JPS62132094A - Self-control type preheater unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a preheating heater for use in a preheating and heat retention control system for sodium equipment, piping, valves, etc. in a fast breeder reactor, and particularly relates to a self-heating heater with a humidity control function. The present invention relates to a controlled preheating heater unit.

[Technical background of the invention and its problems]

In fast breeder reactors, liquid sodium is used as a coolant, but since sodium has a melting point of 98['C], it is usually heated to 200['01] or higher and used as a coolant. Various containers of fast breeder reactors that are filled with or contain sodium.

Enclosures, piping, valves, etc. must be uniformly heated and kept warm at a predetermined temperature increase rate. Electric heaters are usually used as heating sources for these various devices that are objects to be heated.

The power supply to the electric heater cannot be controlled simply by manually turning the switch on and off, so it must be controlled by an experienced expert while observing the readings on the temperature indicator. This is necessary.

However, in a fast breeder reactor, since there are many preheating points and temperature measurement points, sufficient preheating control cannot be performed only by manual operation. Therefore, as mentioned above, a temperature system (goods) that uniformly controls heating and heat retention at a predetermined temperature increase rate is required.
Equipment unit and switch are required.

Next, a conventional preheating and heat retention system will be explained with reference to FIG. 4. In FIG. 4, among various equipment of a fast breeder reactor which is an object to be heated, piping is particularly illustrated as an example. An electric heater 9 and a temperature detector 4 are installed in the piping 1, which is an object to be heated, and a heat insulating material 3 for heat retention is further fixed with a heat insulating material protection tube 2. The temperature signal 7 obtained by the temperature detector 4 is input to the temperature control device unit 18 as a pipe preheating temperature measurement IPV, and is preliminarily determined by temperature.
A comparison calculation is made with the temperature set value SV set in the IAR unit 18. The comparison calculation value 5v-pv is determined by the comparator of the comparison calculation unit, and when SV≧Pv, MV is turned on, and S<PV
If MV turns off, the on/off signal is sent to relay unit 1.
7, and the semiconductor type (
7) IJL/-(SSR:5olid 5tateR
The electric current supplied from the power supply unit 6 to the electric heater 9 is turned on and off by turning on and off the semiconductor SSR.

Because fast breeder reactors use liquid sodium as a coolant, they have a large number of objects to be heated.
The temperature control device unit 18 inputs a plurality of m degree measurement points and controls a plurality of electric heaters 9. In addition, although a microprocessor is used for the temperature control unit 18, there is a limit to the number of input/output points, and one temperature control unit 18 can handle all the heated objects in the fast breeder reactor. It is impossible to perform preheating and heat retention control. For this reason, the temperature control device unit 18 is also usually ? Several units will be required. In addition, multiple temperature control device units 1-18
The monitoring signals from, for example, the surface temperature of the heated object, etc., are collectively input to the monitoring unit 8 installed in the central sub-compartment.
Bulk monitoring is now possible.

In this way, the temperature control device unit 18 performs preheating/warming control of a large number of objects to be heated, so it uses a preheating/warming control algorithm at a predetermined temperature increase rate in consideration of the structure, heat transfer characteristics, etc. of the objects to be heated. needs to be configured. Therefore, when designing the temperature control device unit 18, we thoroughly understand the heat transfer characteristics of the heated object and the heat generation characteristics of the heater, establish a preheating/warming control algorithm based on sufficient heat transfer calculations, and conduct simulation tests. It is necessary to conduct sufficient verification using methods such as Furthermore, in a fast breeder reactor, due to its complicated piping structure, the routing of control signal and measurement signal lines is inevitably complicated, and it is necessary to take sufficient noise countermeasures. Therefore, it has been extremely difficult to put into practice a preheating and heat retention system that can reliably control the temperature increase and heat retention of objects to be heated.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and its purpose is to eliminate the need for elaborately designed multiple preheating/warming algorithms and to eliminate the need for a control device, etc.
It is an object of the present invention to provide a self-controlled preheating unit with a simple configuration that can control the temperature by itself.

[Summary of the invention]

The gist of the present invention is to use a heat-sensitive resistance element with a positive characteristic and a heat-sensitive resistance element with a negative characteristic for temperature control, and to adjust the temperature to a predetermined temperature II If by selecting these temperature characteristics according to the required temperature control. The goal is to do the following.

That is, the present invention provides an electric heater that is installed on an object to be heated and heated by electrical heating; a heat-sensitive resistance element that is installed on the object and has a positive characteristic whose resistance value increases rapidly at a temperature exceeding a set temperature; This is a self-control preheating unit in which the heat-sensitive resistance elements, which are installed on the object to be heated and have a negative characteristic whose resistance value decreases as the temperature rises, are connected in series. , a constant preheating/heating rate is obtained between preset temperature settings.

In addition, when the present invention is applied to a preheating and heat retention system, as a self-controlled preheating heater unit, an electric heater, a heat sensitive resistance element having positive temperature characteristics, and a heat sensitive resistance element having negative temperature characteristics are simply electrically connected in series. Connect and fill the insulated heater tube etc. with magnesium oxide etc. as an insulating material.

A plurality of self-controlled preheating heater units and temperature detectors are installed for the object to be heated. Here, as a self-control preheating unit, a combination of a positive characteristic heat-sensitive resistance element and a negative characteristic heat-sensitive resistance element, which are designed by understanding the characteristics in advance according to the temperature rise situation of the object to be heated, is used. In this case, by changing the resistance according to the resistance-temperature characteristics of the self-controlling preheating unit, on/off control of the voltage application to the electric heater of the self-controlling preheating unit can be performed as a heating element without a control device. The temperature of the object to be heated is set to a temperature set value determined by the resistance-temperature characteristic of the self-controlling preheating unit, which has the function of an on-off controller. It becomes possible to maintain the

The objects to be heated are sodium equipment, piping, valves, etc. of fast breeder reactors, and the heat-sensitive resistance elements with positive temperature characteristics are semiconductors with compositions such as barium titanate, which have negative temperature characteristics. The heat-sensitive resistance elements are Mn, Co, and N.
It is a semiconductor having a composition such as i, Fe, Cu, etc.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing a preheating IS system in which a self-controlled preheating heater unit is installed in piping. A temperature detector 4 for monitoring the surface temperature of the pipe and a self-controlled preheater unit 5 according to the present invention are installed in the heated portion of the pipe 1 and the like. The top is covered with a heat insulating material 3, and finally these are fixed with a heat insulating material protection tube 2.

FIG. 2 shows the internal structure of the self-control preheating unit 5, which includes an electric heater 9, a positive characteristic heat-sensitive resistance element (hereinafter abbreviated as PTC>10), and a negative characteristic heat-sensitive resistance element. (hereinafter abbreviated as NTC) 11 are electrically connected in series, covered with an insulated heater tube 12 filled with magnesium oxide, and voltage is applied from a conducting wire 13.

PTCIO is a semiconductor having a composition such as barium titanate, and has temperature characteristics as shown in FIG. 3(a). In other words, the PTC characteristic curve is expressed by the horizontal axis as temperature and the vertical axis as the logarithm IogR of resistance R. The lower the temperature, the lower the resistance, and the set temperature Tp with the Curie point determined by the PTC composition as the threshold. It has the characteristic that the resistance increases sharply when it exceeds .

Moreover, NTCll is Mn, Co, Ni, and Fe.

It is a semiconductor having a composition such as Cu, and has temperature characteristics as shown in FIG. 3(b). That is, the characteristic curve of NTC is expressed in the same way as that of PTC, and has a characteristic that the resistance is large when the temperature is low, and the resistance value decreases as the temperature increases.

Therefore, electric heater 9. The characteristic curve of the self-preheating heater unit 5 having a configuration in which PTClo and NTc11 are electrically connected in series is as shown in FIG. 3(C). That is, up to the set temperature TN determined by the intersection of the approximately constant resistance value determined by the sum of the resistance value of PTCIO below the threshold value Tρ, which is the cue point of PTCIO, and the resistance value of the electric heater 9, and the negative characteristic curve of NTCll. The self-limiting preheating heater unit 5 has a high resistance value, so even if a voltage is applied, little current flows, and the heat generation of the heater is extremely small. Set temperature T
The threshold determined by the cue point of PTCIO from N to Tp can almost be regarded as the resistance value of the electric heater 9, and since a voltage is applied, current flows to the electric heater 9, and the pipe 1 which is the object to be heated When the threshold value Tp is exceeded, the resistance value changes sharply due to the temperature characteristics of PTClo.
As a result, almost no current flows through the electric heater 9, and the electric heater 9 generates almost no heat.

That is, conventionally, the temperature signal 7 from the temperature detector 4 is controlled by temperature control.
It feeds back to the I+ device 8, and the comparison calculator and relay unit 1 of the comparison section provided inside the temperature control device 18
The self-controlled preheating unit 5 according to the present invention can perform the functions previously performed by the SSR relay, etc. inside the heating element 7.

Next, the operation of this embodiment will be explained.

In the preheating operation of a fast breeder reactor, nium-ion equipment is used.

Objects to be heated, such as valves and piping, are heated and kept warm by the electric heater 9 at a predetermined temperature increase rate, as described above.

By creating a plurality of self-controlled preheating heater units 5 according to the present invention by combining PTClo, NTCll, and electric heaters 9 with slightly different characteristics, and installing them in the piping 1 etc. that is the object to be heated, it is possible to The object to be heated can be heated at a temperature increase rate of .

Furthermore, in a fast breeder reactor, when the heated object reaches a certain set temperature i, it is necessary to stop raising the temperature and shift to heat retention control. Of course, it can be easily implemented by using the deleted version. In other words, a PTC with a characteristic such that the set temperature Tp of PTClo becomes equal to the humidity
If you use , current will flow through the electric heater 9 to heat it up to the set temperature Tp, and when the temperature of the object to be heated exceeds the set temperature Tp, the resistance will become large due to the characteristics of PTClo, and the electric current will flow through the electric heater 9. Since the flow stops, the electric heater 9 is repeatedly turned on and off after the set temperature Tp, and constant humidity control becomes possible.

Therefore, according to this embodiment, by simply applying a voltage to the self-controlled preheating heater unit 5, the temperature control device unit 1
8, the relay unit 17, etc., it is possible to control the temperature increase and heat retention of the pipe 1, which is the object to be heated.

Therefore, there is no need to establish a preheating/warming algorithm or perform various simulations, making it extremely easy to implement. Furthermore, since routing of control signal and measurement signal lines is not necessary, the adverse effects of noise can also be eliminated.

Note that the present invention is not limited to the embodiments described above, and can be implemented with various modifications without departing from the gist thereof. For example, the object to be heated can be a sodium reactor or a valve in a fast breeder reactor instead of a heavy reactor.

Furthermore, the materials and temperature characteristics of the heat-sensitive resistance elements with positive characteristics and negative characteristics can be changed as appropriate according to specifications.

[Effect of light]

As explained above, according to the self-controlled preheating unit of the present invention, there is no need for complex temperature-specific equipment units, semiconductor SSRs, etc. It is possible to reliably preheat and maintain the temperature of valves, etc., and to prevent sodium from freezing.

In addition, when installing the self-controlled preheater unit according to the present invention in various heated objects of a fast breeder reactor, PTC and N
A power supply unit for supplying power to the self-controlled preheater unit and a quality control unit for monitoring the surface temperature of the object to be heated is prepared by preparing a plurality of such units, each consisting of a TC connected in series to an electric heater, with different characteristics. By simply preparing the detector and the monitoring units 1 to 1, it is possible to construct a simple preheating/warming system with good controllability.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a preheating and heat retention system in which a self-sterilizing preheating heater unit according to an embodiment of the present invention is installed in piping, FIG. 2 is a schematic diagram showing the internal configuration of the heater unit, and FIG. The figure is PTC. A characteristic diagram showing the temperature characteristics of the NTC and the heater unit, and FIG. 4 is a schematic configuration diagram showing a conventional preheating temperature control system. 1... Piping (heated object), 2... Heat insulation protection pipe, 3
...Maintenance) S material, 4...Temperature detector, 5...Self-controlled iiO type preheating heater unit, 6...Power supply unit,
7...Temperature signal, 8...Monitoring unit, 9...Electric heater, 10...Positive characteristic heat sensitive resistance element, 11...
negative characteristic heat-sensitive resistance element, 12... insulated heater tube, 13.
・Conducting wire. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 (a) "'" 1 (c) Figure 3

Claims (4)

[Claims] (1) An electric heater installed on the object to be heated and heated by electrical heating, a heat-sensitive resistance element with positive characteristics whose resistance value increases rapidly at a temperature exceeding a set temperature, installed on the object to be heated, and A self-controlling preheating heater comprising a heat-sensitive resistance element with a negative characteristic that is placed on a heated object and whose resistance value decreases as the temperature rises, and the above-mentioned electric heater and each heat-sensitive resistance element are connected in series. unit. (2) The object to be heated is sodium equipment of a fast breeder reactor,
The self-controlled preheating unit according to claim 1, characterized in that it is a pipe or a valve. (3) The self-control preheating unit according to claim 1, wherein the heat-sensitive resistance element with positive characteristics is a semiconductor having a composition such as barium titanate. (4) The negative characteristic heat-sensitive resistance element may include Mn, CoNi,
The self-control preheating unit according to claim 1, characterized in that the self-control preheating unit is made of a semiconductor having a composition of Fe, Cu, or the like.