JPH0788932B2 - Reduced pressure steam generator - Google Patents

Description

Description: INDUSTRIAL APPLICABILITY The present invention relates to a reduced pressure steam generator for supplying reduced pressure steam for heating an object to be heated by condensing heat transfer of relatively low temperature steam, which is usually 100 ° C. or lower. .

In many cases, such as a reaction kettle device for drying and distilling various foods, or for decomposing, synthesizing, polymerizing, and condensing various substances in a chemical factory, the object to be heated is heated at a low temperature of 100 ° C or less . And when performing this low temperature heating,
The most influential factor on product quality and productivity is uneven heating temperature, that is, temperature unevenness.

2. Description of the Related Art Conventional low-temperature heating has been performed by generating hot water of 100 ° C. or lower in a hot water boiler and exchanging heat with an object to be heated. In addition, a steam boiler is used to generate high-temperature steam, and the steam is used to generate hot water for heat exchange.

Problems to be Solved by the Present Invention Hot water has a smaller heat capacity than steam at the same temperature, and its film heat transfer coefficient is much smaller. Therefore, there is a problem that the entire object to be heated cannot be heated uniformly, and a low temperature part is partially generated in the object to be heated, resulting in uneven heating temperature. If the heating temperature is not kept uniform, the product quality of the object to be heated cannot be kept constant, and the productivity is lowered.

Further, in the conventional hot water heating, there is a problem that the boiler, the hot water pipe, the hot water using device, and the like are likely to be corroded due to impurities and dissolved oxygen contained in the hot water, resulting in a decrease in heat transfer efficiency and poor durability.

Therefore, an object of the present invention is to make it possible to perform heating without temperature unevenness and without causing corrosion by supplying decompressed low-temperature steam instead of hot water.

Means for Solving the Problems Technical means of the present invention taken to solve the above technical problems are a steam generating means for heating a liquid and converting it into steam, and a vacuum suction means via a heater. Connect with a connecting pipe,
A liquid supply means for supplying a liquid to the steam generating means is provided between the vacuum suction means and the steam generating means, and the inside of the steam generating means, the heater and the connecting pipe are desired to be below atmospheric pressure by the vacuum suction means. In addition to maintaining the vacuum state, a pressure reducing valve is arranged between the liquid supply means and the steam generating means, and if any of the steam generating means, the connecting pipe or the heater becomes lower than a predetermined pressure, the pressure reducing valve is opened. The amount of liquid supplied to the steam generating means is increased to increase the amount of steam, and when the pressure becomes higher than a predetermined pressure, the pressure reducing valve is closed to reduce the amount of steam.

Action The vacuum suction means brings the steam generating means and the inside of the heater into a depressurized state. When the liquid is supplied to the vapor generating means from the liquid supply means, the liquid is heated and immediately the reduced pressure vapor is generated.
Reduced pressure steam is 100 ° C if the system is in a vacuum state below atmospheric pressure.
It becomes the following. The generated reduced pressure steam reaches the heater through the connecting pipe and uniformly heats the object to be heated. A part of the reduced pressure steam that has been deprived of heat by heating is drained, and is sucked from the heater by the vacuum suction means together with the remaining reduced pressure steam. The degree of pressure reduction in the steam generating means and the heater is arbitrarily adjusted by the pressure reducing valve.

Effect of the Invention According to the present invention, when heating an object to be heated at a low temperature, it is possible to heat with reduced pressure steam without using hot water, temperature unevenness does not occur, and product quality is maintained constant, High productivity can be secured.

Further, since the reduced pressure steam is used, the impurities contained therein are small, and the inside of the steam generating means, the connecting pipe and the heater are in a depressurized vacuum state, so that corrosion by oxygen is less likely to occur.

Example An example showing a specific example of the above technical means will be described.
(Refer to FIG. 1) The reduced pressure steam generator of the present invention comprises a steam generating means 1 for heating a liquid to convert it into steam, and a heater 2 for heating an object to be heated.
A vacuum suction unit 3, a connecting pipe 4 connecting the steam generation unit 1, the heater 2 and the vacuum suction unit 3, a liquid supply unit 5 for supplying a liquid to the steam generation unit 1, and a degree of pressure reduction of the apparatus. And a pressure reducing valve 13 for

The vacuum suction means 3 depressurizes the inside of the steam generating means 1, the heater 2 and the connecting pipe 4.

The vapor generating means 1 forms an evaporation heat source with the burner 7 and the combustion chamber 8, and generates reduced pressure steam with the liquid supplied from the liquid supply means 5. The liquid supply means 5 comprises a liquid supply tink 9 and a control valve 10 arranged between the liquid supply tank 9 and the steam generation means 1 for controlling the amount of liquid supply. The control valve 10 controls the liquid supply amount by the signals from the liquid level sensors 11 and 12 mounted inside the steam generating means 1. A pressure reducing valve 13 is attached to the liquid supply means 5 side of the steam generating means 1. The pressure reducing valve 13 opens when the vapor generating means 1 sucked by the vacuum sucking means 3, the connecting pipe 4 and the inside of the heater 2 become lower than the set pressure, and the valve which has been closed until now is opened and supplied. Supplying a larger amount of liquid and increasing the amount of steam to raise the decompression pressure to the set pressure. Conversely, if it is higher than the set pressure, it acts in the valve closing direction to reduce the amount of steam and maintain the set pressure. Is.

The vacuum suction means 3 is an ejector-type vacuum pump,
The liquid supply tank 9 and the suction port 17 of the spiral pump 16 are connected, the discharge port 18 of the spiral pump 16 and the suction pipe 15 of the ejector 14 are connected, and the diffuser portion is passed through a nozzle 19 at one end of the suction pipe 15.
20 is again connected to the liquid supply tank 9. Nozzle 19
A vacuum suction force is generated by the high-speed fluid passing through. In addition, the vacuum suction force generated by the ejector 14 is
Since it becomes equal to the saturation pressure at the temperature of the fluid passing through 14, cooling is performed via a temperature control valve 21 that controls the liquid temperature in the liquid supply tank 9 in order to maintain the saturation pressure, that is, the vacuum suction force with higher accuracy. Inject water. Reference numeral 22 is a temperature control valve
It is a temperature sensor that sends a liquid temperature signal in the liquid supply tank 9 to 21.

The outlet side pipe 23 of the heater 2 is connected to the ejector 14. Drain generated in the heater 2 is ejected to the outlet side pipe 23 by the ejector 14
A steam trap 25 that preferentially discharges is provided on the side.

In this embodiment, the ejector is used as the vacuum suction means 3.
Although the ejector type vacuum pump in which 14 and the volute pump 16 are combined is shown, a conventionally used vacuum pump can be used alone or in combination with the above ejector type vacuum pump. Similarly, although a boiler using a burner 7 is shown as the steam generating means 1, it is possible to generate reduced pressure steam by exchanging heat with high temperature steam or high temperature water generated by a conventional high temperature high pressure steam boiler. You can also

The reduced pressure steam generator of the present invention is capable of heating the object to be heated with the reduced pressure steam instead of the hot water by generating the reduced pressure steam with the steam generation means 1 and supplying the reduced pressure steam to the heater 2. It is possible to perform heating without temperature unevenness with a device having excellent properties.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic structure of one embodiment of the present invention. 1: Steam generation means, 2: Heater 3: Vacuum suction means, 4: Connection pipe 5: Liquid supply means, 7: Burner 9: Liquid supply tank, 13: Pressure reducing valve 14: Ejector, 16: Volute pump

Claims (1)

[Claims] 1. A steam generating means for heating a liquid to convert it into steam and a vacuum suction means are connected by a connecting pipe via a heater,
A liquid supply means for supplying a liquid to the steam generating means is provided between the vacuum suction means and the steam generating means, and the inside of the steam generating means, the heater and the connecting pipe are desired to be below atmospheric pressure by the vacuum suction means. In addition to maintaining the vacuum state, a pressure reducing valve is arranged between the liquid supply means and the steam generating means, and if any of the steam generating means, the connecting pipe or the heater becomes lower than a predetermined pressure, the pressure reducing valve is opened. A reduced pressure steam generator characterized by increasing the amount of liquid supplied to the steam generating means to increase the amount of steam, and reducing the amount of steam by closing the pressure reducing valve when the pressure becomes higher than a predetermined pressure.