JP2699042B2 - Steam heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam heating apparatus for efficiently heating an object to be heated with steam at about 100.degree. C. while sucking the inside of a heating vessel with a vacuum pump. In chemical factories, food factories, medical products factories, etc., there are many applications in which a heated object must be heated at a relatively low temperature of about 100 ° C in order to maintain product quality. Heating has conventionally been performed mostly using hot water. However, since hot water has a small amount of heat and tends to cause uneven heating, and equipment for producing and storing hot water is relatively large-scale, heating to about 100 ° C. using low-pressure steam has recently been performed. Is being done.

[0002]

2. Description of the Related Art An example of conventional low-temperature steam heating is disclosed in, for example, JP-A-1-277101. The suction pressure generated in the ejector unit can be arbitrarily set by disposing a pressure reducing valve on the primary side of the heating vessel and controlling the temperature of the fluid passing through the nozzle of the ejector on the secondary side. A vacuum steam generator connected to an ejector-type vacuum pump. An actuator section is attached to a pressure reducing valve, and a setting signal is sent to the actuator. Cooling water control is performed based on the setting signal and the water temperature in the tank. A control unit that sends an open / close signal to the valve is provided.By setting the suction pressure generated in the ejector unit and the set pressure of the pressure reducing valve to be the same, excessive supply of steam to the heating vessel through the pressure reducing valve is achieved. Thus, efficient low-temperature steam heating without steam loss is possible.

[0003]

In the case of the above-mentioned prior art, there is a problem that the heating temperature greatly varies with the variation of the shape and size of the heating vessel or the quantity and temperature of the object to be heated. there were. This is because the suction pressure generated in the ejector section is equal to the set pressure of the pressure reducing valve, so that the temperature of the heated steam supplied from the pressure reducing valve and the saturation temperature of the fluid flowing down the ejector section are different. This is because there is almost no difference between them, and the actual heating temperature fluctuates depending on the size of the heating container, and the actual heating temperature also fluctuates immediately due to the change in the load to be heated.

Further, in the case of the above prior art, since the temperature of the object to be heated is not directly detected and controlled, the heating temperature cannot be maintained at a predetermined value with higher accuracy. Fluctuations in the heating temperature must be prevented as much as possible, especially in the case of chemical products, foods, medical products, etc., in order to cause a change in product quality with a slight temperature change.

Accordingly, a technical object of the present invention is to maintain a constant heating temperature with high accuracy even when there is a change in the size and shape of the heating vessel or the load to be heated such as the amount and temperature of the object to be heated. Is to obtain a steam heating device which can be used.

[0006]

Means for Solving the Problems The technical means of the present invention taken to solve the above problems is to arrange a steam control valve on the primary side of the heating vessel, and to provide an ejector on the secondary side of the heating vessel. A cooling water supply passage for supplying cooling water to the tank by connecting the diffuser and the suction port of the circulation pump via a tank, communicating the ejector with the discharge port of the circulation pump, and providing the cooling water supply passage; An ejector-type vacuum pump equipped with a cooling water control valve is installed in the pump, a ejector, a circulating pump, and a fluid temperature detecting member that detects the temperature of the fluid circulating in the tank are installed. A control unit that sends a setting signal to the actuator and sends an opening / closing signal to the cooling water control valve based on the setting signal and a detection signal from the fluid temperature detection member. A temperature setter that can set the temperature of the fluid circulating in the tank to a desired value lower than the steam temperature supplied from the steam control valve to the heating vessel, and the temperature of the object to be heated in the heating vessel. And a second control unit for issuing a second open / close signal to the steam control valve and the cooling water control valve based on a detection signal from the heated object temperature detecting means. Things.

[0007]

[Action] When the heating steam temperature is changed by changing the set pressure of the steam control valve, the control unit operates the steam control valve.
The cooling water control valve for changing the temperature of the circulating fluid passing through the nozzle is opened and closed based on the setting signal and the detection signal from the fluid temperature detecting member. In this case, by providing the temperature setting device, the temperature of the fluid circulating through the ejector, the circulation pump, and the tank becomes lower by a desired value than the steam temperature supplied to the heating vessel from the steam control valve. Cooling water can be supplied as follows.

For example, when the heating vessel is small and the variation in the load to be heated is small, the temperature of the circulating fluid of the nozzle becomes about 1 to 3 degrees lower than the temperature of the steam supplied from the steam control valve. As described above, by setting with the temperature setting device, and when the heating vessel is large and the fluctuation of the load to be heated is large, the temperature of the nozzle circulating fluid is set to 5 ° C. to 8 ° C. lower than the steam temperature from the steam control valve. By setting the temperature to be lower by about C, the heating temperature in the heating vessel by steam can be accurately maintained at a constant value.

[0009] Further, by providing a heated object temperature detecting means for detecting the temperature of the heated object, and providing a second control section for issuing a second open / close signal to the steam control valve and the cooling water control valve,
The temperature of the object to be heated is constantly detected, and the temperature of the heated steam to be supplied and the suction pressure at the ejector can be controlled to optimal values, and the temperature of the object to be heated can be accurately maintained at a predetermined value. .

[0010]

An embodiment showing a specific example of the above technical means will be described (see FIG. 1). FIG. 1 is a configuration diagram of the steam heating device of the present invention. A steam control valve 3 is attached to a steam passage 2 that supplies steam to the heating vessel 1. An actuator 19 is attached to the steam control valve 3. As the steam control valve 3, a temperature sensor 3 that can detect a steam temperature in the steam passage 2.
When 0 is provided, a temperature control valve can be used,
When a pressure sensor (not shown) capable of detecting a steam pressure is provided instead of the temperature sensor 30, a pressure control valve can be used. The controller 19 of the steam control valve 3 and the temperature sensor 30 are connected to the first controller 3.
Connect to 1.

A heating object supply pipe 33 for supplying an object to be heated is connected to a lower portion of the heating vessel 1 via a valve 34. A heating object take-out pipe 35 for taking out an object to be heated is connected to an upper portion of the heating vessel 1 through a valve 36. Heated object supply pipe 33
Temperature sensors 37 and 38 for detecting the respective temperatures are attached to the heating object take-out pipe 35. Although not shown, the temperature sensors 37 and 38 and the valves 34 and 36 are connected to a first controller 31 including a second control unit.

The outlet side end of the steam passage 2 communicates with an ejector section 5 of an ejector type vacuum pump 4. The ejector-type vacuum pump 4 communicates a diffuser section 9 of the ejector section 5 with a suction port 7 of a spiral pump 6 serving as a circulation pump via a tank 8, and a discharge port 10 of the spiral pump 6 and an ejector section. The nozzle part 12 of the part 5 is formed so as to communicate with the circulation passage 11. At one end of the circulation passage 11, a discharge passage 13 for discharging condensed water and cooling water as condensed water is provided, and a control valve 14 for adjusting a discharge amount is attached. When there is no large variation in the discharge amount, the control valve 14 is not always necessary. A cooling water supply passage 15 for supplying cooling water to the tank 8 can be connected via a cooling water control valve 16.
At the bottom of the tank 8, a temperature sensor 17 as a fluid temperature detecting means for detecting the temperature of the water passing through the tank 8 and thus the temperature of the fluid passing through the swirl pump 6, the nozzle section 12, and the ejector section 5 is attached. The actuator 18 of the cooling water control valve 16 and the temperature sensor 17 are connected to a second controller 21.
Connect with The temperature controller 32 is connected to the second controller 21 and also to the first controller 31 of the steam control valve 3. In the first controller 31,
A temperature setting unit (not shown) for transmitting a set temperature signal to the actuator 19 of the steam control valve 3 is incorporated. Further, the second controller 21 has a calculation unit (not shown) for calculating the required water temperature in the tank 8 from the relationship between the set temperature in the first controller 31 and the set temperature in the temperature setting unit 32. ), The cooling water control valve 16 based on the calculation result and the water temperature in the tank 8
The transmitter 18 has a built-in transmitter (not shown) for issuing a required opening / closing signal. The first controller 31 and the second controller 21 constitute a control unit.

A communication pipe 24 communicating with the atmosphere is attached to the upper part of the tank 8 via a valve 25. The valve 25 and the control valve 14 provided in the discharge passage 13 can be remotely controlled by a controller similarly to the steam control valve 3 and the cooling water control valve 16.

When setting the steam heating temperature of the heating vessel 1, the temperature of the steam control valve 3 is set to a predetermined value by the temperature setting section of the first controller 31. The first control
The second controller 2 so that the temperature set in the temperature controller 32 is lower than the temperature set in the
An opening / closing signal is issued from 1 to the cooling water control valve 16, and the temperature of the fluid in the tank 8, that is, the temperature of the fluid passing through the ejector 5 is maintained at a desired value. When the temperature of the fluid passing through the ejector 5 becomes lower than the temperature of the steam supplied from the steam control valve 3 to the heating vessel 1 by a desired value,
Even when the size of the heating container 1 changes or the amount or temperature of the object to be heated changes, the fluctuation of the steam heating temperature is reduced, and the heating temperature can be kept constant.

The temperature of the object to be heated is constantly detected by the temperature sensors 37 and 38, and the required temperature of the heated steam is supplied through the steam control valve 3, and at the same time, the suction pressure of the ejector 5 is controlled. The temperature of the object to be heated can be maintained at a predetermined value with high accuracy.

[0016]

As described above, according to the present invention, the provision of the temperature setting device allows the temperature of the circulating fluid passing through the nozzle to be higher than the temperature of the steam supplied from the steam control valve to the heating vessel. The temperature of the circulating fluid can be set according to the size and shape of the heating vessel or the fluctuations in the amount and temperature of the object to be heated, and the steam heating temperature can be accurately maintained at a constant value. be able to.

The temperature of the object to be heated is constantly detected by the object temperature detecting means and the second control unit, and the temperature of the heated steam to be supplied and the suction pressure of the ejector are adjusted to the optimum values. The temperature of the object to be heated can be maintained at a predetermined value with high accuracy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a steam heating device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating container 2 Steam passage 3 Steam control valve 4 Ejector type vacuum pump 5 Ejector part 6 Swirl pump 8 Tank 9 Diffuser part 15 Cooling water supply passage 16 Cooling water control valve 17 Temperature sensor 18, 19 Actuator Reference numeral 21 Second controller 31 First controller 32 Temperature setting device 33 Heated object supply pipe 35 Heated object removal pipe 37, 38 Temperature sensor

Claims (1)

(57) [Claims] 1. A steam control valve is provided on a primary side of a heating vessel,
The diffuser of the ejector and the suction port of the circulating pump communicate with the secondary side of the heating vessel via a tank, and the ejector communicates with the discharge port of the circulating pump. An ejector-type vacuum pump provided with a cooling water supply passage for supplying, a cooling water control valve provided in the passage, and a fluid temperature detecting member for detecting a temperature of a fluid circulating in the ejector, the tank and the circulation pump are provided. At the same time, a control unit that attaches an actuator to the steam control valve, sends a setting signal to the actuator, and sends an open / close signal to the cooling water control valve based on the setting signal and a detection signal from the fluid temperature detection member. In the equipment provided, set the temperature of the fluid circulating through the ejector, the tank, and the circulation pump to a desired value lower than the temperature of the steam supplied from the steam control valve to the heating vessel. Provided with a possible temperature setter,
A heating target temperature detecting means for detecting a temperature of the heating target in the heating vessel is provided, and a second opening / closing signal is sent to the steam control valve and the cooling water control valve by a detection signal from the heating target temperature detecting means. A steam heating device, comprising a second control unit that emits light.