JPH0587881U - Inspection device for heaters for heating pipes - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to an inspection device for a heater for heating a pipe, and detects an abnormality in the heater promptly and reliably while the power is on. [Structure] Detects the unbalanced phenomenon of the primary circuit by connecting to the current transformer, which is a current transformer in which the power supply lines of a plurality of heaters of the same specification that are energized in parallel are arranged in the forward and reverse directions, respectively, and the secondary circuit of the current transformer And an abnormality detecting means for doing so. When an unbalanced current flows in the primary circuit, the abnormality detecting means is activated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an inspection device for a heater for heating a pipe, and more particularly to a technique for inspecting the soundness of a heater for heating and retaining the sodium sodium insertion pipe used in a fast breeder reactor.

[0002]

[Prior Art]

 Metallic sodium is used as a coolant in the fast breeder reactor. Since the melting point of sodium metal is approximately 98 ° C, it is necessary to preheat the piping to fluidize the metallic sodium when starting below the melting point. Further, even during the operation of the fast breeder reactor, in order to ensure smooth distribution of metallic sodium, heating and keeping at about 200 ° C. are performed.

FIG. 2 shows an example of piping for inserting metallic sodium and a heater for heating. In FIG. 2, reference numeral 1 is a pipe, 2 is a heat insulating material, 3 is a heater, 4 is a power source, and 5 is a switch. The heater 3 is divided into a plurality of pipe lines and is arranged in series along the longitudinal direction of the pipe 1 so as to heat the lower portion of the pipe 1.

In such a pipeline, if even one of the plurality of heaters 3 is disconnected, a cold spot (a low temperature portion that is not heated) is generated. It is necessary to inspect resistance fluctuations as needed. On the other hand, in the example of FIG. 2, since the switch 5 is installed in the power feeding circuit of each heater 3, the heater is managed by interrupting the circuit with the switch 5 and individually measuring the resistance value. be able to.

[0005]

[Problems to be solved by the device]

 However, in the entire pipeline of the fast breeder reactor, the number of heaters 3 is often set to, for example, several hundreds to several thousands, and if the resistance value of each of these heaters is measured individually, it is enormous. Labor is required.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to detect the occurrence of an abnormality in a heater promptly and reliably while the power is on.

[0007]

[Means for Solving the Problems]

 The inspection device for heaters for heating pipes according to the present invention is for inspecting the quality of a plurality of heaters for heating pipes that are energized in parallel, and half of the power supply lines of even heaters of the same specifications are arranged as the primary circuit. In addition, the other half is used as a primary circuit in a reverse direction and a current transformer is connected to the secondary circuit of the current transformer, and an anomaly detection means for detecting an imbalance phenomenon in the primary circuit is adopted. There is.

[0008]

[Action]

 When an even number of heaters are connected in parallel and supplied with power, half of the supplied current flows in opposite directions to the primary circuit of the current transformer, so in normal conditions the magnetic fields may cancel each other, but If a part of the wire breaks or the resistance value fluctuates, a magnetic field is formed based on the unbalanced current, and the abnormality detecting means of the secondary circuit is activated to detect the abnormality.

[0009]

【Example】

 An embodiment of a pipe heating heater inspection apparatus according to the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 4a is a feeder line, 6 is a distribution box, 7 is a current transformer, 7a is a primary circuit (primary conductor), 7b is a secondary circuit, and 8 is an abnormality detecting means (for example, a galvanometer or an alarm is issued). Equipment).

The pipe heating heaters (heaters) 3 are energized in parallel. For example, an even number of the same specifications (same type) of about 200 V and 300 watts are prepared. Will be installed along.

The power supply 4 is, for example, a commercial frequency AC power supply.

The switch 5 is inserted into the power supply line 4 a between the heater 3 and the power source 4 to open and close the circuit, and is housed in the distribution box 6 in FIG. 1.

Inside the distribution box 6, a current transformer 7, its primary circuit 7 a and secondary circuit 7 b are housed.

The current transformer 7 is, for example, a zero-phase current transformer of a primary conductor penetration type or a general current transformer, and half of the primary conductor 7 a connecting the heater 3 and the switch 5 has a forward direction. Is set so as to penetrate the current transformer 7, and the other half of the primary conductor 7a penetrates the current transformer 7 in the opposite direction. Then, the secondary circuit 7b of the current transformer 7 is drawn to a desired location outside the distribution box 6.

The abnormality detecting means 8 is connected to the secondary circuit 7b of the current transformer 7, and detects an abnormality of the heater 3 when an output exceeding a threshold value based on the imbalance phenomenon of the primary circuit 7a is present. A simple galvanometer, an ammeter, an alarm lamp, a display device, a buzzer, or a so-called alarm generator such as a combination of these is applied.

In the pipe heating heater inspection device thus configured, when power is supplied to each heater 3 in a state where each switch 5 is closed, the power supply current for two wires is directed in the primary circuit 7a in the forward direction. And the other two supply currents flow in the opposite direction in the primary circuit 7a, and as a result, they cancel each other out, and the output of the secondary circuit 7b ideally becomes zero. That is, in the normal state, the magnetic fields formed by the forward and reverse currents flowing in the primary circuit 7a cancel each other out, so that the abnormality detecting means 8 does not operate. The detection sensitivity in this case is set to a threshold value in consideration of the allowable level of the unbalanced current of the primary circuit 7a.

However, in the case where a part of the heater 3 is broken or the resistance value of the heater 3 fluctuates due to secular change, an unbalanced current flows in the primary circuit 7a, so that the secondary circuit The output of 7b exceeds the threshold value, and the abnormality detecting means 8 is activated to detect the occurrence of the abnormal phenomenon. In this case, since the abnormality detecting means 8 operates by energizing the plurality of heaters 3, it is possible to transfer information of the heaters of the entire pipeline to the central monitoring room or the like for centralized monitoring. it can.

[0018]

[Effect of the device]

 As described above, the pipe heating heater inspection device according to the present invention has the following effects. (1) Detects an unbalanced phenomenon in the primary circuit, which is connected to a current transformer in which the power supply lines of a plurality of heaters of the same specifications that are energized in parallel are arranged in the forward and reverse directions and the secondary circuit of the current transformer. The abnormality occurrence means can be quickly detected by monitoring the output of the secondary circuit while the heater is energized. (2) Since the current transformer is interposed in the heater power supply line, the entire heater installation range can be comprehensively detected without being affected by the number of heaters installed. (3) Since the operation is performed due to the imbalance of the power supply current, it is possible to reliably detect the occurrence of the heater wire breakage, the resistance variation phenomenon, and the like.

[Brief description of drawings]

FIG. 1 is a connection diagram showing an embodiment of a pipe heating heater inspection device according to the present invention.

FIG. 2 is a connection diagram showing an example of a pipe through which metallic sodium is inserted and a heater for heating.

[Explanation of symbols]

 1 piping 2 heat insulating material 3 heater 4 power supply 4a power supply line 5 switch 6 distribution box 7 current transformer 7a primary circuit (primary conductor) 7b secondary circuit 8 abnormality detection means (galvanometer, alarm generator),

Claims (1)

[Scope of utility model registration request] 1. A device for inspecting the quality of a plurality of heaters for heating pipes that are energized in parallel, wherein half of the power supply lines of even heaters of the same specifications are arranged as a primary circuit and the other half is formed as a primary circuit. An apparatus for inspecting a heater for pipe heating, comprising: a current transformer arranged in a reverse direction; and an abnormality detecting means connected to a secondary circuit of the current transformer to detect an unbalanced phenomenon of a primary circuit.