JPH0788935B2 - Vacuum steam generator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum steam generator that supplies vacuum steam for efficiently heat-treating an object to be heated at a temperature of about 100 ° C or lower.

In various production processes, heat treatment is widely and generally performed, but such heat treatment often heats the object to be heated at a high temperature of 100 ° C. or more, and directly uses steam from the boiler. Usually, the heating is performed by using a pressurization type heating device at atmospheric pressure or higher.

On the other hand, in various chemical factories and food factories, there are many applications in which an object to be heated must be heated at a relatively low temperature of 100 ° C or less in order to maintain product quality.

2. Description of the Related Art Conventionally, a vacuum steam generator as disclosed in Japanese Patent Laid-Open No. 64-6603 has been used. This is because the pressure reducing valve is arranged on the primary side of the indirect heating container, and the suction pressure generated in the ejector section can be arbitrarily set by controlling the temperature of the fluid passing through the nozzle of the ejector on the secondary side. A vacuum steam generator connected to a vacuum pump, and by making the suction pressure generated in the ejector section and the set pressure of the pressure reducing valve approximately the same, steam can be excessively supplied to the indirect heating container through the pressure reducing valve. Therefore, it is possible to efficiently generate vacuum vapor without vapor loss. Further, in the actual production process, the operating temperature, that is, the vacuum vapor pressure must be changed in many cases due to the efficiency of production or the diversification of production targets.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the case of the above-mentioned conventional technique, each time the pressure reducing valve set pressure is changed, the temperature setting of the fluid passing through the nozzle must be changed in accordance with this change, and the pressure reducing valve is particularly frequently frequented. When the set pressure, that is, the operating temperature is changed, it is complicated, and it takes time to change, resulting in a decrease in productivity.

Further, in order to automatically set the temperature of the fluid passing through the nozzle according to the pressure setting of the pressure reducing valve, a device or means for converting the pressure into the temperature is required, which makes the device complicated and expensive. There is a problem that it becomes a thing.

Therefore, the technical problem of the present invention is that the change of the temperature setting of the fluid passing through the nozzle of the ejector and the change of the set pressure of the pressure reducing valve in accordance with the change of the operating temperature, that is, the vacuum vapor pressure are easy and short with a simple mechanism. To be able to do it in time.

MEANS FOR SOLVING THE PROBLEM The technical means of the present invention taken to solve the above-mentioned problem is to arrange a pressure reducing valve on the primary side of a heating container and to suck a diffuser of an ejector and a volute pump on the secondary side. Control that opens and closes in accordance with the water temperature in the tank by providing a cooling water supply passage for communicating cooling water to the tank by communicating the ejector with the discharge port of the spiral pump through the tank In a vacuum vapor generator that is provided with a valve to control the temperature of the fluid circulating through the ejector and the centrifugal pump, a secondary pressure detection diaphragm is attached to the pressure reducing valve, and one surface of the secondary pressure detection diaphragm is attached. One end of the pressure setting spring is made to act in a tensioned state, and the other end of the pressure setting spring is connected to a driving diaphragm via a connecting rod, so that one surface of the driving diaphragm and the above-mentioned It is connected to the vicinity of the zector by a pressure communication pipe.

When changing the working temperature, that is, the vacuum steam pressure, cooling water is supplied or stopped through the control valve in the tank so that the saturation temperature becomes substantially equal to the vacuum pressure. When the temperature of the water circulating through the ejector and the centrifugal pump is controlled, the ejector section becomes a pressure equal to the desired vacuum pressure, and this pressure is transmitted to the pressure drive section for changing the set pressure of the pressure reducing valve via the pressure communication pipe. Then, the pressure drive section is displaced to set the set pressure of the pressure reducing valve to a pressure substantially equal to the vacuum pressure of the ejector section.

Effect of the Invention When changing the operating temperature of the heating device, the set pressure of the pressure reducing valve is also controlled at the same time by simply controlling the water temperature in the tank, so that frequent changes in the operating temperature, that is, changes in the vacuum setting pressure Also, the temperature of the fluid can be changed easily and in a short time.

Further, the mechanism can be simplified by simply connecting the ejector section and the pressure drive section of the pressure reducing valve.

Example An example showing a specific example of the above technical means will be described.
(Refer to FIG. 1 and FIG. 2) FIG. 1 is a configuration diagram of a vacuum steam generator of the present invention. A pressure reducing valve 3 for adjusting the steam pressure is attached to a steam passage 2 for supplying steam to the heating device 1. The pressure reducing valve 3 (see FIG. 2) is a vacuum pressure reducing valve that operates the pressure setting spring 51 in a tensioned state, and a diaphragm 56 for detecting a secondary pressure is provided in the valve portion 3 having an inlet 52, an outlet 53 and a valve 54. And a pressure drive unit 19. The pressure drive unit 19 connects the drive diaphragm 58 and the pressure setting spring 51 with a connecting rod 57 to form a drive diaphragm.
The pressure communication pipe 60 is connected to the upper part of 58.

The outlet side end of the steam passage 2 communicates with the ejector unit 5. The diffuser part 9 of the ejector part 5 and the suction port 7 of the spiral pump 6 are communicated with each other through the tank 8, and the discharge port 10 of the spiral pump 6 and the nozzle part 12 of the ejector part 5 are communicated with each other by the circulation passage 11.

The other end of the pressure communication pipe 60 is connected to the vicinity 61 of the ejector 5. Therefore, the pressure in the vicinity of the ejector 5 is transmitted to the pressure drive unit 19 of the pressure reducing valve 3 through the pressure communication pipe 60.

A discharge passage 13 for discharging condensed water and cooling water is provided at one end of the circulation passage 11 and a control valve 14 for adjusting the discharge amount.
Install. The control valve 14 is not always necessary when there is no large change in the discharge amount. A cooling water supply passage 15 for supplying cooling water to the tank 8 is attached via a control valve 16. At the bottom of the tank 8, the temperature of the water in the tank and then the nozzle 12
Temperature sensor 17 for detecting the temperature of the fluid passing through it
Install. The actuator section 18 of the control valve 16 and the temperature sensor 17 are connected to the control section 21 by a signal line 20. Control unit
Reference numeral 21 includes a setting unit (not shown) for setting the water temperature in the tank 8 and a transmission unit (not shown) for issuing an opening / closing signal to the actuator unit 18 of the control valve 16 according to the setting signal.

A signal from a water level sensor 23 that detects the water level in the tank 8 is input to the actuator portion 22 of the control valve 14 attached to the discharge passage 13 to adjust the discharge amount. A communication pipe 24 communicating with the atmosphere is attached to the upper portion of the tank 8 via a valve 25.

When setting the operating temperature of the heating device 1, that is, the vacuum vapor pressure, when the set pressure is input from the control unit 21, the required water temperature in the tank 8, that is, the suction pressure generated in the nozzle unit 12 of the ejector 5 passes through the nozzle unit 12. The cooling water is injected or stopped from the control valve 16 so that it becomes equal to the saturation pressure at the temperature of the fluid to be heated, and the set pressure and the saturation pressure become the same. The set pressure in the ejector section 5 is 60
Is transmitted to the pressure drive unit 19 of the pressure reducing valve 3, the set pressure of the pressure reducing valve 3 becomes substantially equal to the set pressure of the vacuum vapor, and the object to be heated can be heated at a desired temperature via the heating device 1. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a vacuum steam generator of the present invention,
FIG. 2 is a schematic sectional view of the pressure reducing valve shown in FIG. 1: Heating device, 3: Pressure reducing valve 5: Ejector part, 6: Volute pump 8: Tank, 9: Diffuser part 12: Nozzle part, 15: Cooling water supply passage 16: Control valve, 17: Temperature sensor 19: Pressure drive Part, 21: control part 51: pressure setting spring, 52: inlet 53: outlet, 54: valve 56: secondary pressure detection diaphragm 58: drive diaphragm 60: pressure communication pipe, 61: near ejector

Claims (1)

[Claims] 1. A pressure reducing valve is arranged on the primary side of a heating container, and a diffuser of an ejector and a suction port of a spiral pump are connected to each other on a secondary side through a tank, and an ejector and a discharge port of a spiral pump are connected to each other. Then, a cooling water supply passage for supplying cooling water to the tank is provided, and a control valve that opens and closes according to the water temperature in the tank is provided in the passage to control the temperature of the fluid circulating through the ejector and the spiral pump. In the vacuum steam generator, a secondary pressure detection diaphragm is attached to the pressure reducing valve, and one end of the pressure setting spring is applied to one surface of the secondary pressure detection diaphragm in a tensioned state,
The other end of the pressure setting spring is connected to a drive diaphragm via a connecting rod, and one surface of the drive diaphragm and the vicinity of the ejector are connected by a pressure communication pipe. .