JPH05141615A - Controlling device for quality of steam - Google Patents

Abstract

PURPOSE:To so control as to become desired wetness or dryness fraction by detecting the wetness fraction of steam to be supplied to a steam using device. CONSTITUTION:Steam wetness fraction detecting means 2 is disposed at an inlet side of a steam using device 1. The means 2 is connected to a controller 3. A coolant pouring valve 4, a pressure regulating valve 5 and a heater 7 are provided at a primary side of the means 2, and connected to the controller 3. The wetness fraction of the steam to be supplied to the device 1 is detected by the means 2, and a valve, the heater 7 are so controlled as to become a desired wetness fraction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam quality control device for controlling the wetness or dryness of steam supplied to a steam using device used in various factories and production plants.

Steam is often used as a heat source or a driving source for production in factories and plants. Steam is usually generated in a boiler and sent to each steam using device through a pipe.
There are various steam pressures used in the steam-using device, and the steam is generated at the highest pressure in the boiler, and the steam is depressurized at each point of use and used as the steam at the desired pressure, that is, the temperature. By decompressing steam normally,
When the amount of heat released is relatively small, the temperature is not so much decreased even if the pressure is decreased, which is so-called superheated steam. Since the superheated steam has a temperature higher than the saturation temperature of the steam at that pressure, the superheated steam is cooled to have the saturation temperature in consideration of heat resistance and temperature controllability.

[0003]

2. Description of the Related Art As a conventional temperature reducing device, for example, Japanese Patent Publication No.
There is one disclosed in Japanese Patent No. 14682. It consists of a control valve that controls the flow rate of steam and a desuperheater that injects cooling water into the steam. Even if the flow rate of steam changes from low to full flow, vibration and It effectively reduces the pressure and temperature of steam without generating noise.

[0004]

In the above conventional temperature reducer, the steam can be efficiently depressurized and reduced in temperature, but there is a problem that the wetness or dryness of the steam cannot be maintained at a desired value. It was That is, although cooling water can be injected by a superheater to reduce the temperature of steam, it is also possible to detect the degree of wetness and dryness of the reduced temperature steam, and also to detect the degree of wetness and dryness. It cannot be adjusted. The wetness of steam is the mass of the liquid contained in 1 kilogram of wet saturated steam, and when the wetness is high, the amount of water droplets contained in the steam increases. If water vapor is contained in the steam, it will not be possible to heat the object to be heated uniformly, water damage will occur in the case of food or chemicals, and steam-using equipment will be rusted or corroded. An increase in the amount may cause a water hammer phenomenon and damage the device. On the other hand, in the case of heating some fibers or chemical products, if the wetness becomes too low, that is, if the dryness becomes too high, the target product may cause heat damage such as burning, and steam. The wetness of the must be tightly controlled.

Therefore, a technical problem of the present invention is to make it possible to control the quality of steam by accurately adjusting the wetness or dryness of steam.

[0006]

The structure of the steam quality control device of the present invention is as follows. The wetness detecting means for detecting the wetness or dryness of the steam is arranged on the inlet side of the steam using device, and the detection signal from the wetness detecting means is inputted to the steam provided on the primary side of the wetness detecting means. A controller for emitting a drive signal for driving a valve for decompressing or injecting cooling water, a heat exchanger for heat exchange of steam, and the like is provided.

[0007]

By arranging the wetness detecting means on the inlet side of the steam using apparatus, the wetness or dryness of the steam supplied to the steam using apparatus can be detected. The signal of the wetness or dryness of the steam detected by the wetness detecting means is input to the controller. The desired wetness or dryness is compared with the wetness or dryness detected by the controller,
A drive signal for driving the steam pressure reducing valve, the cooling water injection valve, the steam heat exchanger, etc. provided on the primary side of the wetness detecting means is output so that the deviation between the two becomes zero, and is supplied to the steam using device. The wetness or dryness of the vapors produced is controlled.

The high-pressure steam delivered from the boiler is usually 1
It has a wetness of some, typically a few percent, rather than 00 percent dry steam. The steam is depressurized by passing the steam through a throttle such as a valve.
When the depressurization is performed as an isothermal change, the water droplets of several percent contained in the steam before the depressurization are re-evaporated according to the degree of the depressurization, so that the wetness of the steam decreases and the dryness increases. The superheat degree is reduced by injecting the cooling water into the superheated steam, and the wetness degree is increased by injecting the cooling water into the dry saturated steam. Further, by heating the wet saturated steam, the wetness is decreased and the dryness is increased, and by heating the dry saturated steam, the superheat is increased. In this way, by depressurizing the steam, injecting cooling water, and exchanging heat, the wetness or dryness of the steam and also the superheat can be adjusted.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The illustrated embodiment will be described in detail. First embodiment (see FIGS. 1 to 4). A steam using device 1, a wetness detecting means 2 arranged on the inlet side of the device 1, a controller 3, a cooling water injection valve 4 and a pressure control valve 5 driven by a signal from the controller 3,
A steam quality control device is formed with the heater 7 that reheats the steam from the boiler 6. A boiler fuel supply valve 8 for supplying fuel and a water supply valve 9 for supplying water are connected to the boiler 6. An automatic opening / closing valve 10 is attached near the entrance of the steam using device 1. Reference numeral 11 is a detector for detecting the pressure and temperature of the steam, and reference numeral 12 is a steam trap for discharging the condensate drained by the steam using apparatus 1.

A concrete structure of the wetness detecting means 2 is shown in FIGS. 2 to 4. FIG. 2 shows a so-called throttling-type steam wetness detection device that utilizes isenthalpic change of steam. The pressure reducing valve 22, the heat receiving or radiating means 23, the measuring section 24 and the extraction pump 25 are sequentially connected to the steam pipe 20 to be measured through the introduction passage 21, and the temperature sensor 26 is attached to the measuring section 24 to receive the heat receiving or radiating means. A heat quantity display unit 27 for calculating and displaying heat received / heat radiation quantity is attached to 23, and a pressure sensor-2 is attached to the steam pipe 20.
8 is attached. The wet steam to be measured is throttled by the pressure reducing valve 22, superheated in the measurement unit 24, and the wetness of the steam is calculated using each temperature and pressure and the Mollier diagram or the saturated steam table or the superheated steam table. It is a thing. The measurement unit 24 is put into a low pressure state by the extraction pump 25 so that even steam having a relatively high degree of wetness can be superheated to vaporize,
The wettability can be calculated.
Further, the heat receiving / radiating means 23 can convert the steam having a higher degree of wetness into a saturated vapor by supplying a predetermined amount of heat, and the degree of wetness can be measured. By consuming it, saturated liquefaction can be performed and the degree of wetness can be measured.

FIGS. 3 and 4 show a wetness detecting means 2 for vapor utilizing the fact that infrared rays of a predetermined wavelength are absorbed by water droplets by using a pyroelectric element. In FIG.
An optical fiber 30 for receiving infrared rays in the vapor pipe 20
And attach the other end of the optical fiber-30 to the wetness measuring unit 3
It is connected to 1. The wetness measuring section 31 is provided with a pyroelectric element 32 and a rotary plate 34 rotated by a motor 33. The rotary plate 34 is arranged on the axis connecting the other end of the optical fiber 30 and the pyroelectric element 32, and has a rotary surface that rotates in a plane orthogonal to this axis, and this rotary surface is as shown in FIG. , Through holes 3 provided at equal intervals and in different numbers
5 and a filter lens 36 that passes only wavelengths that are absorbed by water droplets, for example, near infrared rays of 1.9 micrometer. An amplifier circuit 37, a filter circuit 38, a rectifier circuit 39, an A / D converter 40, a CPU 41, and a wetness degree display unit 42 are sequentially connected to the pyroelectric element 32 in FIG.

The wetness detecting means 2 utilizes that all of them having a calorific value emit infrared rays, and that infrared rays having a wavelength of about 1.9 micrometer are very well absorbed by water droplets. The wettability is measured by changing the amount of infrared rays absorbed depending on the amount of water droplets in the steam pipe 20.

As the detecting means other than the wetness detecting means shown in FIGS. 2 to 4 described above, for example, a plurality of thin electrodes are arranged so as to face each other. If so, it is possible to detect the approximate degree of wetness by not conducting electricity.

The cooling water injection valve 4 in FIG. 1 communicates with the lower end of the pressure control valve 5 so that cooling water can be injected into the steam in the control valve 5. The heater 7 heats the steam by the combustion exhaust gas of the boiler 6, and is capable of supplying a predetermined amount of heat to the steam by adjusting the amount of the exhaust gas that exchanges heat with the steam (not shown). Although not shown in the controller 3, a setting unit for setting a desired wetness or dryness of steam and a set value from the setting unit and a detected value from the wetness detecting means 2 are compared. Comparing section, computing section for computing the opening degree of each valve required for zeroing the deviation between the two and the amount of exhaust gas required in the heating section 7, and the result of the computation for each actuator section And a display unit for displaying the detection result, the comparison result, the calculation result, and the like.

Next, the operation will be described. The wetness or dryness of the steam supplied to the steam using apparatus 1 is detected by the wetness detecting means 2. If the degree of wetness required by the steam using device 1 set in the controller 3 differs from the above-mentioned detected value, the cooling water injection valve 4, the pressure control valve 5 and the heater 7 should be eliminated so as to eliminate the difference. Alternatively, the fuel supply valve 8, the water supply valve 9, the automatic opening / closing valve 10, etc. are driven, and the steam using device 1
The degree of wetness of the steam supplied to is maintained at a desired value.

By controlling the respective valves and heaters based on the detected values of the pressure and temperature by the detector 11,
It is possible to control not only the wetness of the supply steam but also the superheat.

Second embodiment (see FIGS. 5 and 6). In this embodiment, as the wetness detecting means 2, the diaphragm-type wetness detecting means described in the first embodiment is used, and instead of the heater 7 in the first embodiment, heating and injection of cooling water can be performed simultaneously. An example using the heating / cooling device 50 is shown. A steam pipe 51 is provided with an automatic setting pressure reducing valve 54, which is a combination of a motor 52 as a drive unit and a steam trap 53, and a heating / cooling device 50, a pressure / temperature detector 11 and a wetness detection device on the secondary side. The means 2 and the steam using device 1 are connected in series.

As shown in FIG. 6, the heating / cooling device 50 has a casing 55 which forms an inlet 56, a gas-liquid separator 57 and an outlet 58. The gas-liquid separating section 57 has double cylindrical members 59 and 60 arranged therein, and an annular space 61 formed by the cylindrical members 59 and 60.
Through the screen 62 to communicate with the inlet 56. A swirl vane 63 that swirls the fluid from the inlet 56 is provided in the annular space 61, and the lower end of the inner cylindrical member 60 is formed into a skirt-like shape to form a draining portion 65. Inner cylindrical member 60
A coiled pipe 66 as a heater is attached inside the. A heat medium supply port 67 is provided at the upper end of the pipe 66 and is connected to the heat medium supply pipe 68. A heat medium discharge port 69 is also provided at the lower end of the pipe 66, and is connected to the discharge pipe 70. The pipe 66 is formed in a coil shape whose diameter is sequentially different so that the vapor reaching the outlet 58 is more likely to come into contact with the pipe 66.

A cooling water injection nozzle 71 is attached between the inlet 56 and the swirl vane 63, and is connected to the cooling water pipe 72 via the cooling water injection valve 4. In this embodiment, the injection nozzle 7
Although one provided with one is shown, a plurality of may be provided. Further, the injection nozzle 71 preferably has a nozzle shape capable of injecting cooling water in a spray state.

A liquid reservoir 73 is communicated below the water draining portion 65, and a float valve 74 inside is arranged in a free state. A valve seat member 76 that penetrates the valve port 75 at the bottom of the float valve 74.
Attach. The valve port 75 communicates with the outside of the system through the liquid discharge hole 77. A float cover 78 for preventing the swing of the float valve 74 is provided on the outer periphery of the float valve 74, and a through hole 79 is provided at the upper portion of the float cover 78.

An automatic setting pressure reducing valve 81 having a motor 80 corresponding to the pressure reducing valve 22 in FIG. 2 is provided on the inlet side of the wetness detecting means 2, and an bleeding pump is provided on the outlet side via an automatic three-way valve 82. The ejector type combination pump 83 is connected. The combination pump 83 includes an ejector 84 and a tank 8.
5 and a spiral pump 86, the circulating pump 86 causes the circulating water in the tank 85 to pass through the ejector 84 to generate a suction action, thereby maintaining the inside of the wetness detecting means 2 at a predetermined low pressure. .. A tank water cooling valve 87 is attached to the tank 85 to supply cooling water. Further, a surplus water discharge valve 88 is provided between the spiral pump 86 and the ejector 84.
Attach.

A steam trap 12 and an automatic three-way valve 90 are attached to the outlet side of the steam using apparatus 1. Automatic three-way valve 9
One outlet of 0 is communicated with the ejector 84 portion of the combination pump 83 via the pipe 91. By operating the automatic three-way valve 90, the condensate discharged from the steam trap 12 is discharged to the outside of the system, or the combined pump 83 sucks the condensed water, so that the inside of the steam using device 1 is in a low pressure state including atmospheric pressure or less. Can be maintained at.

Next, the operation will be described. The wetness of the steam supplied to the steam using apparatus 1 is detected by the wetness detecting means 2, and is compared with the set wetness by a controller (not shown) to be calculated, and the respective valves and the heating / cooling device 50 are operated. , Controlled to the desired wetness. In the heating / cooling device 50, the steam flowing in from the inlet 56 is mixed with the cooling water from the cooling water injecting nozzle 71, passes through the screen 62, and reaches the gas-liquid separation section 57. Swirl vanes 63 in the annular space 61
As a result, the mixed fluid of steam and cooling water is swirled, cooling water with a large mass is swung outward by centrifugal force, and steam with a small mass swirls inside the annular space 61 to separate gas-liquid. The vapor from which the liquid has been separated is drained by the drainer 6
From the lower end of 5 to the inner circumference of the inner cylindrical member 60. By flowing down a predetermined heat medium in the pipe 66 as a heater, the steam can be adjusted to a desired temperature. The temperature-adjusted steam flows down from the outlet 58 to the pressure / temperature detector 11.

The liquid swirled to the outside in the heating / cooling device 50 travels along the inner wall of the casing and flows down and is stored in the liquid storage chamber 73. When a predetermined amount of liquid is collected, the float valve 74 floats by buoyancy and opens the valve port 75, so that the liquid is removed from the system.

In the present embodiment, an example is shown in which cooling water is injected to reduce the temperature of the steam to increase the wetness, and an indirect heat exchanger is used to heat the steam to increase the dryness. However, in either case, the quality of the steam can be controlled by direct or indirect heat exchange. Further, in the present embodiment, only the example in which the pressure of the steam is reduced is shown, but it is also possible to increase the wetness and the dryness by increasing the pressure by using a compressor or the like.

[0026]

According to the present invention, the wetness of the steam supplied to the steam using apparatus is detected, and the steam is depressurized, cooling water is injected, or heat is applied so that the desired wetness or dryness can be obtained. By replacing it, the wetness of the supply steam can be adjusted with high accuracy, and it is possible to prevent uneven heating of the heated object, rust and corrosion, and damage to the product and steam-using device. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a steam quality control device of the present invention.

FIG. 2 is a configuration diagram showing a wetness degree detecting means used in the vapor quality control device of the present invention.

FIG. 3 is a configuration diagram showing another wetness degree detecting means used in the vapor quality control device of the present invention.

FIG. 4 is a side view of a rotary plate of the wetness degree detecting means in FIG.

FIG. 5 is a configuration diagram showing another embodiment of the steam quality control device of the present invention.

6 is a cross-sectional view of the heating / cooling device in FIG.

[Explanation of symbols]

 1 Steam use device 2 Wetness detection means 3 Controller 4 Cooling water injection valve 5 Pressure control valve 6 Boiler 7 Heater 50 Heating / cooling device 54 Automatic setting pressure reducing valve 82 Automatic three-way valve 84 Ejector

Claims (1)

[Claims] 1. A wetness detecting means for detecting the wetness or dryness of steam is disposed on the inlet side of the steam using device, and a detection signal from the wetness detecting means is inputted to the primary means of the wetness detecting means. A steam quality control device equipped with a controller that issues drive signals for driving valves and heat exchangers installed on the side.