JPS60177772A - Case of television camera - Google Patents

Abstract

PURPOSE:To watch abnormal states in an atomic lamp container under high temperature environment by improving the cooling efficiency of a TV camera case. CONSTITUTION:An inner case 7 and the finned outer case 8 of the case and the part other than cooling module are wholly made of aluminium, and a good heat insulating material 10 such as rock wool etc. is packet between the two cases. A window for lens in front of the case is doubly glassed. Heat of 27b, 27c transmitted from the outer case 8 to the inner case through the heat insulating material 10 is attracted again from the inner case to the cooling module, and consequently, does not come into the inner case. Accordingly, intrusion of heat into the inner case is made only through the double glassed window 20 in front of the case. The intruded heat 21 and heat generation of the camera 17 are transmitted to the inner case 7b and carried to the outer case 8b by the cooling module 9. Accordingly, cooling efficiency higher than conventional technique can be obtained by a cooling module having the same cooling capacity as used in conventional techniques.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to the protection of a TV camera in a high-temperature environment, and relates to the structure of a TV left camera case suitable for camera cooling using a Beltier element.

[Background of the invention]

Figure 1 shows the overall system configuration. The TV camera is placed in a harsh environment such as a nuclear reactor containment vessel.
Capturing an image of the object to be inspected and displaying the image on the TV screen 6? send. The effective temperature of the T'V camera is around 40C, whereas the temperature inside the reactor containment vessel is 60-70C even during normal operation.
``C'', and is expected to reach 900 or more in the event of an abnormality. Therefore, in order to monitor the containment vessel and detect and respond to abnormalities at an early stage, K must be set at an environmental temperature of 7 (] iC ~ 90t?). But inside the camera case? It must be cooled below the effective temperature of the camera.

FIG. 2 shows a cross-sectional view of a conventional TV left camera. The cooling module 9 is composed of a large number of Vertier elements connected thermally in parallel and electrically in series, and includes a heat absorption surface, an inner case aluminum block 33, and a heat radiation surface. It is brought into contact with the outer case aluminum fin 34. inner case, outer case,
Except for the contact area of the cooling module mentioned above, cover the sides and rear with 12m + 12b of heat insulating material such as glass epoxy, and in between?
It is insulated with air 35. The front of the case is insulated with a lens glass window 11Kj. A cooling design is adopted in which the heat sucked up by the aluminum fins 34 by the cooling module is carried away by forced convection by the fan 13 in the fan air duct 14.

Is there a simplified diagram of a Bertier element in Figure 3? show.

The Bertier element is an N-type semiconductor 15, P with high thermoelectric performance.
It is electrically connected in series to the type semiconductor 16, and actively transports heat from the heat absorption surface 17 to the heat radiation surface 18 by supplying DC power.

The amount of heat absorbed Q l n 1 and the amount of heat released Q eat is given by the following equation.

Here, α, FL, and K are the Seebeck coefficient, electrical resistance, and thermal conductivity of the Bertier element, respectively, ■ is the DC current, Tl11 is the temperature on the heat absorption side, and T o and t are the temperatures on the heat radiation side.
show. The first term in each equation is due to the Peltier effect, and the amount of heat transported is proportional to the magnitude of the current I and the temperature (absolute temperature).

The second term is given on the assumption that the Joule heat (IR2) generated by the electrical resistance R when a current (2) flows through the conductor contributes half to both heat absorption and heat radiation. The third term is an equation that gives heat conduction due to the temperature difference between the heat radiation side and the heat absorption side.

The structure of the conventional TV left camera case is that the inner case is made of an aluminum block 33, which is a good heat conductor, and a heat insulating material 12, such as glass epoxy. It is composed of:

The aluminum block 33 is a heat transfer body that contacts the heat absorption part of the cooling module 9 and transfers the heat inside the case to the cooling module 9. The heat is transported by the cooling module to the outer aluminum fin 34 and released from the fin surface. Ru. The outer case insulation material 12b% nitrogen 35, the inner case 123, and the glass window 11 prevent heat from outside air from entering the camera case.

Figure 4 shows an outline of heat transport in the conventional technology. This is what is shown.

The amount of heat that infiltrates into the case 111!1 is the sum of the intrusion heat 29 from the glass window and the intrusion heat 30 from the case insulation material. The cooling module must dissipate this intruded heat and the internal heat generated by the camera itself to the outside of the case. Because of this, in the case? In order to maintain the temperature below the effective temperature level, it is necessary to install a large number of expensive cooling modules, and this has the disadvantage that cooling efficiency is poor and uneconomical, such as increased consumption of DC power.

[Purpose of the invention]

Is the purpose of the present invention to monitor abnormal conditions in the high temperature environment inside the reactor containment vessel? In order to improve the cooling efficiency of the TV left camera in a low cost and easy way? We will suggest all possible ways to improve it.

[Summary of the invention]

FIG. 5 shows a cross-sectional view of a camera case structure according to the present invention.

Both the inner case 7 and the outer case 8 with fins are made entirely of aluminum except for the cooling module part, and the h]
It is packed with 10 pieces of good insulation material such as rock wool. In addition, the lens window on the front of the case is made of 72-layer glass.

Figure 6 shows an overview of heat transport.

The outer camera case temperature Tb is slightly higher than the environmental temperature q+a, and the heat of the camera case 26 b f'f: hk is dissipated from the surface of the case 8, but the heat of the outside air does not enter the case. Insulation material lOgesuke 17 outer case 8
J: The heat 27b and 27° conducted to the inner case is absorbed from the inner case into the cooling module 9 again, so it does not enter the inner case. Therefore, the heat intrusion into the inner case is from the front of the case. This intruding heat 21 and the heat generated by the camera 17 are transmitted to the inner case 7b, and are transferred to the outer case 8 by the cooling module 9.
transported to b. Therefore, the same cooling capacity as used in the prior art? With this cooling module, it is possible to obtain cooling efficiency higher than that of conventional technology.

[Embodiments of the invention]

In order to concretely proceed with the cooling design according to the present invention, a numerical analysis using modeling was performed as a means of estimating the number of cooling modules required to maintain the case inner compartment temperature below the effective temperature. -), and by experiment, f! Similar results were obtained for 1 m.

For the structure of the case, we assembled 15 multidimensional linear equations that give heat transport and energy conservation in a steady state with constant environmental temperature T, and solved them to calculate the temperature of each part.

Figures 7 and 8 show the variables used in the modeling.

In this design, a two-stage module 36, 37 and an aluminum block 38 are used to connect the inner case 7 and the outer fin 8.

FIG. 8 is the same cross-sectional view as the fifth and sixth figures, and FIG. 7 is a cross-sectional view of the camera case viewed from the front (or rear).

Q, T, λ, and δ in the figure represent the transport heat, absolute temperature, thermal conductivity, and thickness t of each part, respectively. In addition to these parameters, the surface area A5 of each part, the air transfer coefficient α1, the fin efficiency φ, the number N of cooling modules, etc. are used.

15 variables of temperature and transport heat (Tl, Tz, Ta
.

T41 Tl1jTic lTt glue Ql+ r QIR
* Qt * Q2RIQ1・T・Q+tr s・QI
RB I QRm) versus [-112 heat transport equations,
I assembled three energy storage units.

Heat transport formula % formula % ) )) ) )) Conservation of energy Q2=Q,, ■ NQ, + =Q--, +Ql-F+Ql++s+Q+,
a @NQ! =Qt, s+QRA @ Figure 9 shows the results of the above 15 equations and the temperature of each part. When the environmental temperature is 70C and there are 8 modules, this agrees with the experimental value, and based on this, it can be predicted that if the number of modules is 12, the effective temperature can be maintained at around 35C, which is 400C or less.

Same model? When applied to an environmental temperature of 90C, the required number of modules was 17.

What are the main values of the rose makeup used in the calculation? write down

Seebeck coefficient a, = o, OI IJ/deg
) α, = 0, Ol Heat transfer coefficient L, = 0.116 [VMdeg]Lz
= 0.194 DC current 11 = 2.7 [A) I, = 4.5 Electrical resistance R, = O, 0O0447 (Ω)] 1%, =# Insulation material thermal conductivity λd = 0.004CW name 1-deg
]Aluminum thermal conductivity λ0. λ1. λ2=2.28 Air heat transfer coefficient α, =5.81XIO-'C%/2m2@
deg) Fin efficiency φ is calculated from air density, fan wind speed, fin surface area, air heat transfer coefficient, etc.

In addition, the number of modules N is the first stage module, the second stage module 1
set? It is counted as one piece and is calculated by the number of meters.

In the above invention, the front surface of the camera case is a double glass window, but the space between the two type glasses is usually filled with air.

For this reason, there is heat conduction due to convection, but it goes without saying that if you create a structure that is close to a vacuum, you will have a better insulation effect.

Similarly, in the case of heat insulating materials, it is desirable to manufacture them in a vacuum state if possible, but this requires a sturdy structure in terms of pressure resistance, which has the disadvantage of increasing weight or increasing size. So, what about rock wool? Lightly packed, air convection? It is preferable to make it less likely to occur. On the other hand, if the material is tightened too tightly, the thermal conductivity of the material will be greatly affected, so it is necessary to tighten it moderately. [Effects of the Invention] According to the present invention, the TV camera 2 that is placed in a high temperature environment? In the method of cooling using a cooling module, there is an effect that high cooling efficiency can be obtained.

This allows for monitoring using cameras inside the reactor containment vessel, which has been difficult in the past. This process can be performed not only during normal operation but also under abnormal high temperatures, ensuring excellent machining performance and maintainability. It is expected that this will be useful in improving the operating rate and safety of nuclear couplants.

[Brief explanation of the drawing]

Figure 1 is an overall configuration diagram of a TV monitor that is visually inspected in a high-temperature environment, Figure 3 is a simple diagram of the operation principle of the Beltier element, Figure 2 is a diagram of the structure of the TV right camera according to the prior art, and Figure 4 is its Overview of heat transport? Figure 5 is a structural diagram of the camera case according to the present invention, Figure 6 is a diagram showing an overview of its heat transport, Figures 7 and 8 are diagrams showing variables and parameters in modeling, and Figure 9 is a numerical diagram. Results of analysis? FIG. l... TV left camera 2... lens, 3... TV right camera, 4... reactor containment vessel wall, 5... image signal cable, 6... TV screen, 7... Inner camera case, 8... Outer camera case with fin, 9...
Cooling module, lO... Good insulation material, 11... Case front glass window, 12,... Inner case insulation material, 12
b... Outer case insulation material, 13... Fan, 14.
...Fan ventilation actuator, 15...N-type semiconductor, 16
... P-type semiconductor, 17 ... Heat absorption surface, 18 ... Heat generation surface, 19 ... Electric conductor, 20 ... Heat radiation fin, 2
1...DC power supply, 22...Beltier element heat absorption QI
,,,23... Peltier element heat radiation amount Q oat+24
,．． 24b...Cooling module endothermic amount, 25. . 25b... Cooling module heat radiation amount, 26. ,26b...
・Outer case heat radiation amount, 27. ．． 27b, 27°...
Amount of heat transferred from the outer O11 case to the inner case, 28...
・Camera heat generation amount, 29...Heat intrusion from the front glass window, 30...Heat intrusion from the insulation material, 31...2 ivy glass windows on the front of the case, 32...2 heat intrusion from the front glass window. Intrusion heat of 33...Inner case aluminum block, 34...
Outer case aluminum fin, 35...air, 36...
1st stage mo) knee /shi, 37...2nd stage module, 38...aluminum block. Agent Patent Attorney Akio Takahashi Flute 1 Diagram YZ Diagram □□□-1" Figure 9

Claims (1)

[Claims] 1. Video? A camera and a camera to capture it? A means of covering the lens with a good heat conductor A that wraps and contacts as much as possible except for parts of the lens, a means of covering with a heat insulator that wraps this good heat conductor Ak, and this heat insulator? It is characterized by having a means for enclosing as much as possible with the good heat conductor B, and a means for connecting the good heat conductor A and the good heat conductor B' at the low temperature part and the high temperature part of the Vertier element to conduct heat. TV camera case. 2. In claim 1, in front of the lens? Case 3 of a television camera characterized in that it is double-glazed and provided with a means for completely restricting the inflow and outflow of heat. A television camera case that has a means for spraying coolant.