JPH061185B2 - Method and apparatus for detecting state of adhered matter in fluid pipe - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for easily and surely detecting an adhesion state such as a thickness of an adhered matter adhered in a pipe through which a fluid flows.

BACKGROUND ART Adhesive matter adheres to pipes of heat exchangers in which cooling water or steam flows, pipes for transportation of slurries, seawater, etc.
As a result, heat exchange performance or fluid transport efficiency is reduced.

Taking a heat exchanger as an example, as symbolized by thermal power generation,
In order to increase the power generation efficiency, it is necessary to increase the temperature difference between the high temperature heat source and the low temperature heat source in the power generation (Rankin) cycle. A heat exchanger is used to keep the temperature of the low temperature heat source lower, and cooling water (for example, seawater) is made to flow at a constant flow rate in a large number of the pipes. However, since the microorganisms and bacteria are present in the cooling water and adhere to the inside of the pipe, the heat transfer efficiency is deteriorated.
Although barnacles and bacteria adhere to the inner wall of the tube are called slime, at present, it is assumed that this slime or a scale of minerals adheres to the inner wall of the tube with a thickness of several tens of μm to several mm for several days to several tens of days. A solid body such as a plastic sponge ball is periodically flown into a pipe of a heat exchanger or the like every other day to remove the deposits on the inner wall of the pipe. Conventionally, in order to detect the adhesion state of the adhered matter, a pressure sensor is arranged in a part of a large number of tubes, and the adhesion state is investigated by changing the water pressure when the adhesion layer becomes thick.

Problems of the prior art By the way, when slime or scale adheres to the inner wall of the pipe, the pressure loss increases, but it is difficult to detect the change in water pressure due to this and reliably grasp the adhered state of the adhered matter. The device is also expensive.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has an object to provide a method and apparatus for easily and reliably detecting the condition of an adhered substance adhering to the inside of a pipe, and one of the detecting methods. The gist of is to apply a constant amount of heat to the outer circumference of the pipe through which the fluid flows per unit time, and measure the temperature change of the outer wall of the pipe or the change of the heat flow caused by the deposits adhering to the inside of the pipe.

Further, the gist of another one of the detection methods is to monitor the temperature of the pipe so as to give a variable amount of heat to the outer periphery of the pipe through which the fluid flows so as not to change the temperature change of the outer wall of the pipe caused by the deposit inside the pipe. To supply the variable heat quantity and measure the heat quantity or heat flow.

On the other hand, the gist of one of the detection devices is a heater provided in a predetermined range on the outer circumference of a pipe through which a fluid flows to give a constant amount of heat to the outer circumference of the pipe in a unit time, and at least a pipe provided with the heater. It is provided with one or more thermometers which are provided in the outer peripheral portion and measure changes in the outer wall temperature of the tube.

Further, the gist of another one of the detecting devices is that a heater is provided in a predetermined range on the outer circumference of a pipe through which a fluid flows, and a heater for providing a constant amount of heat per unit time to the outer circumference of the pipe, and at least the heater is provided. It is provided with one or more heat flow meters which are provided on the outer peripheral side of the tube and measure changes in heat flow of the outer wall of the tube.

Further, the gist of another one of the detection devices is a heater provided in a predetermined range on the outer circumference of a pipe through which a fluid flows to give a variable amount of heat to the outer circumference of the pipe, and at least an outer circumference of the pipe provided with the heater. One or more thermometers for measuring the temperature of the outer wall of the pipe, and the temperature of the outer wall of the pipe to prevent the temperature change of the outer wall of the pipe due to the deposits in the pipe. That is, it is provided with a power source for changing the amount of heat variable to the tube by the heater and a measuring device for measuring the amount of electric power supplied to the heater.

Detailed Description of the Invention FIGS. 1 (a) and 1 (b) show an example of a model for explaining the present invention. In the figure, reference numeral 1 indicates the length of the pipe 2: the entire circumference of the l part. The heater A is provided along the heater 1, and the heater 1 and a thermometer and a heat flow meter described later constitute a sensor A. For the time being, heat conduction from the heater into the wall of the pipe 2 is one-dimensional.

If the heat flux due to the heat generated by the heater 1 is uniform over time, the surface temperature of the wall surface deposit 3 in the pipe 2 should change along the flowing direction of the fluid 4 in the pipe 2, but here Since the purpose is to grasp the basic characteristics for detection of the deposit 3, it is assumed that the center (l / 2 position) P of the heater 1 can be used for one-dimensional heat transfer, and the deposit 3 has a uniform thickness δ. It is analyzed that it is attached to the inner wall of the pipe.

When the heat flow flowing to the pipe 2 side out of the total heat quantity Q generated by the heater 1 is Q _i , the heat conduction in the pipe 2 is given by the following equation.

However, T _o : temperature of the outer wall of the pipe T _i : temperature of the inner wall of the pipe λ: thermal conductivity of the pipe material γ _o : outer radius of the pipe γ _i : inner radius of the pipe Further, the heat conduction in the deposit 3 is as follows. .

Where T _{s is} the temperature of the fluid-side surface of the deposit, λ _s is the thermal conductivity of the deposit, γ _{s is} the radius to the inner surface of the deposit, and the heat transfer state from the surface of the deposit to the fluid is given by the following equation. .

Where T _{f is} the temperature of the fluid flowing through the center of the pipe α is the heat transfer coefficient (1), (2), (3) On the other hand, when the outer periphery of the pipe 2 is covered with the heat insulating material 5, the amount of heat Q _o escaping to the outside through the heat insulating material 5 is given by the following equation.

However, T _∝ : outside temperature h: heat transfer coefficient from heat insulating material surface λ _a : heat conductivity of heat insulating material γ _a : outer surface radius of heat insulating material Heat generation amount (heat flow) Q from heater 1 is Q = Q _i + Q _o ………… (6) In correspondence with Eqs. (4) and (5), if the heat insulation performance of the heat insulating material 5 is improved, the value of Q _o will be extremely small and can be regarded as almost constant. Therefore, it can be considered that the heat generation amount Q of the heater 1 and the heat flow Q _i flowing into the pipe 2 are in a proportional relationship. If the heat transfer coefficient h from the outside of the heat insulating material 5 hardly changes,
Even if the heat insulating material 5 is not used, if Q is kept constant, the change of the heat flow Q _i flowing into the pipe 2 is Q _o =
Q-Q _i enables detection as a change in Q _o flowing to the outside world.

Further, _assuming that the outer peripheral temperature of the pipe 2 when the deposit 3 is not attached is T _o ′, by setting γ _s = γ _{i in the} equation (4), From equation (4) and equation (7) Is obtained.

Considering that the presence of the deposit 3 is detected when the thickness δ of the deposit 3 is sufficiently smaller than γ _i , γ _s = γ _i −δ ………… (9) , And obtain the following equation as a good approximation.

According to the equations (10) and (11), if the amount of heat generated from the heater is kept constant per unit time, the temperature difference (T _o −T _o ′) becomes large in proportion to the thickness δ of the deposit 3. Become. Alternatively, if the flow velocity of the fluid 4 in the pipe 2 decreases as the thickness δ of the deposit 3 gradually increases, the thermal conductivity α becomes small, and therefore (1 / λ _s + 1 / αγ _{Since i} ) is a value that increases, the value of (T _o −T _o ′) is also large. That is, as the thickness δ of the deposit 3 increases, the value of the temperature difference (T ₀ −T _o ′) also tends to increase accordingly. Detect (T _o −
Knowing from T o _') is extremely effective in evaluating the heat transfer efficiency.

Further, the temperature T _{f of the} fluid 4 flowing in the pipe 2 is determined by the heater 1
The temperature of the outer wall of the pipe 2 at a point that is not sufficiently affected by the temperature rise due to the heating of the heater 1 (especially on the upstream side with respect to the flow, the point is a point close to the heater 1,
On the downstream side, as soon as the influence of heating by the heater 1 disappears, a good approximation can be obtained, that is, a point far away from the heater 1) T _f ′, and T _f = T _f ′, and the temperature T _f ′ at this point and the heater 1 are constant. The adhered state of the adhered matter can also be detected by obtaining the temperature difference with the temperature T _o of the outer wall of the pipe 2 on the lower surface of the heater 1 when the heat is generated (hereinafter, T _f ′ is T _f
Note).

On the other hand, if it is attempted to detect a place where the deposit 3 has a certain thickness, the temperature difference (T _o −
(T _o ′) or the value of (T _o −T _f ) in the equation (4) is fixed at a fixed value, and the heat flow Q _i per unit time that should be the value is considered.
It is possible to know that the deposit 3 has adhered to a certain thickness by obtaining the value of from the heat flow meter or the amount of electric power applied to the heater 1 per unit time. That is, the value of Q _i gradually decreases as the thickness δ of the deposit 3 increases, and when it reaches a certain value, it is detected that the deposit 3 has adhered to an allowable thickness. .

As described above, the thickness of the deposit 3 depends on the calorific value Q of the heater 1.
Is constant, the temperature difference (T _o −T _o ′) and the temperature difference (T _o
-T _f ) and the heat flow Q _i and the heat flow Q _o ,
Further, the temperature difference (T _o −T _o ′) or (T _o −T _f ).
The temperature of the tube is monitored in consideration of detection as a constant value, and the value of the heat input to the heater or the heat flow, which is the constant value, is detected.

The above description has been made on the sensor A in which the heater 1 surrounding the entire circumference of the pipe 2 is provided. However, as shown in the sectional view of FIG. It is known that the above-described two detection methods can be easily performed by the same analysis even for the sensor A that is present in a part thereof and generates heat.

When the device including the power source of the sensor and the detection circuit is attached to, for example, a heat exchanger, it is as shown in FIG.
That is, the pipe 2 is several hundreds to two with one heat exchanger.
The number of pipes is extremely large, about 0000, and the cooling water flows in these pipes at a substantially constant flow velocity. Microorganisms and mineral components contained in this cooling water adhere to the inner wall of each pipe, reducing heat transfer efficiency. In the above pipe, "heater and one or more thermometers and heat insulating materials", "heater and one or more thermometers", "heater and heat flow meter and thermometers and heat insulating materials", and further "heater and A sensor such as a "heat flow meter" is attached to several to several tens of appropriately selected pipes of the heat exchanger. In the figure, the sensor 11 is directly attached to the pipe 2,
The sensor 12 is made of the same material as the pipe 2, has the same dimensions, and has a length of several cm.
A dummy pipe 13 of several tens of cm is added to a cooling pipe, and a sensor is arranged on the dummy pipe 13. The lead wires 14 of the sensors 11 and 12 are taken out through a hatch 15. The sensors 11 and 12 may be those in which the heater shown in FIG. 1 is present on the entire circumference, or those mounted on a part of the outer circumference of the pipe as shown in FIG.

Specific Configuration and Operation of Device According to the Present Invention Next, the configuration is shown in FIGS. 4 (a) (b) to 13 by taking a sensor having a full-circumferential heater as an example. There are two types of these sensors, one having a dummy pipe as a constituent of the sensor and the other not having the dummy pipe for mounting on the actual pipe. As the thermometer used for these, a thermometer used for normal temperature measurement such as a thermocouple, a thermistor, or a thin temperature measuring resistance element is used. A thin or sheet resistance temperature element can obtain an average outer wall temperature, and a thermocouple or a thermistor can obtain a temperature of one point. It goes without saying that the outer wall temperature may be measured. Also, the heat insulating material that covers the outside of the heater is arranged so as not to be affected by thermal fluctuations on the external side, but the heat on the external side due to changes in temperature or changes in heat transfer coefficient, etc. It is not necessary to use it when there is almost no fluctuation. When using a heat flow meter,
In order to increase the output signal, a structural material (a material with low thermal resistance) may be used instead of the heat insulating material.

4 (a) and 4 (b) are a sensor including a heater 1 surrounding the pipe 2, a thermometer 16 for detecting the temperature of the outer wall of the pipe in the area where the heater 1 exists, and a heat insulating material 5 surrounding the heater 1. Is. In this case, as described above, a plurality of thermometers are used to measure the average temperature, and when the thermal fluctuation on the outside is small, the heat insulating material 5 may not be provided. Further, it is also possible to measure the temperature from the action of causing heat to be generated by using, for example, a platinum resistance temperature measuring element as the heater 1 and the resistance value of the heater 1 at that time. That is, the heater also serves as the temperature measuring element. In the case of platinum, the temperature coefficient of its resistance is 1
It is about 3800ppm per ° C, and the resistance value changes only a little less than 4% even if the temperature rises by about 10 ° C. Therefore, when the platinum resistance element is heated by applying a constant current or applying a constant voltage, the amount of heat generated Can be regarded as almost constant. On the other hand, a resistance value change of less than 4% is in the field of temperature measurement technology.
It can be easily detected, and using this simplifies the structure of the sensor.

FIGS. 5 (a) and 5 (b) show an example of the structure of a sensor which is actually attached to the pipe 2 without using the dummy pipe 13, and is divided into two parts which are attached to the outer periphery of the pipe 2. is there. In this case, the heater 1 is arranged in a hairpin shape as shown in FIG. 5 (b). As a matter of course, the sensor described below can also have a two-part structure as required.

FIG. 6 shows a sensor in which a thermometer 16 ′ for measuring the outer peripheral temperature T _f ′ (T _f ) of the pipe 2 at a point distant from the heater 1 is added to FIG. , According to the equation (4), the outer wall temperature of the pipe in the area where the heater exists and the temperature at the point away from the heater are respectively measured and the difference between the two is taken, or a differential connection circuit (for example, a thermocouple is The temperature difference is simultaneously obtained by thermocouple connection or differential thermocouple group connection).

FIG. 7 shows a sensor using a heat flow meter 17 in place of the thermometer 16 of the sensor shown in FIG. 4. Even if the heat flow meter 17 is arranged between the heater 1 and the pipe 2, the heat flow meter is placed outside the heater 1. 17 'may be arranged. In this sensor, it is not preferable to use the heat insulating material 5 that covers the outside as described above, especially when the heat flow meter is arranged outside because the change response amount of the output signal of the heat flow meter 17 'becomes small. Therefore, the structural material 18 that supports the structure of the sensor and is made of a material having a low thermal resistance is used.
Is used instead of the heat insulating material 5.

The above-mentioned sensor has described the configuration of the sensor that detects the temperature difference and the heat flow while keeping the heat generation amount of the heater constant per unit time. Next, the configuration of the sensor that detects the increase and decrease of the heat generation amount while keeping the temperature difference and the heat flow constant. Indicates. These sensors are (10)
Equation (11) (T _o −T _o ′) is a constant value, and when the calorific value is changed so as to obtain the temperature difference, the amount is to be detected from the heat flow meter or the input electric energy. is there.

FIG. 8 shows the heater 1 and the pipe 2 in the range where the heater exists.
It is a sensor consisting of a thermometer 16 for measuring the outer wall temperature and a heat flow meter 17 'arranged outside the heater. For the above-mentioned reason, the material covering the outside is preferably the structural material 18 rather than the heat insulating material.

FIG. 9 shows the heat flow meter shown in FIG. 8 provided inside the heater 1. In this case, the outside may be covered with the structural material 18, but if there is a possibility that thermal fluctuations may occur on the external side, it is better to use the heat insulating material 5.

FIG. 10 shows a change in the amount of heat generated in FIG. 4 detected by the meter 19 for the amount of electric power, voltage or current supplied to the heater 1.

Further, the sensors shown in FIGS. 11, 12, and 13 are
As shown in the sensor of FIG. 4 with the addition of a thermometer 16 ', the temperature of the outer wall of the pipe at the point distant from the heater is different from that of the sensor of FIGS. 8 and 9, respectively. A thermometer 16 'for measuring is added.

Next, a method for determining the thickness of the deposit 3 using the above sensor,
The device will be described.

For the sensor A using the thermometer of FIGS. 4 (a) and 4 (b),
As shown in FIG. 14 (a), a constant current or voltage 22 is pulsed from the power source 21 to the heater 1 of the sensor A for several tens of seconds to several minutes or continuously to generate heat. The pulse heating time may be the time until the temperature rise due to heating reaches a certain value, and depends on the material of pipe 2, size and the like. If the temperature of the cooling water or the water to be cooled does not change, pulse heating or continuous heating may be used. However, if it fluctuates, pulse heating is used. By doing so, only the temperature rise due to heating is detected by the thermometer, and reliable data can be obtained.

In order to obtain the temperature difference (T _o −T _o ′), a constant amount of heat generation is generated from the heater 1 per unit time, and the temperature T _o ′ in the initial state without the deposit 3 is obtained. Thereafter, if measured by the temperature measuring device 19 indicating the temperature _{T o} which over time to increase in FIG. 14 _{(a) (T o -T o} ') is obtained. Further, as shown in FIG. 6, the center temperature of the fluid (the same as the outer wall temperature T _f ′ of the pipe 1 sufficiently separated from the heater 1) T
_{If f} is measured, (T _o −T _f ) can be obtained.

This constant heat generation method is the heat flow meter 17 or 1 shown in FIG.
The same applies to the sensor using 7 ', and since the adhered matter adheres to the pipe 2, the heat flow flowing to the pipe 2 side decreases due to constant heating, and the heat flow flowing to the outside increases by that amount.
As shown in the figure, this heat flow is detected by the heat flow meter 17 or 17 ', and is measured by the heat flow measuring device 20 as shown in FIG. 14 (b).

Further, in the sensors of FIGS. 8, 9 and 10,
It is the same as making the heater 1 generate heat in a pulsed or continuous manner, but assuming that the temperature difference of (T _o −T _o ′) is, for example, 5 ° C., the difference is as shown in FIG. 14 (c). The amount of electric power supplied to the heater 1 at which the temperature becomes 5 ° C. is measured by the measuring device 23 or the heat flow value is measured by the measuring device 20 to know the adhesion state of the adhered matter.

Further, in FIG. 11, FIG. 12 and FIG. 13, similarly, the temperature of the tube is monitored so that the temperature difference (T _o −T _f ) is a constant value, and the electric power supplied to the heater is changed. . In this case, in any of the sensors, the heat flow measuring element or the thermometer is more than the constant heat generation method, which leads to an increase in cost, and the amount of electric power supplied to the heater is extremely large when there is no attached matter, Although the adjustment of heating in the detection is troublesome, it can be effectively used when the adhesion gradually increases from a slightly adhered state.

Next, as an example of the case where the deposit 3 is attached to the pipe 2,
The results obtained by numerical calculation of the relationship between the temperature difference (T _o −T _o ′) and the thickness δ of the deposit 3 and the application method to the actual deposit will be described.

The heat transfer tube is made of aluminum brass with an outer diameter of 25.4 mm, an inner diameter of 22.91 mm, a thermal conductivity of 100 W / (m · k), and water flows in the tube at an average velocity of 2 m / sec. The water temperature was set to 15 ° C. Further, the length of the heater 1 is 20:
mm, the entire circumference of the pipe 2 was surrounded, and Q _{i was} 53.4 W. Outside the heater 1, the thermal conductivity: 0.06 W /
(M.k) heat insulating material 5 is provided with a thickness of 10 mm, and the heat transfer coefficient to the outside is h: 20 W / (m.k), T∝: 1.
The temperature was 5 ° C.

Since it is extremely difficult to obtain the thermal conductivity of the deposit 3, when the heat insulating material is equivalent to 0.08 W / (m.k), when it is close to ceramics: 23 W / (m · k) and its It was calculated by assuming three thermal conductivities of an intermediate value: 0.587 W / (m · k). It is considered that the thermal conductivity of the deposit 3 is at least in the range of 0.08 to 2.3 W / (m · k). The calculation result is shown in FIG.

At λ _s : 0.08 W / (m · k), the thickness of the deposit 3 is 2
When it is 0 μm (T _o −T _o ′): 9 ° C., which is sufficient for detection. Even when λ _{s is} 23 W / (m · k), when δ is 50 μm, (T _o −T _o ′) is 0.8 ° C., which is sufficient for detection. When the temperature difference is small, the value is set to a constant value with a larger calorific value.

From the above, even if the thermal conductivity of the deposit 3 is equivalent to that of the heat insulating material, even if it is a substance close to glass or ceramics, Q _i is several tens to 100 W, and the total input power Q is several tens of W to several watts. If 100 W is applied, the temperature difference (T _o −
T o _') is obtained as an amount capable of detecting in the state of temperature measurement technology.

The thermal conductivity λ _s of the deposit 3 is 1 for the actual pipe.
Degree, the thickness δ of the deposit and (T _o −T _o ′) can be determined by actual measurement, and thereafter can be treated as a constant value.

In addition, the result of FIG. 15 (a) shows the thermal resistance δ / λ _s of the deposit 3.
If it is scaled as the relationship between and (T _o −T _o ′), FIG.
As shown in (b), it is almost 1 regardless of the thermal conductivity of the deposit.
It is obtained as a linear relationship in the book, and this graph is easier to use from the evaluation of heat transfer characteristics.

Next, when the heat transfer coefficient h to the outside world can be regarded as constant, the relationship between the heat loss Q _o to the outside world and the thickness δ of the deposit 3 is calculated to obtain the 16th value.
Shown in the figure. The solid line is without insulation, and the dotted line is with insulation thickness: 10 mm. In either case, since the thickness δ of the deposit and the heat flow Q _o are obtained as a linear relationship, the thickness δ can be evaluated from the heat flow Q _o using this relationship.

EFFECTS OF THE INVENTION As described above, the method and apparatus according to the present invention detect the adhesion state and thickness of the adhered matter by using the sensor, the heating power source, the temperature detector and / or the heat flow measuring instrument. Therefore, the heat transfer characteristics can be grasped, and the sponge ball insertion time for removing the adhered matter can be effectively determined according to the adhered state, so that the heat transfer efficiency is not deteriorated. It becomes possible to control to the above, and a remarkable effect is produced in practical use.

[Brief description of drawings]

1 (a) and 1 (b) show an example of a model for explaining the present invention. FIG. 1 (a) is a longitudinal sectional view, and FIG. 1 (b) is FIG. 1 (a).
FIG. 2 is a sectional view taken along line I-I of FIG.
(b) Corresponding figure, FIG. 3 is a longitudinal sectional view showing a state in which the sensor is attached to the heat exchanger, and FIGS. 4 (a) and (b) to 13 show a sensor having a heater on the entire circumference of the pipe. Fig. 4
(a) is a longitudinal sectional view of a sensor in which a thermometer for measuring the temperature of the outer wall of the tube is attached within the range of the heater. Fig. 4 (b) is Fig. 4 (a).
IV-IV sectional view taken along line IV-IV of FIG. 5, FIG. 5 (a) shows a sensor in which FIG. 4 is divided into two parts, FIG. 4 (b) shows a corresponding view, and FIG. 5 (b) shows the arrangement of heaters. FIG. 6 is a vertical cross-sectional view of a sensor having a heater and a thermometer on the outer wall of a tube apart from the heater. FIG. 7 is a vertical cross-sectional view of a sensor having a heat flow meter inside or outside the heater. Fig. 8 is a longitudinal sectional view of a sensor in which a thermometer is attached to the outer wall of the heater within the range of the heater, and a heat flow meter is attached to the outer side of the heater. Fig. 10 is a vertical cross-sectional view of a sensor with a heat flow meter installed inside the sensor. Fig. 10 shows a vertical section of the sensor with a thermometer installed on the outer wall of the tube in the range of the heater and an electric power measuring device that keeps the temperature of this thermometer constant. Plan, FIG. 11, FIG. 12,
FIG. 13 is a longitudinal sectional view of the sensor shown in FIG. 8 and FIG. 9 and FIG. 10 in which a thermometer is attached to the outer wall of the tube which is separated from the heater range, and FIGS. 14 (a) (b) (c). ) Is a diagram showing a connection state of a power source, a temperature measuring device, and a heat flow measuring device to various sensors, and FIG. 15 (a) is a thickness δ of the deposits having different thermal conductivities and (T _o −T _o ′). Fig. 15 showing the relationship with
(b) is a diagram showing the relationship between the value obtained by dividing the thickness of the deposit by the thermal conductivity of the deposit and (T _o −T _o ′). FIG. 16 shows that the heat transfer coefficient to the outside is constant. FIG. 6 is a diagram showing the relationship between the thickness of the deposit and the heat loss to the outside, when the heat insulating material is present and when it is not. 1 ... Heater, 2 ... Pipe, 3 ... Adhesion matter, 4
...... Fluid, 5 …… Insulation material, 11 …… Sensor mounted on ordinary pipe, 12 …… Sensor mounted on dummy pipe,
13 ... Dummy pipe, 14 ... Lead wire, 15 ... Hatch, 16.16 '... Thermometer, 17.17' ... Heat flow meter, 18 ... Structural material, 19 ... Temperature measuring device, 20 ... …
Heat flow measuring device, 21 ... Power supply, 22 ... Constant power, 23
...... Power measurement device, A ... Sensor, l ... Pipe length direction part, P ... heater length center, δ ... adhesion thickness, Q ... heater total heat generation amount, Q _{i ......} inside to heat flow, Q o _...... outside to heat flow, T o _...... deposits of certain pipe outer wall temperature, T o _'no ...... deposits pipe outer wall temperature,
T _i ∙ pipe inner wall temperature, λ ∙ thermal conductivity of pipe material, γ _o ∙ pipe outer radius, γ _i ∙ pipe inner radius, T _s ∶ fluid surface temperature of deposit, λ _s ...... The thermal conductivity of the deposit, γ _s , the radius to the inner surface of the deposit, T _f ...
… Temperature of the fluid flowing through the center of the pipe, T _f …… Temperature of the outer wall of the pipe sufficiently distant from the heater, α …… Heat transfer coefficient, T∝ ……
Ambient temperature, h ... Heat transfer coefficient from heat insulating material surface, λ _a
Thermal conductivity of heat insulating material, γ _a ... Radius to outer surface of heat insulating material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shigeru Koyama 1-2-2 Yamato-cho, Kasuga-shi, Fukuoka (72) Inventor Miaki Arakawa 4-22-1006 Wakabadai, Asahi-ku, Yokohama-shi, Kanagawa (56) Reference Reference Hiroshi Yamauchi "Mechanical Engineering Pocketbook" 3rd Edition (Sho 33-7-31) Ohmsha P. 620-621 Shoji Isshiki "Heat Transfer Engineering" 5th Edition (Sho 46-1-10) Morikita Publishing P.P. 16-27

Claims (7)

[Claims] Claim: What is claimed is: 1. A constant amount of heat is applied per unit time to the outer circumference of a pipe through which a fluid flows, and the temperature change of the outer wall of the pipe or the change of heat flow caused by the deposits adhering to the inside of the pipe is measured. Adhesion situation detection method. 2. A variable heat quantity is supplied to the outer circumference of a tube through which a fluid flows, and the variable heat quantity is supplied by monitoring the temperature of the tube so as not to change the temperature change of the outer wall of the tube caused by deposits in the tube. A method for detecting the state of deposits in a fluid pipe, characterized by measuring the amount of heat or the heat flow. 3. A heater provided in a predetermined range on the outer circumference of a pipe through which a fluid flows to give a constant amount of heat to the outer circumference of the pipe per unit time, and a heater provided at least on the outer circumference of the pipe provided with the heater. An adhering matter state detecting device in a fluid pipe, comprising: one or more thermometers for measuring a change in outer wall temperature of the pipe. 4. A thermometer is provided at each of the heater mounting portion on the outer peripheral side of the tube and the outer peripheral portion of the tube remote from the heater mounting portion. A device for detecting a state of adhered matter in a fluid pipe as described above. 5. A heater provided in a predetermined range on the outer periphery of a pipe through which a fluid flows to give a constant amount of heat to the outer periphery of the pipe, and a heater provided at least on the outer peripheral side of the pipe provided with the heater. An adhering matter state detecting device in a fluid pipe, comprising: one or more heat flow meters for measuring a change in heat flow of an outer wall of the pipe. 6. A heater provided in a predetermined range on the outer periphery of a pipe through which a fluid flows to give a variable amount of heat to the outer periphery of the pipe, and an outer wall temperature of the pipe provided at least on the outer periphery of the pipe provided with the heater. One or more thermometers for measuring the temperature of the pipe and a variable amount of heat by the heater for the pipe depending on the result of the temperature monitor of the pipe outer wall so as not to cause the temperature change of the pipe outer wall due to the deposits in the pipe. Power supply to increase and decrease,
An adhering condition detecting device in a fluid pipe, comprising: a measuring device for measuring the amount of electric power supplied to the heater. 7. A thermometer is provided at each of the heater mounting portion on the outer peripheral side of the tube and the outer peripheral portion of the tube remote from the heater mounting portion. A device for detecting a state of adhered matter in a fluid pipe as described above.