JPH0133758B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Objectives) The present invention relates to a device for exhausting air accumulated in a steam space of a steam heating appliance.

Steam heating equipment generally heats an object placed in a hollow container using steam that is continuously supplied into the container, and the object to be heated is a device that flows inside the container. This may be a type of piping, or it may be a direct product.

Examples of equipment include autoclaves for drying cement, etc., sterilizers for medical equipment, and vulcanization kettles used for processing rubber.

A large amount of air that was present in the inlet piping system flows into the steam heating equipment when steam is sent and started. Also, during operation, air separated from water when steam is generated flows in together with the steam.

When air accumulates in the steam space of a steam heating device,
Air needs to be evacuated as the temperature of the steam space decreases and the heating efficiency decreases.

Therefore, conventionally, as shown in FIG. 2, an exhaust valve 51 that is self-operating thermostatically is attached to the exhaust passage 60 at the upper part of the steam space 50, so that the temperature of the steam space 50 is lowered to a predetermined value or less. When it got wet, I opened the valve to let the air out.

The steam passes through a passage 54 and is supplied to the steam heating device 53 after being pressure regulated by a pressure reducing valve 59, and the condensate generated there passes through a passage 55 to a steam trap 56.
is discharged. The material is transferred from the passage 57 to the heating device 53
The product enters and is heated and exits through passage 58.

However, there was a problem in that a large amount of steam escaped during exhaust.

This is because conventional exhaust valves operate with a bimetal or a bellows filled with heat-sensitive fluid. In other words, the response of these thermosensitive members is slow to temperature changes, so when the valve is closed, the temperature of the steam space will be much higher than when the valve is open, so the temperature must be at least 15 degrees C lower than the saturated steam temperature. The valve must be set to open when the air mixture ratio is between 30 and 50%. In particular, in the case of bellows, the opening/closing valve temperature is determined by the sealed fluid.
Since it is difficult to change the set temperature,
A large amount of steam leaked out during exhaust.

Therefore, if the air mixing ratio in the steam space can be maintained at a low value, the above problem is solved.

The technical problem of the present invention is to make the opening/closing valve operation of the exhaust system sensitive to changes in the temperature of the steam space, and also to be able to adjust the set temperature so that the valve opens/closes at a temperature closer to the saturated steam temperature. It is to be.

(Structure) The technical means of the present invention taken to solve the above problem is to attach an electric sensor that detects the temperature of the steam space and an electric sensor that detects the pressure to the steam heating equipment, and to An exhaust valve driven by a valve actuator is placed in a passage that exhausts the air accumulated in the equipment, and a controller that stores the relationship between steam pressure and a temperature slightly lower than the saturation temperature for that pressure is placed, and the Therefore, the pressure is automatically converted into a corresponding temperature in the controller and the temperature is used as a reference value, and the valve actuator is controlled so that the signal from the temperature sensor approaches the reference value determined in the controller. The exhaust valve is opened when the steam space is below the standard value.

The action is as follows. Electrical pressure sensors sensitively detect pressure changes in the steam space and send signals to the controller. In the controller, a temperature corresponding to the pressure is calculated from the relationship between the stored pressure and a temperature slightly lower than the saturation temperature for that pressure, and this is used as a reference value. On the other hand, electrical temperature sensors also sensitively detect temperature changes in the steam space and send signals to the controller. The controller compares the signal from the temperature sensor with the reference value, and if the signal value from the temperature sensor is smaller than the reference value, it sends an instruction signal to the actuator to open the valve, and if it is larger, sends an instruction signal to the actuator to close the valve. The valve actuator drives the exhaust valve according to the instruction signal.

(Special effect) The present invention has the following unique effects.

The temperature reference value for opening and closing the exhaust valve does not have to be entered manually; it is automatically converted into temperature from the pressure sensor value and entered, so the operation is very simple and there are no input errors. .

In a mixture of steam and air, when the mixing ratio of air is low, air has a lower density than steam, so it separates and collects at the top. In the present invention, the valve responds sharply to temperature changes in the steam space, and opens and closes the valve at a temperature close to the saturation temperature, that is, when the air mixing ratio is small. can be discharged, and there is little steam outflow.

Also, since the steam space is maintained at a low air mixing ratio, the temperature drop is small. Since the efficiency of the heater depends on the temperature difference between the steam space and the material, this heating efficiency is increased.

(Example) A specific example of the present invention will be described below (see FIG. 1).

The steam heating device 1 is a hollow vessel with a material inlet pipe 7 and a product outlet pipe 8 attached to the side walls. Both tubes 7, 8 are connected to a heating tube 17 located in the steam space 2 in the vessel of the heating device 1.

A steam supply pipe 3 is connected to the upper part of the steam space 2. A pressure reducing valve 4 is attached to the supply pipe 3. Valves are installed before and after the pressure reducing valve 4 and in a bypass pipe parallel to the pressure reducing valve 4.

A condensate discharge pipe 5 is connected to the lower part of the steam space 2. A steam trap 6 is attached to the discharge pipe 5, and valves are attached to the front and rear of this and to the bypass pipe parallel to this.

An exhaust pipe 9 is connected to the upper part of the steam space 2 and an exhaust valve 11 is arranged. A valve actuator 10 is attached to the exhaust valve 11 to drive the valve using an external force such as electricity or fluid pressure.

Electric temperature sensor 1 at the top of the steam space 2
4 and pressure sensor 15 are attached. Both sensors 14, 15 are connected to the controller 12 by signal lines. The controller 12 has a built-in microcomputer, and its storage means stores the steam pressure and a temperature slightly lower than the saturation temperature for that pressure. Therefore, when a signal from the pressure sensor 15 enters the controller 12, the temperature corresponding to the pressure is calculated from the stored relationship between the steam pressure and the corresponding temperature, and this is used as the reference temperature.

The controller 12 also includes a comparator that compares the signal from the temperature sensor 14 with the reference temperature and outputs an instruction signal to the valve actuator. That is, a signal from the temperature sensor 14 is sent to the controller, which controls the valve actuator to open the exhaust valve 11 if the temperature of the steam space 2 is lower than the reference temperature, and to close it if it is higher.

Since the storage means of the controller 12 stores the relationship between steam pressure and a temperature slightly lower than the saturated temperature corresponding to the pressure, saturated steam can be discharged when the exhaust valve 11 opens to discharge the fluid. The economic effect is also large.

In the above embodiment, the reference temperature is converted into temperature and automatically inputted from the pressure sensor 15.
Alternatively, a reference value setter 13 may be provided that allows any reference temperature to be input manually.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of piping in which an exhaust system according to an embodiment of the present invention is attached to a steam heating device, and FIG. 2 is a schematic diagram of conventional piping corresponding to FIG. 1. 1: Steam heating equipment, 2: Steam space, 3: Steam supply pipe, 5: Condensate discharge pipe, 9: Exhaust pipe, 10:
Valve actuator, 11: exhaust valve, 12: controller, 13: reference value setter, 14: electrical temperature sensor, 15: pressure sensor, 51: exhaust valve that thermostatically operates by itself.

Claims (1)

[Claims] 1 Attach an electric sensor to detect the temperature of the steam space and an electric sensor to detect the pressure to the steam heating equipment, and place an exhaust valve driven by a valve actuator in the passage that exhausts the air accumulated in the steam heating equipment. , a controller is arranged that stores the relationship between steam pressure and a temperature slightly lower than the saturation temperature, and the pressure is automatically converted into a corresponding temperature within the controller according to a signal from the pressure sensor. The temperature is set as a reference value, and the valve actuator is controlled so that the signal from the temperature sensor approaches the reference value determined in the controller, and the exhaust valve is opened when the steam space is below the reference value. Device.