10 makes it possible to selectively generate also dry steam (superheated steam). The heating device 10 has a body 10A with an axial hole 11, which is connected to the steam outlet 9 on the second end face 4. Thus, the saturated steam 13 generated on the heated core 2 can flow through one or more passage openings 12 into the hole 11 in the body 10A of the additional heating device 10 and can be led from there to the steam outlet 9, where the steam is led via a valve to one or more steam nozzles (FIG. 3) in a cleaning chamber. If energy is fed to the heating device 10, then the saturated steam 13 is further heated in the sense of post-heating and leaves the steam outlet 9 as dry steam 14. The heating elements 10B of the heating device 10 can be optionally controlled individually, in order to be able to precisely set the steam parameters.

(13) The heating elements 10B can be mounted distributed about the hole 11 in the body 10A, e.g., each in a corresponding axial hole open toward the end face 4 and are connected in a heat conductive manner to the body 10A, e.g., in that the heating elements 10B are mounted in a force-fit connection in the body 10A.

(14) FIG. 1B illustrates the preferred compact, axially nested construction of the steam generator 1 according to FIG. 1A, in the form of a steam cartridge. FIG. 1B shows structurally identical components with the same reference symbols as FIG. 1A.

(15) The jacket-like core 2 is a specially prepared, one-piece molded part made from stainless steel with a cylindrical inner surface (FIG. 1A) and sealing flanges on the end face for the pressure-tight connection to flange elements of the end faces 3, 4. On the outside, spiral, wrap-around receptacle grooves are formed for, e.g., strip-like heating conductors 8. The core 2 is constructed here, as FIGS. 1A-1B show, similar to a hollow cylinder with a cylindrical inner surface 2A and should have the smallest possible mass.

(16) Between the thermally reflective inner jacket 16 and the spacer 19 on which the insulating material 15 is mounted, additional insulation can be optionally provided. The end faces 3, 4 have a flange-like configuration made from individual parts that are sealed on the end-face flanges of the core 2, thermally insulate and at the same time connect the inner jacket 16 and the outer jacket 18 coaxially and rigidly to the core 2. The supplementary heating device 10 is held coaxially inside the core 2 (FIG. 1A) and leaves a cylindrical, peripheral free space, in order to obtain a maximum vaporization surface area on the inner surface of the core 2. The structural length and diameter of the core 2 are matched to the geometry, in particular, the spray cone angle, of the spray nozzle 6. The cartridge-like construction shown in FIGS. 1A-1B simplifies, among other things, maintenance work, e.g., replacing the spray nozzle 6.

(17) The silvering on the inner jacket 16 reduces losses due to thermal radiation. Between this inner jacket 16 and the outer surface of the core 2, a jacket-shaped, peripheral air gap 17 is provided as additional insulation. Instead of the air gap 17, with corresponding added expense, a vacuum or low pressure can also be provided here according to the principle of a Dewar flask; this, however, makes the construction and maintenance more difficult.

(18) A preferred refinement of a steam generator 1′ according to the principle from FIGS. 1A-1B is shown in FIG. 1C in cross section. The steam generator 1′ differs primarily in that a passage opening 12, here exactly one passage opening, is provided coaxially in the body 10A of the reheater 10, namely on the side of the spray nozzle 6. The passage opening 12 leads from the primary cavity 2B into the secondary cavity 11, e.g., a hole in the body 10A. This passage opening 12 also causes a pressure difference with lower pressure in the secondary cavity 11, e.g. 3.5 bar, relative to the operating pressure in the primary cavity 2B of the core 2, e.g., approx. 4 bar. The cross-sectional constriction of the passage opening 12 prevents a discharge of non-vaporized water mist. By decompressing the steam or reducing the pressure in the secondary cavity 11, dry steam 14 can also be prepared while supplying less energy. For generating a predetermined pressure reduction, e.g., a nozzle 12A or another component like a throttle, aperture, or the like could be provided on or as the axial passage opening 12, e.g., in an axial threaded hole on an end face on the body 10A. Furthermore, FIG. 1C shows one of two retaining rings 16A made from material with low heat conductivity, with which the reflective inner jacket 16 is held on the end face in point contact at a distance relative to the inner surface 2A of the core 2. Each retaining ring can be screwed onto the core 2, e.g., on the end face. In addition to the insulation 15 on the inside on the outer jacket 18, according to FIG. 1C for thermal insulation, external insulation 15A is also provided, with which the outer jacket 18 is surrounded.

(19) Other details from FIG. 1C match FIGS. 1A-1B, e.g., the hollow cylindrical inner surface 2A of the core 2 and the round cylindrical shape of the inner jacket 16 and outer jacket 18. Furthermore, e.g., FIG. 1C also shows the peripheral, symmetric distribution of the heating element 10B, here, e.g., six pieces, in the body 10A and the shape of the body 10A as a rotational body in cross section, with outer recesses for increasing the heat transfer effective to the outside to the primary cavity 2B and reducing the mass of the body 10A. The outside of the body 10A can have a conical profile toward the nozzle 6 and is, in any case, at a distance to the inner surface 2A of the core 2. Through the complete, here coaxial, holding of the reheater 10 in the inner cavity 2B of the core 2, the energy requirements are further reduced. In addition, the primary cavity 2B, thanks to the pressure reduction through the passage opening 12, can form a certain kind of steam buffer, so that dry steam 14 is generated as needed if a drop occurs at the steam outlet 9. The replaceable heating elements 10B can be inserted or pressed in as C-shaped heating elements that “unfold” in cross section into axial holes from the end face 4, in order to form a rigid and planar contact on the body 10A, as shown schematically in FIG. 1C.

(20) FIG. 2 shows a steam generator battery 20 with two or four steam cartridges or steam generators 1, e.g., each with approx. 4-6 kW heating power, in the construction according to FIGS. 1A-1B. The modular steam generator battery 20 according to FIG. 2 can generate approx. 18-20 kg/h wet steam at nominal approx. 2-4 bar operating pressure and can be optionally provided multiple times in parallel arrangement. For pulsed operation, steam can be discharged at a maximum pressure of >10 bar. On the input side, the water feeds of the steam generator units 1 are connected via a common feed water distributor 22 to a pneumatically/electrically controllable dosing/shut-off valve 23 for the dosed application with feed water. The feed water distributor 22 guarantees a uniform feed pressure to the spray nozzles 6 (FIG. 1) of the two steam generators 1. Pressure relief 24 on the feed water distributor 22 prevents air from entering into the spray nozzles 6 (FIG. 1). On the output side, each steam outlet 9 (FIG. 9) is connected directly to a steam distributor 25. The steam distributor 25 has, on one side, a controllable shut-off valve 26 for the controlled steam discharge to steam nozzles of a cleaning chamber of the cleaning device or system (see FIG. 3). A pressure-limiting valve or safety valve 27 on the steam distributor 25 protects the steam cartridges 1 from excess pressure. On the other side, the steam distributor 25 is connected to a valve 28 for the quick steam outlet (pressure outlet), e.g., for a controlled emergency shutdown (emergency off).

(21) FIG. 3 shows an overview diagram of the cleaning system 30 with at least one, preferably 2 to 4, steam generator batteries 20 in the construction according to FIG. 2. In the cleaning or treatment chamber 31, there are multiple steam nozzles 32, here, e.g., on two opposite rotor-like support arms, which perform a rotational motion for the planar cleaning of the workpiece 49 during the steam cleaning. The steam nozzles 32 can have a known construction and are supplied by a steam supply line 33, which is connected at the output of the steam generator battery/batteries 20, more specifically to the steam distributor 25 (FIG. 2).

(22) FIG. 3 further shows a return circuit of the cleaning system 30, with which cleaning fluid is recovered from the treatment chamber 31. The vapors occurring due to the low pressure are suctioned from the treatment chamber 31 via a first filter unit 41 by a vacuum pump 40 and then fed to a downstream second filter and separator stage 42, which has an oil separator 43. The outlet of the filter unit 41 opens into the oil separator 43. On the output side, the vacuum pump 40 is connected to a condensation unit 44, whose return also opens in the oil separator 43. From a clean tank 45 in the second filter and separator stage 42, the steam generator battery 20 with the individual steam generators 1 is fed via a water pump 36 in a supply line 37 via the feed water distributor/s 22. The water pump 36 generates the desired feed water pressure for the individual steam generators 1, e.g., approx. 8 bar (atm). The steam generators 1 deliver, depending on the nozzle geometry, heating output, and operating mode, a desired steam pressure, e.g., in the range from 2 to 6 bar (atm) at the steam nozzles 32.

(23) The output pressure of the steam generator 1 or the steam distributor 25 (FIG. 2) and optional additional suctioning effect of the vacuum pump 40 improves the spraying of steam at high dynamic jet pressure and thus also the cleaning effect. Operating the cleaning chamber 31 at low pressure is purely optional. In the closed circuit according to FIG. 3, the condensed discharge water (optionally with vapor) condensed out of the cleaning chamber 31, so that cleaning fluid is recovered. In addition, residual heat of the recovered cleaning fluid can be utilized for the purpose of additional energy savings. Fresh water is fed only as needed due to the losses, among other things, in the second filter and separator stage 42. The recovery is especially advantageous, when distilled or demineralized water is used for generating the steam, in order to guarantee a long operating period of the steam generator 1, especially of the hollow cone spray nozzles 6.

(24) FIG. 3 shows, purely as an example and schematically, an automatic handling device 48 for the workpiece 49, which can be moved automatically into and back out of the treatment chamber 31 on two axes H, V. The handling device 48 moves the workpiece 49 relative to the steam nozzles 32 into the treatment chamber 31. The handling device 48 also has a pressure-resistant closure that closes the opening of the treatment chamber 31 in the operating position in a pressure-tight manner.

(25) In an alternative embodiment (not shown here), one or more steam nozzles 32 can be arranged in the treatment chamber 31 on an automatic handling device and are herewith selectively positioned and/or moved relative to the workpiece. For this purpose, e.g., a 6-axis industrial articulated-arm robot can be used (see FIG. 1 in WO 2011/124 868 A1).

(26) FIG. 3 shows a fully automatic system control unit 50, which controls the operation of the steam generator battery/batteries 20 in a coordinated way with the operation of the cleaning chamber 31, e.g., synchronized operation of the automatic handling device 48. The system control unit 50 can also control the feed water pump 36 and/or regulate it in an energy-optimized way, e.g., by regulating the rotational speed. The control and measuring lines of the system control unit 50 are constructed using known technology and indicated here schematically with dashed lines. The system control unit 50 can also advantageously control actuators and sensors of the return circuit, e.g., the control valves, vacuum pump 41, and condensation unit 44 with respect to the operation of the cleaning chamber 31 and the steam generator 20 in a coordinated way and/or as needed, in order to realize additional energy savings.

(27) Each steam generator battery 20 can be controlled individually here as needed, in agreement with the synchronized operation of the operating chamber 31 and/or the requirements of the cleaning process of the steam nozzles 32 by the system control unit 50. By means of separate dosing valves (not shown), each steam generator 1 in a steam generator battery 20 can be optionally controlled individually, in order to be able to adjust the steam output even more precisely.

(28) One especially simple solution for the synchronized output of steam, especially dry steam 14, from the steam generator battery/batteries 20 can be realized by a suitable control valve (not shown) in the steam supply line 33, which is controlled by the system control unit 50 as needed. The control valve is preferably arranged close to the steam nozzles 32 with short residual line. For optimizing energy, the system control unit 50 controls the water supply via the feed valve 23 and also the heat output of each steam generator 1 via the primary and secondary heating devices 8, 10A as needed in agreement with the automated cleaning.

(29) FIG. 4 shows a steam generator battery 20 with measuring elements and control elements preferably provided for the process control or regulation by the system control unit 50 and, e.g., four structurally identical steam generators 1A, 1B, 1C, 1D according to FIGS. 1A-B and FIG. 1C. Parts with identical functions according to FIGS. 1-3 have the same reference symbols in FIG. 4.

(30) In each steam generator 1A . . . 1D there is a primary temperature sensor 61 (not in FIGS. 1A-1C) on the core 2 for controlling or regulating the power of the primary heating device 8 as a control element, e.g., to a target temperature up to 600° C. Accordingly, for the independent control or regulation of the secondary heating device 10B of the reheater 10 as a separate control element, a secondary temperature sensor 62 (not in FIGS. 1A-1C) could also be provided on the body 10A. The temperature sensors 61, 62 are connected as measuring elements to the system control unit 50. The system control unit 50 is also connected to a pressure sensor 63 on the feed water distributor 22. By means of suitable control elements, e.g., the control unit of the feed pump (see FIG. 3 at input “PSP”) and/or an overflow valve 64, the feed pressure can be set or regulated, either by the system control unit or optionally as a fixed preset condition, to a feed pressure, e.g., up to 8 bar. If no steam is required, the system control unit 50 switches off the water feed by means of the controllable feed valve 23.

(31) An additional pressure sensor 65 is provided as a measuring element on the steam distributor 25 and measures the steam pressure discharged at the steam outlet 9, among other things, for the controlled pressure relief via the safety valve 28 controllable by the system control unit 50 in the cleaning chamber (output “RZ1-2”). The system control unit also controls the controllable discharge valve 26 in the steam supply line to the steam nozzle/s, which is preferably used as a pure shut-off valve. Furthermore, on the steam distributor 25 or the steam supply line 33, there is a temperature sensor 66 connected to the system control unit 50. The measurement by the pressure sensor 65 and by the temperature sensor 66 can be included, e.g., in the control or regulation of the post-heating and/or the controlled steam discharge by means of a control valve (not shown) close to the steam nozzles or the discharge valve 26. In the steam supply line 33 (between output “RZ1” and the cleaning chamber), a pressure-regulating valve can be provided, which is preset for a desired steam pressure or is set by the system control unit 50 actively as needed or to the required steam pressure for the steam cleaning.

(32) It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

LIST OF REFERENCE SYMBOLS

FIG. 1A-1B

(33) 1 Steam generator 2 Core 2A Inner surface 3 First end face of the hollow cylinder 4 Second, opposite end face of the hollow cylinder 5 Water inlet 6 Spray nozzle/hollow-cone nozzle 7 Hollow-cone-shaped spray jet 8 Heating conductor (primary heating device) 9 Steam outlet 10 Reheater (supplementary heating device) 10A Body of the reheater 10B Heating element 11 Hole (secondary cavity) 12 Passage opening (radial) 13 Saturated steam 14 Dry steam 15 Insulating material 16 Reflective inner jacket 17 Air gap 18 Outer jacket 19 Spacer

FIG. 1C

(34) 1′ Steam generator 2 Core 2A Inner surface 2B Primary cavity 10 Reheater (supplementary heating device) 10A Body of the reheater 10B Heating element 11 Secondary cavity 12 Passage opening (axial) 12A Nozzle 15 Insulating material 15A Outer insulation 16 Reflective inner jacket 16A Retaining ring 17 Air gap 18 Outer jacket

FIG. 2

(35) 1 Steam generator 20 Steam generator battery 22 Feed water distributor 23 Controllable feed valve 24 Exhaust 25 Steam distributor 26 Controllable discharge valve 27, 28 Safety valves

FIG. 3

(36) 20 Steam generator battery 30 Steam cleaning system 31 Cleaning chamber 32 Steam nozzle 33 Steam supply line 36 Feed water pump 37 Feed water supply line 40 Vacuum pump 41 First filter unit 42 Second filter unit 43 Oil separator 44 Condensation unit 45 Clean tank 48 Handling device 49 Workpiece 50 System control unit

FIG. 4

(37) 1A, 1B, 1C, 1D Steam generator 8 Primary heating device 10 Reheater (supplementary heating device) 10B Secondary heating device 20 Steam generator battery 22 Feed water distributor 23 Controllable feed valve 25 Steam distributor 26 Controllable discharge valve 27 Safety valve (manually preset) 28 Controllable safety valve 33 Steam supply line 61 Primary temperature sensor (steam generator) 62 Secondary temperature sensor (steam generator) 63 Pressure sensor (feed water) 64 Overflow valve (feed water) 65 Pressure sensor (steam discharge) 66 Temperature sensor (steam discharge)