JPH0544901A - Method and apparatus for producing clean steam - Google Patents

Abstract

PURPOSE:To provide steam that can be used for cleaning precision parts, etc., and is highly pure and generates no moisture condensation. CONSTITUTION:A combination of a steam generator 10 which incorporates a separator 40 in the steam header section 13 and a steam heater 20 that is used for heating further the saturated steam that is taken out of the steam generator 10 to change it into superheated steam of desired temperature constitute the subject device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing clean steam applied to a cleaning system.

[0002]

2. Description of the Related Art In recent years, the destruction of the ozone layer by CFC has become a social problem on a global scale. Freon is a chemical substance that has excellent characteristics such as being extremely chemically stable, non-toxic to humans, and non-flammable.Since its development, it has been used as a refrigerant for refrigerants and refrigerators, propellants for sprays, urethane foam and It is widely used in people's lives and industry as a foaming agent for heat insulating materials and as a cleaning agent for semiconductors and precision parts.

However, as the above-mentioned problems become apparent, a measure to totally prohibit the use of CFCs has been developed, and CFC alternatives have been studied in various fields. Among them, in the industrial field where CFCs have been used as a cleaning agent, the use of water (pure water) is being studied, and some have already been implemented.

[0004]

However, when water is used as a cleaning agent as described above, it is known that there are problems of corrosion mainly due to dissolved oxygen and process problems due to slow drying. ing. That is, in the cleaning process,
In addition to the importance of the efficiency of cleaning itself, whether or not the subsequent drying process can be performed in a short time is an important factor that determines cost and quality. However, when water is directly used as a cleaning agent, measures necessary for drying are indispensable, and since vacuum drying is currently performed, it is inevitable that equipment becomes large in size and expensive. Therefore, the inventors
In a cleaning system that uses steam, paying attention to the fact that the use of superheated steam is preferable in order to satisfy the immediate dryness,
The inventors have completed the method and apparatus of the present invention described in detail below.

[0005]

The present invention has been made in view of the above problems and uses pure water, which is passed through a steam generator consisting of a water supply header section, a heat exchange section and a steam header section, At least the steam heater and a line downstream thereof are included, which includes an operation of turning the steam into superheated steam through a steam heater, and an operation of removing at least a droplet by separator means provided in the steam header portion. A method for producing clean steam, characterized in that the temperature drop of the superheated steam is suppressed by controlling the pressure to be substantially the same as that of the supply point of the superheated steam, and a water supply header part, a heat exchange part and a separator that can be divided into three parts. A steam generator comprising a steam header section provided with means, and a steam generator comprising a saturated steam header section, a heat exchange section and a superheated steam header section for heating the steam taken out from the steam generator. A clean steam characterized by connecting to a heater, a water supply line for supplying pure water to the water supply header part, and a superheated steam supply line for taking out superheated steam to the superheated steam header part, respectively. It is a device.

[0006]

1 to 5 show an embodiment of a clean steam producing apparatus according to the present invention. In the drawing, (10) is a steam generator for pure water, (20) is a steam heater,
(30) is a control unit that controls the entire system, (4
0) is a separator means.

As shown in FIGS. 1 and 2, the steam generator (10) includes a water supply header section (11), a heat exchange section (12) and a steam header section (1).
3) are connected in this order. The water supply header (11) is connected to the water supply line (1).
Water (pure water) that has been degassed, deionized, etc. from (1)
Can be supplied. Heat exchange part (1
2) is configured by arranging a plurality of heat transfer tubes (15) in the housing (14), and these heat transfer tubes (15) are used to supply the water supply header (1
The 1) and the steam header section (13) are in communication with each other. Also,
The space (16) formed between the outer circumference of the heat transfer tube (15) and the inner circumference of the housing (14) functions as a steam jacket, and is shown via the heating steam supply line (5). The heating steam is supplied from the steam generator.

The steam header portion (13) is provided with a separator means (40) of a type which produces a coaxial swirling flow in the central portion thereof and performs centrifugal separation by the swirling flow to separate gas and liquid. 3, see FIG. 4). In the illustrated embodiment, a cylindrical rectifying member (42) surrounding the swirl vane (41) is provided, and this is attached to the central portion of the partition wall (43) provided so as to partition the steam header portion (13). It is supported in the state.

Further, collision type separator members (45) and (46) are provided above and below the separator means (40), respectively. The upper separator member (45) is a steam outlet.
A baffle plate member is attached to the inner opening of (17), and the lower separator member (46) is a baffle plate member at the end of the rectifying member (42) on the heat exchange section (12) side. It is the structure which attached.

A partition wall (43) in the steam header section (13)
A drain discharge hole (44) is formed on the upper surface of the drain discharge hole (44), and the drain discharge hole (44) collects the liquid droplets separated by the separator means (40) and the liquid droplets generated by condensation. The drain line (2) for discharging is connected.

Generally, pure water has a strong property of eluting metals and the like, and this property becomes remarkable as the temperature rises. Therefore, in the apparatus for the purpose of obtaining clean vapor for cleaning / drying as in the present invention, droplets It is important to remove the minute (saturated water).
In the present invention, the separator means as described above is incorporated in the steam header portion on the steam generator side so that such droplets can be effectively removed to obtain high dryness steam. A drain line (2) is provided for removing the droplets separated by the method from the steam header section (13) without mixing the saturated steam again. The inside of the steam generator (10) having such a structure is lined with a material having heat resistance and corrosion resistance such as PTFE (polytetrafluoroethylene), EPDM (ethylene propylene rubber), and PFA (or It is good to apply coating)
Then, there is no elution of metal, and since the accumulation of saturated water is eliminated by providing the drain line (2) as described above, it is effective to obtain pure dry saturated vapor without droplets in the vapor. ..

On the other hand, the steam heater (20) comprises a saturated steam header section (21), a heat exchange section (22) and a superheated steam header section (23) which are connected in this order. The saturated steam header section (21) is a saturated steam line with the steam header section (13) of the steam generator (10).
It is connected via (3) so that saturated steam from the steam generator (10) can be supplied. The heat exchange section (22) is constructed by disposing a plurality of heat transfer tubes (25) in the housing (24), as in the steam generator (10), and saturated steam is formed by these heat transfer tubes (25). The header part (21) and the superheated steam header part (23) are in communication with each other.

The space (26) between the outer circumference of the heat transfer tubes (25) and the inner circumference of the housing (24) receives steam for heating from a steam generator (not shown) as described above. , Acts as a steam jacket. And the superheated steam header (2
The superheated steam supply line (4) for supplying superheated steam to the subsequent process is connected to 3).

The control unit (30) controls the pressure of heating steam supplied to the steam generator (10) and the steam heater (20), and saturated steam in the steam header section (13) of the steam generator (10). By detecting the pressure, the steam temperature before and after the steam heater (20), and the water level in the heat exchange section (12) of the steam generator (10), control is performed to generate superheated steam according to the load. Specifically, the detection of each pressure is performed by the steam generator (10) and the steam heater (2
The steam temperature is detected by the pressure detectors PS1 to PS3 provided in the heat exchange sections (12) and (22) of (0) and the steam header section (13) of the steam generator (10). Temperature detectors T1 and T2 attached to the saturated steam supply line (3) and the superheated steam supply line (4) before and after, respectively, and the control unit uses the signals of these detectors to control the saturated steam supply line (3), The openings of the control valves V1 to V3 attached to the heating steam supply lines (5) and (6) to the heat exchange sections (12) and (22) are adjusted.

In FIG. 1, reference numeral (50) is a water level control tube attached to the heat exchange section (12) of the steam generator (10), and the water level control tube (50) is a heat exchange section (50). 12) Heat transfer tube (15)
This is for detecting the water level in the inside and controlling the amount of pure water supplied to the steam generator (10) based on this detected value.

In the clean steam producing apparatus having the above structure, superheated steam is produced in the following manner. First,
The raw water is subjected to water treatment such as precision filtration, deionization treatment, degassing treatment, etc. to obtain pure water substantially free of impurities, and this pure water is supplied from the water supply line (1) to the water supply header of the steam generator (10). Division (13)
To the predetermined water level (preferably within about 1/2 the height of the heat transfer tube (15)) in the heat transfer tube (15) of the heat exchange section (14). On the other hand, it is supplied from a heating steam generator (not shown) to the steam generator (10) and the heat exchange sections (12) and (22) of the steam heater (20).

As a result, the pure water supplied from the water supply header section (11) of the steam generator (10) to the heat exchange section (12) is generated by the steam generator.
In (10), it becomes steam (saturated steam) and steam header section (1
3) From the saturated steam supply line (3) to the steam heater (20)
Is supplied to the saturated steam header section (21). In this case, the saturated steam supply line (3), the steam heater (20), and the superheated steam supply line (4) are controlled to have almost the same pressure so that the temperature drop at the point of use does not occur.

In the steam generator (10), the steam that has passed through the heat exchange section (12) is separated into each separator in the steam header section (13), that is, a collision type separator member (46), separator means (40),
In addition, impurities such as saturated water (droplets) are removed by the collision type separator member (45), and dry saturated vapor with high cleanliness is obtained. Then, the dry saturated steam is further heated in the heat exchange section (22) of the steam heater (20) and is supplied as superheated steam from the superheated steam supply line (4) to a cleaning unit or the like in a subsequent step.

In the above-mentioned apparatus for producing clean steam,
When controlling the superheated steam temperature, the control valve V3 attached to the heating steam supply line (6) to the heat exchange section (22) of the steam heater (20) is operated. At this time, in order to raise the superheated steam temperature, the control valve V3 may be operated so as to increase the heating steam pressure supplied to the heat exchange section (22) of the steam heater (20). The control valve V3 may be operated in reverse. In this case, the amount of steam does not change.

On the other hand, when controlling the amount of superheated steam, the control valve V1 in the saturated steam supply line (3) is operated to increase (or decrease) the flow rate of saturated steam flowing into the steam heater (20). )
Alternatively, the heating steam pressure supplied to the heat exchange section (12) of the steam generator (10) may be adjusted to adjust the amount of saturated steam generated from the steam generator (10) itself. That is, in order to increase the amount of saturated steam generated, the heat exchange section (1
Control valve V2 to increase the heating steam pressure supplied to 2)
The control valve V2 may be operated in the opposite direction when the control valve V2 is decreased. In addition, the above water level control cylinder (50)
The amount of evaporation may be controlled by adjusting the water level in the heat transfer tube (15) according to the water level detection signal from.

Further, the temperature detectors T1 and T2 detect the temperature difference between the saturated steam supply line (3) and the superheated steam supply line (4) before and after the steam heater (20), and thereby each control valve V1. .About.V2 may be controlled.

As explained above, according to the apparatus for producing clean steam of the present invention, it is possible to obtain extremely clean superheated steam which is suitable for cleaning precision parts and which does not substantially contain impurities. The drying step can also be performed in an extremely short time.

In the above description, the separator means provided in the steam header section of the steam generator is the swirl vane (41), but in the present invention, a coaxial swirl flow is generated in the steam header section (13). Any material may be used as long as it is produced and the impurities are separated by centrifugation. For example, other than the above-mentioned materials, the materials shown in FIGS. 6 and 7 may be used. That is, this separator means is a plurality of nozzles (47) is arranged on the flat plate (48) so that the blowing direction thereof creates a swirl flow in the steam header portion (13), and these nozzles (47) It is configured such that droplets and the like in the saturated vapor are centrifugally separated by ejecting the saturated vapor.

In the above description, an example of obtaining superheated steam for cleaning electronic devices, ultra-precision parts, etc. is used, but depending on the cleaning purpose, corrosiveness, etc. In practice, it is preferable to change the cleanliness of steam and the cleanliness of pure water to be supplied. In addition, the clean (superheated) steam obtained by the apparatus of the present invention can be used for cleaning as described above, and can also be used for other applications such as sterilization.

[0025]

EFFECT OF THE INVENTION According to the apparatus for producing clean steam of the present invention, it is possible to obtain clean (clean) superheated steam that is substantially free of impurities and is suitable for cleaning precision parts. The subsequent drying process can be shortened in time.

With such an apparatus for producing clean steam, it becomes possible to use harmless water as a cleaning agent instead of CFC, which causes environmental damage.
It can also make a great contribution from the viewpoint of environmental protection.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a clean steam manufacturing apparatus according to the present invention.

FIG. 2 is a side view including a partial fracture surface of the steam generator in the embodiment of FIG.

FIG. 3 is a plan view showing details of separator means incorporated in the steam generator of FIG.

FIG. 4 is an enlarged sectional view of a main part of the steam generator of FIG.

FIG. 5 is a side view including a partial fractured surface of the steam heater in the embodiment of FIG.

FIG. 6 is a plan view showing another embodiment of the separator means incorporated in the steam generator of FIG.

7 is a side view of the separator means shown in FIG.

[Explanation of symbols]

 (1) ・ ・ ・ Water supply line (4) ‥‥ Superheated steam supply line (10) ‥‥ Steam generator (13) ‥‥ Steam header (20) ‥‥ Steam heater (30) ‥‥ Control unit (40)・ ・ ・ Separator means (41) ・ ・ ・ Swirling vane (42) ‥‥ Straightening member (45) ‥ ‥ Colliding type separator member (46) ‥ Colliding type separator member

Claims (4)

[Claims] 1. Pure water is used, and this is supplied to the water supply header section (1
0), through a steam generator (10) consisting of a heat exchange section (12) and a steam header section (13), and an operation of turning it into superheated steam via a steam heater (20), and at least the steam header section (13). ) In which the droplet means is removed by the separator means (40), and at least the steam heater (20) and the line (4) on the downstream side of the steam heater (20) are substantially connected to the superheated steam supply point. A method for producing clean steam, characterized in that the temperature drop of superheated steam is suppressed by controlling to the same pressure. 2. A steam generator (10) comprising a steam header part (13) having a water supply header part (10), a heat exchange part (12) and a separator means (40) which can be divided into three parts, and this steam. Generator (10)
In order to heat the steam taken out from the saturated steam header part (21), the heat exchanger (22) and the steam heater (20) consisting of the superheated steam header part (23) are connected, and the water supply header part ( The water supply line (1) for supplying pure water is provided at 10), and the superheated steam supply line for taking out superheated steam is provided at the superheated steam header section (23).
An apparatus for producing clean steam, characterized in that (4) is connected to each other. 3. The separator means (40) according to claim 1,
An apparatus for producing clean steam, characterized in that a swirl vane (41) for generating a coaxial swirling flow is provided in a steam header portion (13). 4. An apparatus for producing clean steam, characterized in that a collision type separator member (45) (46) is provided on at least one of the steam inflow side and the outflow side of the separator means (40) of claim 3. ..