JP2607635B2 - Explosion-proof electronic weigher - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an explosion-proof electronic weigher used in an environment of an explosive gas or vapor atmosphere.

2. Description of the Related Art An electronic weigher of this type is configured as shown in FIG. In order to install the electric indicator 1 and the load converter 2 in the danger area A of the explosive atmosphere, the load converter 2 has an explosion-proof structure and the indicator 1 is placed in an indicator container 3 having the explosion-proof structure. It is configured. Conventionally, power is supplied from the power supply circuit 4 installed in the non-hazardous area B into the indicator container 3 via the electric wire 5 to supply power to the indicator 1 and to the load converter 2 from the power supply circuit 4. The power is supplied by the electric wire 6 via the measuring container 3. The weighing signal of the load converter 2 is sent to the indicator 1 via the electric wire 7 and the indicator container 3
Is displayed so that it can be read from outside.

Wires 5, 6, and 7 are contained in flameproof explosion-proof piping.
A safety barrier 8 as an intrinsically safe circuit is interposed between the power supply circuit 4 and the indicator container 3.

Problems to be Solved by the Invention In such a conventional configuration, in order to maintain explosion-proof safety, a pressure-resistant explosion-proof pipe of the electric wire 5 and a safety barrier 8 are provided, but a long distance from the non-dangerous place B to the dangerous place A is provided. Explosion-proof piping is troublesome and expensive to construct, and improvement is desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide an explosion-proof electronic weigher that can eliminate the need for a long-distance explosion-proof piping and satisfy explosion-proof safety.

Means for Solving the Problems An explosion-proof electronic weighing machine of the present invention supplies power from an indicator container having an explosion-proof structure to a load converter installed outside the indicator container, and weighs the load converter. Output is processed inside the indicator container, and an air turbine is provided outside the indicator container, a generator is provided inside the indicator container, and the air turbine and the generator are penetrated through the indicator container. The shaft is inserted through the hole, and the air turbine is driven by high-pressure air to supply power to the load converter with the power generated by the generator, and the gap between the shaft and the through-hole and the depth of the gap are defined by a flame. It is set to a value that does not cause runaway.

A pressure-resistant explosion-proof electronic weigher according to a second aspect is characterized in that a secondary battery is added to the output of the generator having the configuration of the first aspect, and power is supplied from the output of the secondary battery.

According to the configuration of the first aspect, the air turbine is driven by the high-pressure air in the danger area, and the generator is driven by the air turbine to obtain the power required by the indicator and the load converter. Therefore, external power supply to the indicator container is not required.

According to the configuration of claim 2, power is supplied from the secondary battery charged by the output of the generator to the indicator and the load converter. Therefore, even if the pressure of the high-pressure air fluctuates, the fluctuation of the power supply voltage can be reduced.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1 and FIG. It is to be noted that components having the same functions as those of the conventional example are denoted by the same reference numerals and described.

FIG. 1 shows an embodiment of the present invention. An air turbine 10 is provided outside the indicator container 3, and a generator 11 is provided inside the indicator container 3 in addition to the indicator circuit 9 of the indicator 1. The air turbine 10 and the generator 11 are connected to the indicator container 3
Are connected by a shaft 13 inserted through a through hole 12 formed in the hole. The air turbine 10 is supplied with high-pressure air 16 taken out through a branch fitting 15 attached to a high-pressure air pipe 14, and the high-pressure air 16 rotates the air turbine 10 to release used air 17. Is done. When the air turbine 10 rotates, the generator 11 is rotationally driven via the shaft 13,
The voltage generated at the output of 11 is supplied to the indicator circuit 9 inside the same indicator container 3 and to the load converter 2 via the electric wire 6. Furthermore, the through hole 12 and the shaft 13
And the depth l of the gap g are set to values that do not cause flame escape.

With such a configuration, a power source can be generated from the high-pressure air 16 obtained from the high-pressure air pipe 13 already provided in the hazardous area A, and the conventional explosion-proof explosion-proof pipe from the non-hazardous area B to the hazardous area A is provided. The safety can be maintained without providing a security device. Moreover, since the generator 11 is provided inside the indicator container 3, even if the explosion-proof structure of the generator 11 is particularly simple, the indicator container 3 can sufficiently fulfill its function. . Also, the depth of the gap between the through hole 12 and the shaft 13 is set to a value that does not cause flame escape, and the shaft 13 is extended outside the indicator container 3 while maintaining safety, and the indicator is Since the air turbine 10 is provided outside the container 3, an increase in the volume of the indicator container 3 can be suppressed slightly.

FIG. 2 shows a second embodiment of the present invention. Here generator 11
, The secondary battery 18 provided in the same indicator container 3 is charged, and the output of the secondary battery 18 is supplied to the indicator circuit 9 and the load converter 2. Even if pressure fluctuations occur due to instantaneous interruption or disturbance, fluctuations in the power supply voltage accompanying the fluctuations can be reduced, and stable operation of the indicator circuit 9 and the load converter 2 can be expected.

In the above embodiment, `` charging '' refers to floating charging, or charging the secondary battery 18 during standby, and cutting out the charging circuit during operation and supplying power only from the secondary battery 18. means.

Advantageous Effects of the Invention As described above, according to the present invention described in each claim, a generator is provided inside the indicator container, and the generator is rotated by the air turbine arranged outside the indicator container. No power is supplied to the indicator container, only the air turbine is turned by high-pressure air to turn the generator, and it is safe, and there is no need for conventional explosion-proof piping and safety barriers for power supply. It is easy to install in a hazardous area.

According to the configuration of claim 2, since power is supplied after charging the secondary battery, fluctuations in the power supply voltage can be reduced even if pressure fluctuations of high-pressure air occur, and stable operation can be realized. It is.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of an indicator container showing an embodiment according to claim 1, FIG. 2 is a partially cutaway front view of an indicator container showing an embodiment according to claim 2, FIG. 3 is a block diagram of a conventional explosion-proof electronic weigher. A: dangerous place, 2: load conversion unit, 3: indicator container, 9: indicator circuit, 10: air turbine, 11: generator, 12: through hole, 13: shaft, 14… High pressure air piping, 16… High pressure air.

Claims (2)

(57) [Claims] A power supply is supplied from an indicator container having an explosion-proof structure to a load converter installed outside the indicator container, and a weighed output of the load converter is processed inside the indicator container. An air turbine is provided outside the indicator container, a generator is provided inside the indicator container, and the air turbine and the generator are connected by a shaft inserted through a through hole of the indicator container. A pressure-resistant explosion-proof electronic meter that is driven by air to supply power to the load conversion unit with the generated power of the generator, and that the gap between the shaft and the through hole and the depth of the gap are set to values that do not cause flame escape. Heavy machinery. 2. An indicator container having an explosion proof structure supplies power to a load converter installed outside the indicator container, and a weighed output of the load converter is processed inside the indicator container. Providing an air turbine outside the indicator container, providing a generator and a secondary battery inside the indicator container, connecting the air turbine and the generator with a shaft inserted through a through hole of the indicator container, An air turbine is driven by high-pressure air to supply power from the secondary battery charged with the generated power of the generator to the load conversion unit, and the flame escapes through the gap between the shaft and the through hole and the depth of the gap. Explosion-proof electronic weigher set to a value that does not occur.