JPH0252902A - Reduced pressure steam generator - Google Patents

Abstract

PURPOSE:To supply reduced pressure and low temperature steam by furnishing a liquid feeding device that feeds liquid to between a vacuum aspirating device and a steam generator, and a pressure reducing valve that controls the degree of reduced pressure in an entire device. CONSTITUTION:A vacuum aspirating device 3 produces a reduced pressure state inside a steam generator 1, a heater 2, and a connecting pipe 4. The steam generator 1 produced reduced pressure steam from liquid supplied by a liquid feeding device 5. The liquid feeding device consists of a liquid feeding tank 9 and a control valve 10 that controls the feeding rate of liquid according to signals from liquid level sensors 11 and 12 installed inside the steam generator 1. A pressure reducing valve 13 mounted inside the steam generator 1 keeps a set pressure by increasing or decreasing the amount of steam when the pressure inside the steam generator 1, the connecting pipe 4, and the heater 2, which are sucked by the vacuum aspirating device 3, becomes higher or lower than the set pressure. A combination of an ejector 14 and a centrifugal pump 16, for example, is applied as the vacuum aspirating device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reduced pressure steam generator that supplies reduced pressure steam for heating an object to be heated by condensation heat transfer of relatively low temperature steam, usually below 100°C.

In reaction kettle equipment used for drying and distilling various foods, or for decomposing, synthesizing, polymerizing, and condensing various substances in chemical factories, there are cases in which the objects to be heated are heated at low temperatures of 100°C or less. There are many. When this low-temperature heating is performed, the factor that has the greatest effect on product quality and productivity is non-uniformity of the hO heating temperature, that is, temperature unevenness.

Prior Art Conventional low-temperature heating was performed by generating hot water of 100'C or less in a hot water boiler and exchanging heat with the object to be heated. In addition, a steam boiler was used to generate high-temperature steam, and the steam was used to create hot water for heat exchange.

Problems to be Solved by the Invention Hot water has a smaller heat capacity than steam at the same temperature, and its film heat transfer coefficient is also much smaller. Therefore, the entire object to be heated cannot be heated uniformly, and there is a problem in that the object to be heated has local low-temperature parts, resulting in uneven heating temperature. If the heating temperature is not maintained uniformly, there will be problems such as the inability to maintain a constant product quality of the heated object and a decrease in productivity.

In addition, in conventional hot water heating, impurities and dissolved oxygen contained in the hot water tend to cause corrosion in boilers, hot water piping, hot water usage equipment, etc., leading to problems such as reduced heat transfer efficiency and poor durability.

Therefore, it is an object of the present invention to supply low-temperature steam under reduced pressure instead of hot water, thereby enabling heating without temperature unevenness and corrosion.

Means for Solving the Problems The technical means of the present invention taken to solve the above problems is to connect a steam generation means for heating a liquid to steam and a vacuum suction means through a heater. A liquid supply means for supplying liquid to the steam generation means and a pressure reduction valve for adjusting the degree of pressure reduction of the entire apparatus are provided between the vacuum suction means and the steam generation means.

The vacuum suction means creates a reduced pressure inside the steam generation means and the heater. When liquid is supplied from the liquid supply means to the steam generation means, the liquid is heated and immediately generates reduced pressure steam.

Reduced pressure steam is 100% if the system is in a vacuum state below atmospheric pressure.
'C or below. The generated reduced pressure steam passes through the connecting pipe and reaches the heater, uniformly heating the object to be heated. Part of the reduced pressure steam that has been deprived of heat by heating is converted into drain, and is sucked together with the remaining reduced pressure steam from the heater by the vacuum suction means. The degree of pressure reduction within the steam generation means and heater is arbitrarily adjusted by a pressure reduction valve.

Effects of the Invention According to the present invention, when heating an object to be heated at a low temperature, it can be heated with reduced pressure steam without using hot water, temperature unevenness does not occur, product quality can be maintained constant, High productivity can be ensured.In addition, by using reduced pressure steam, there are fewer impurities, and the steam generation means, connecting pipes, and heater are in a vacuum state, which prevents corrosion due to oxygen. It's hard to do.

Embodiment An embodiment illustrating a specific example of the above technical means will be described. (
(See Figure 1) The reduced-pressure steam generation device of the present invention includes a steam generation means 1 that heats a liquid and converts it into steam, a heater 2 that heats an object to be heated, a vacuum suction means 3, and a steam generation means 1. It consists of a connecting pipe 4 that connects the heater 2 and the vacuum suction means 3, a liquid supply means 5 that supplies liquid to the steam generation means 1, and a pressure reducing valve 13 that adjusts the degree of pressure reduction of the device.

The vacuum suction means 3 brings the insides of the steam generation means 1, the heater 2, and the connecting pipe 4 into a reduced pressure state.

The steam generating means 1 uses a burner 7 and a combustion chamber 8 to form an evaporative heat source, and generates reduced pressure steam using the liquid supplied from the liquid supply means 5. The liquid supply means 5 includes a liquid supply tank 9 and a control valve 10 arranged between the liquid supply tank 9 and the steam generating means 1 to control the supply ti, m.

The control valve 10 controls the amount of liquid supplied by a signal from a liquid level sensor 11.12 installed in the steam generating means 1. A pressure reducing valve 13 is attached to the liquid supply means 5 side of the steam generation means 1. When the internal pressure of the steam generating means 1, the connecting pipe 4, and the heater 2 sucked by the vacuum suction means 3 becomes lower than the set pressure, the pressure reducing valve 13, which was previously closed, opens and starts supplying liquid. A device that supplies a larger amount of steam, increases the amount of steam, and raises the reduced pressure to the set pressure. Conversely, if the pressure becomes higher than the set pressure, it acts in the direction of closing the valve, decreasing the amount of steam and maintaining the set pressure. It is.

The vacuum suction means 3 is an ejector-type vacuum pump,
The liquid supply tank 9 and the suction port 17 of the centrifugal pump 16 are connected, the discharge port 18 of the centrifugal pump 16 and the suction pipe 15 of the esector 14 are connected, and the liquid is supplied to the differential user section 208 again through the nozzle 19 at one end of the suction pipe 15. It is connected to tank 9. The high velocity fluid passing through the nozzle 19 creates a vacuum suction force. In addition, since the vacuum suction force generated by the ejector 14 is equal to the saturation pressure at the temperature of the fluid passing through the ejector 14, in order to maintain the saturation pressure, that is, the vacuum suction force more accurately, the liquid supply tank 9 Cooling water is injected through a temperature control valve 21 that controls the temperature of the liquid inside. Reference numeral 22 denotes a temperature sensor that sends a liquid temperature signal in the liquid supply tank 9 to the temperature control valve 21.

The outlet side pipe 23 of the heater 2 is connected to the ejector 14. The outlet side pipe 23 is provided with a steam trap 25 for preferentially discharging the drain generated in the heater 2 to the ejector 14 side.

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

This reduced-pressure steam generator generates reduced-pressure steam with the steam generation means 1 and supplies it to the heater 2, so that the object to be heated can be heated with reduced-pressure steam instead of hot water, and is corrosion-resistant and durable. The device has excellent properties and can heat evenly.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic structure of an embodiment of the present invention. 1: Steam generation means 2: Heater 3: Vacuum suction means 4: Connecting pipe 5: Liquid supply means 7: Burner 9: Liquid supply tank 13: Pressure reducing valve

Claims (1)

[Claims] 1. A steam generating means that heats a liquid to convert it into steam and a vacuum suction means are connected by a connecting pipe through a heater, and liquid is supplied to the steam generating means between the vacuum suction means and the steam generating means. A reduced-pressure steam generator equipped with a liquid supply means to provide liquid and a pressure-reducing valve to adjust the degree of pressure reduction of the entire device.