JP2022125655A - Measuring device - Google Patents

Abstract

To provide a measuring device that can restrain or avoid smoking from an electric circuit even if a partial short-circuit of the electric circuit occurs.SOLUTION: A comparator 82 comprises: a first input terminal 821 to which a first voltage value V1 is inputted via a time constant circuit from an operational amplifier 81; and a second input terminal 822 to which a predetermined reference voltage value is inputted. The comparator stops operation of a power supply IC 64 when the first voltage value V1 is equal to or larger than the reference voltage value. A reference voltage setting circuit inputs a first reference voltage value V2 as the reference voltage value to the second input terminal 822 when a current value detected by the operational amplifier 81 is less than a second current value smaller than a first current value, and inputs a second reference voltage value V3 smaller than the first reference voltage value V2 as the reference voltage value to the second input terminal 822 when the current value detected by the operational amplifier 81 is equal to or larger than the second current value.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to a measuring device, and more particularly to a measuring device for measuring the temperature and vibration of a steam trap.

In a plant or the like having a steam piping system, condensate (drainage) may occur in the piping system due to heat exchange or heat radiation. If this condensate stays in the piping system, it will cause a decrease in operating efficiency. I have to.

If the sealing performance of the steam trap is impaired due to aged deterioration, malfunction, or the like, steam in the steam piping system leaks to the outside through the steam trap, resulting in unnecessary steam loss. Therefore, the operation of checking the state of the steam trap is performed periodically, such as once a year.

Patent Literature 1 listed below discloses a measuring device and a diagnostic device for diagnosing the state of a steam trap. The measuring device is a portable measuring device, the diagnostic device is a tablet terminal, a laptop computer, or the like, and wireless communication is possible between the measuring device and the diagnostic device. The measuring device includes a temperature sensor that measures the surface temperature of each steam trap, a vibration sensor that measures the vibration intensity of each steam trap, a storage unit that stores measurement data output from the temperature sensor and the vibration sensor, and the measurement A communication unit for transmitting data to the diagnostic device and a display unit are provided. The diagnostic device diagnoses the state (normal or abnormal) of each steam trap based on the measurement data received from the measurement device, and transmits diagnostic data indicating the result of the diagnosis to the measurement device. Based on the diagnostic data received from the diagnostic device, the measuring device displays the diagnostic result of each steam trap on the display unit.

JP 2018-84418 A

The measuring device incorporates a circuit board on which an electric circuit is formed, and driving power is supplied to the electric circuit from a power supply circuit.

FIG. 4 is a diagram showing the configuration of a power supply circuit 100 included in the measuring device. The power supply circuit 100 includes a battery 161 , a fuse element 162 and a power supply IC 164 . The power supply circuit 100 supplies driving power from the battery 161 to the electric circuit 103 .

The power IC 164 has a protection circuit 171 . The protection circuit 171 stops the operation of the power supply IC 164 when a current equal to or greater than a first current value, which is larger than the current value during normal operation, flows through the electric circuit 103 . This protects the electric circuit 103 from an overcurrent equal to or greater than the first current value.

The fuse element 162 cuts off the connection between the battery 161 and the power supply IC 164 when a second current value (for example, several amperes) larger than the first current value flows. This protects the power supply IC 164 and the electric circuit 103 from overcurrent of the second current value or more.

By the way, in the measuring device, if the electrolyte leaks from the battery 161 due to changes in the environment such as temperature or humidity, the electrolyte flows onto the circuit board and causes a partial short circuit in the electric circuit 103 . short) may occur. Partial short-circuiting may occur not only due to leakage of electrolyte from the battery, but also due to dew condensation and the like.

Since a partial short is not a 0 ohm short but a several ohm short, when a partial short occurs, a current larger than the current value during normal operation but smaller than the first current value flows through the electric circuit 103. . Therefore, even if current flows through the electric circuit 103 due to the partial short, the protection circuit 171 and the fuse element 162 do not perform a protection operation. As a result, a current larger than the current value during normal operation continues to flow through the electric circuit 103, which may induce thermal runaway and cause the semiconductor elements and the like forming the electric circuit 103 to emit smoke.

Some plants, such as petroleum complexes, where steam traps are installed, have strict explosion-proof standards. Since a measuring device having an electric circuit 103 that may generate smoke cannot be brought into such a facility, countermeasures against smoke generation when a partial short occurs are an important issue for the measuring device.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and it is an object of the present invention to obtain a measuring device capable of suppressing or avoiding smoke emission from an electric circuit even when a partial short circuit occurs in the electric circuit. With the goal.

A measuring device according to an aspect of the present invention is a measuring device for measuring the temperature and vibration of a steam trap, comprising a probe in contact with the steam trap, and the temperature and vibration of the steam trap transmitted from the probe. An electric circuit that outputs temperature data and vibration data of the steam trap by applying electrical processing including conversion to an electric signal to the vibration, and a power supply circuit that supplies driving power to the electric circuit. and, the power supply circuit includes a battery, a power supply IC connected between the battery and the electric circuit, and a current value of a current flowing from the battery to the power supply IC, and detecting the current value and a control circuit for outputting a first voltage value according to the power supply IC. a protection circuit, wherein the control circuit includes a time constant circuit that imparts a predetermined time constant to the first voltage value output from the detection circuit; and a second input terminal to which a predetermined reference voltage value is input, and the first voltage value input to the first input terminal is input to the second input terminal. a comparison circuit that stops the operation of the power supply IC when the input voltage is equal to or higher than the reference voltage value; a first reference voltage value is input to the second input terminal as the reference voltage value, and when the current value detected by the detection circuit is equal to or greater than the second current value, the reference voltage value is the a reference voltage setting circuit for inputting a second reference voltage value smaller than the first reference voltage value to the second input terminal.

According to this aspect, the control circuit stops the operation of the power supply IC when the first voltage value corresponding to the current value of the current flowing from the battery to the power supply IC is equal to or higher than the reference voltage value. As a result, when a current equal to or greater than the second current value flows through the electric circuit when a partial short occurs, the control circuit stops the operation of the power supply IC, making it possible to suppress or avoid smoke from the electric circuit. becomes.

Moreover, since the first voltage value output from the detection circuit is input to the comparison circuit via the time constant circuit, it is possible to prevent malfunction caused by sudden noise.

Further, the reference voltage setting circuit inputs the first reference voltage value to the second input terminal when the current value detected by the detection circuit is less than the second current value, and the current value detected by the detection circuit is the second input terminal. If it is equal to or greater than two current values, a second reference voltage value smaller than the first reference voltage value is input to the second input terminal. Therefore, even if the current that flows when the partial short occurs repeats increases and decreases in the vicinity of the second current value within the period of the time constant of the time constant circuit, even if the equilibrium state continues. By lowering the reference voltage value from the reference voltage value to the second reference voltage value, it is possible to reliably stop the operation of the power supply IC.

In the above aspect, the second current value is a smoking start current value of the electric circuit.

According to this aspect, the control circuit stops the operation of the power supply IC when a current equal to or greater than the second current value, which is the smoking start current value of the electrical circuit, flows through the electrical circuit. As a result, it is possible to effectively avoid the emission of smoke from the electric circuit due to the partial short.

Advantageous Effects of Invention According to the present invention, even when a partial short circuit occurs in an electric circuit, it is possible to suppress or avoid smoke emission from the electric circuit.

1 is a diagram showing a simplified configuration of a portable measuring device according to an embodiment of the present invention; FIG. 1 is a diagram showing a simplified configuration of a power supply circuit according to the underlying technology of the present invention; FIG. 1 is a diagram showing a simplified configuration of a power supply circuit according to an embodiment of the present invention; FIG. It is a figure which shows the structure of the power supply circuit with which the measuring device which concerns on background art is provided.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Elements with the same reference numerals in different drawings represent the same or corresponding elements.

FIG. 1 is a diagram showing a simplified configuration of a portable measuring device 1 according to an embodiment of the present invention. The measuring device 1 has a function of measuring the temperature and vibration of the steam trap and a function of diagnosing the state of the steam trap based on the measurement results. However, the diagnostic function may be provided by an external device (diagnostic device, server device, or the like) of the measuring device 1 . In addition, the measuring device is not limited to a portable type, and may be an installation type measuring device.

2. Description of the Related Art In a plant or the like equipped with a steam piping system, a plurality of steam traps are installed at appropriate locations in the piping system in order to discharge condensate (drainage) generated in the piping system to the outside of the piping system. The condition of the steam trap is checked by periodic inspection such as once a year. A periodic inspection operator carries the portable measuring device 1 and moves around the plant to inspect each steam trap in turn using the measuring device 1 . Note that the inspection of the steam trap is not limited to periodic inspection, and may be irregular inspection.

The measuring device 1 includes probes (a temperature probe P1 and a vibration probe P2), a power supply circuit 2, and an electric circuit 3. The electric circuit 3 is formed on a circuit board incorporated in the measuring device 1, and includes a temperature sensor 11, an amplifier circuit 12, an AD converter circuit 13, a vibration sensor 21, a filter circuit 22, an amplifier circuit 23, an AD converter circuit 24, It has a control section 31 , an operation section 41 , a display section 42 , a storage section 43 and a communication section 44 .

The temperature probe P1 and the vibration probe P2 have external shapes of cylindrical pipes made of stainless steel, for example. The temperature probe P1 is arranged in a space inside the vibration probe P2 in a non-contact and concentric positional relationship with respect to the inner peripheral surface of the vibration probe P2. The temperature probe P1 and the vibration probe P2 transmit the temperature and vibration of the steam trap to the temperature sensor 11 and the vibration sensor 21 by being brought into contact with the steam trap to be measured.

The temperature sensor 11 includes, for example, a pair of thermocouple wires and a temperature measurement circuit, converts the temperature transmitted from the temperature probe P1 into an electric signal, and outputs the electric signal. An electrical signal output from the temperature sensor 11 is input to the amplifier circuit 12 . The amplifier circuit 12 amplifies the input electrical signal and outputs it. An electrical signal output from the amplifier circuit 12 is input to the AD conversion circuit 13 . The AD conversion circuit 13 converts the input analog electrical signal into digital data and outputs the digital data. Digital data (temperature data) indicating a temperature measurement value output from the AD conversion circuit 13 is input to the control unit 31 .

The vibration sensor 21 includes, for example, a piezoelectric acceleration sensor, converts the vibration transmitted from the vibration probe P2 into an electric signal, and outputs the electric signal. An electrical signal output from the vibration sensor 21 is input to the filter circuit 22 . The filter circuit 22 passes and outputs an electrical signal in a predetermined frequency band among the input electrical signals. The electrical signal output from the filter circuit 22 is input to the amplifier circuit 23 . The amplifier circuit 23 amplifies the input electrical signal and outputs it. The electrical signal output from the amplifier circuit 23 is input to the AD conversion circuit 24 . The AD conversion circuit 24 converts the input analog electrical signal into digital data and outputs the digital data. Digital data (vibration data) indicating the vibration measurement value output from the AD conversion circuit 24 is input to the control unit 31 .

The operation unit 41 includes operation switches and the like for the operator to input various kinds of information. The display unit 42 is configured using a liquid crystal display, an organic EL display, or the like. However, the operation unit 41 and the display unit 42 may be integrated by using a touch panel display. The storage unit 43 is configured using a rewritable semiconductor memory such as a flash memory. The communication unit 44 includes a communication module compatible with any communication method such as Bluetooth (registered trademark).

The control unit 31 is configured including a CPU and the like. The control unit 31 has a diagnosis unit 51 as a function realized by the CPU executing a predetermined program. The diagnosis unit 51 diagnoses the state of the steam trap based on the measurement data (temperature data and vibration data) input from the AD conversion circuits 13 and 24, and outputs diagnosis data indicating the diagnosis result. For example, the diagnosis unit 51 compares the input temperature data with a predetermined temperature threshold, and compares the input vibration data with a predetermined vibration threshold. . The diagnosis unit 51 diagnoses whether the steam trap is normal or abnormal (steam leakage, drain discharge failure, or blockage) according to a combination of these two comparison results. The control unit 31 creates diagnosis result information (inspection date, diagnosis result, etc.) including the diagnosis data of the steam trap, and stores the diagnosis result information in the storage unit 43 . Also, the control unit 31 inputs diagnostic data to the display unit 42 . Thereby, the diagnosis result of the steam trap is displayed on the display unit 42 . Further, the control unit 31 inputs the steam trap diagnosis result information to the communication unit 44 . The communication unit 44 transmits the input diagnostic result information to a data processing device external to the measuring device 1 .

The power supply circuit 2 supplies electric power to the electric circuit 3 for driving each of a plurality of elements (elements, circuits, devices, etc.) included in the electric circuit 3 .

FIG. 2 is a diagram showing a simplified configuration of the power supply circuit 2 according to the underlying technology of the present invention. The power supply circuit 2 includes a battery 61, a fuse element 62, a power supply IC 64, a detection circuit, and a control circuit. The detection circuit includes a resistive element 66 and an operational amplifier 81 . The control circuit includes resistance elements 91 to 93 , a comparator 82 and a capacitor 83 .

A fuse element 62 is connected after the battery 61, a resistance element 66 is connected after the fuse element 62, a power supply IC 64 is connected after the resistance element 66, and a load is connected after the power supply IC 64. An electric circuit 3 is connected. The battery 61 is, for example, an alkaline dry battery. The power supply IC 64 includes, for example, a switching regulator. The power supply circuit 2 supplies drive power from the battery 61 to the electric circuit 3 .

The power supply IC 64 has a protection circuit 71 . The protection circuit 71 stops the operation of the power supply IC 64 when a current equal to or greater than a first current value I1 larger than the current value I0 during normal operation flows through the electric circuit 3 . This protects the electric circuit 3 from an overcurrent equal to or greater than the first current value I1.

In the measuring device 1, if the electrolyte leaks from the battery 61 due to changes in the environment such as temperature or humidity, the electrolyte flows onto the circuit board and causes a partial short circuit in the electric circuit 3. ) may occur. A partial short may occur not only due to leakage of electrolyte from the battery 61 but also due to dew condensation or the like.

Since a partial short is not a 0 ohm short but a few ohm short, when a partial short occurs, a current larger than the current value I0 during normal operation but smaller than the first current value I1 is supplied to the electric circuit 3. flows. Therefore, even if current flows through the electric circuit 3 due to the partial short, the protection circuit 71 does not perform the protection operation.

The current value of the current flowing from the battery 61 to the power supply IC 64 via the resistance element 66 is input to the operational amplifier 81 as the voltage value across the resistance element 66 . The operational amplifier 81 outputs a voltage value corresponding to the input voltage value between both ends. A voltage value output from the operational amplifier 81 is input to the first input terminal of the comparator 82 via a time constant circuit composed of the resistance element 91 and the capacitor 83 . The time constant is set to several seconds to prevent malfunctions caused by momentary noise.

A reference voltage value corresponding to the ratio of the resistance values of the resistance elements 92 and 93 is input to the second input terminal of the comparator 82 . When the voltage value of the first input terminal is less than the voltage value of the second input terminal (that is, when the current value of the current flowing through the resistance element 66 when a partial short occurs is less than the second current value I2), the comparator 82 outputs a relatively high voltage value (high level signal). The second current value I2 is the current value at which the electric circuit 3 starts to emit smoke. Further, the comparator 82 detects when the voltage value of the first input terminal is equal to or higher than the voltage value of the second input terminal (that is, when the current value of the current flowing through the resistive element 66 when a partial short occurs is equal to or higher than the second current value I2). ) outputs a relatively low voltage value (low level signal).

The voltage value output from the comparator 82 is input to the active high enable terminal 65 of the power supply IC 64 . The power supply IC 64 operates when a high level signal is input to the enable terminal 65 and stops operating when a low level signal is input to the enable terminal 65 . Accordingly, when the current value of the current flowing through the resistance element 66 is less than the second current value I2, the power supply IC 64 operates. On the other hand, when the current value of the current flowing through the resistance element 66 is equal to or greater than the second current value I2, the power supply IC 64 stops operating. When the power supply IC 64 stops operating, the supply of driving power to the electric circuit 3 is stopped, so the measuring device 1 stops operating.

The fuse element 62 cuts off the connection between the battery 61 and the resistance element 66 when a current of a third current value I3 (for example, several amperes) larger than the first current value I1 flows. As a result, the power supply IC 64 and the electric circuit 3 are protected from an overcurrent equal to or greater than the third current value I3.

By the way, in the power supply circuit 2 according to the base technology shown in FIG. is provided. Therefore, if the current that flows when a partial short occurs repeats increasing and decreasing within the time constant period of the time constant circuit and in the vicinity of the second current value I2 continues, the operation of the power supply IC 64 is controlled by the comparator 82. cannot be stopped. In order to improve this, the following configuration of the power supply circuit 2 according to the embodiment of the present invention is proposed.

FIG. 3 is a diagram showing a simplified configuration of the power supply circuit 2 according to the embodiment of the invention. The power supply circuit 2 includes a battery 61, a fuse element 62, a power supply IC 64, a detection circuit, and a control circuit. The detection circuit is configured with a resistance element 66 and an operational amplifier 81 . The control circuit includes a time constant circuit, a comparator 82 (comparison circuit), and a reference voltage setting circuit. The time constant circuit is configured including a resistance element 91 and a capacitor 83 . The reference voltage setting circuit includes resistance elements 92 to 96 and a transistor 84 . The ratio of resistance values R1 and R2 of resistance elements 92 and 93 is equal to the ratio of resistance values R4 and R5 of resistance elements 95 and 96. FIG.

The current value of the current flowing from the battery 61 to the power supply IC 64 via the resistance element 66 is input to the operational amplifier 81 as the voltage value across the resistance element 66 . The operational amplifier 81 outputs a voltage value V1 corresponding to the input voltage value between both ends. A voltage value V1 output from the operational amplifier 81 is input to the first input terminal 821 of the comparator 82 via a time constant circuit composed of the resistance element 91 and the capacitor 83 . The time constant of the time constant circuit is set to about several seconds in order to prevent malfunction caused by momentary noise.

A second input terminal 822 of the comparator 82 receives the reference voltage value V2 or the reference voltage value V3. The reference voltage value V2 is a voltage value corresponding to the ratio between the resistance value R1 of the resistance element 92 and the resistance value R2 of the resistance element 93 when the transistor 84 is off. The reference voltage value V3 is a voltage value corresponding to the ratio of the resistance value R1 of the resistance element 92 and the combined resistance value of the resistance values R2 and R3 of the resistance elements 93 and 94 when the transistor 84 is on. The resistor elements 93 and 94 are connected in parallel, and the combined resistance value of the resistor elements 93 and 94 is smaller than the resistance value R2 of the single resistor element 93, so the reference voltage value V3 is smaller than the reference voltage value V2.

When the current value of the current flowing through the resistance element 66 when the partial short occurs is less than the second current value I2, the voltage value V1 is smaller than the threshold value, so the transistor 84 is off and the second input terminal of the comparator 82 is turned off. 822 receives the reference voltage value V2. On the other hand, if the current value of the current flowing through the resistive element 66 when the partial short occurs is equal to or greater than the second current value I2, the voltage value V1 becomes equal to or greater than the threshold value even within the period of the time constant. Therefore, the transistor 84 is turned on, and the reference voltage value V3 is input to the second input terminal 822 of the comparator 82 .

The comparator 82 is high when the voltage value of the first input terminal 821 (voltage value V1 with a time constant) is less than the voltage value of the second input terminal 822 (reference voltage value V2 or reference voltage value V3). It outputs a level signal, and outputs a low level signal when the voltage value of the first input terminal 821 is greater than or equal to the voltage value of the second input terminal 822 . The power supply IC 64 operates when a high level signal is input to the enable terminal 65 and stops operating when a low level signal is input to the enable terminal 65 .

According to the measuring device 1 according to the present embodiment, the control circuit changes the voltage value V1 (first voltage value) corresponding to the current value of the current flowing from the battery 61 to the power supply IC 64 to the reference voltage value V2 or the reference voltage value If it is V3 or more, the operation of the power supply IC 64 is stopped. As a result, when a current equal to or greater than the second current value I2 flows through the electric circuit 3 when a partial short occurs, the control circuit stops the operation of the power supply IC 64, thereby suppressing or avoiding smoke emission from the electric circuit 3. becomes possible.

Moreover, the resistance value of the resistance element 66 is, for example, about 100 milliohms, which is sufficiently small. Therefore, since the internal impedance of the power supply circuit 2 is sufficiently small, the load characteristics of the power supply circuit 2 can be stabilized.

Moreover, since the voltage value V1 output from the operational amplifier 81 is input to the comparator 82 via the time constant circuit, it is possible to prevent malfunction caused by sudden noise.

Further, when the current value detected by the detection circuit is less than the second current value I2, the reference voltage setting circuit inputs the reference voltage value V2 (first reference voltage value) to the second input terminal 822 and detects If the current value detected by the circuit is greater than or equal to the second current value I2, a reference voltage value V3 (second reference voltage value) smaller than the reference voltage value V2 is input to the second input terminal 822 . Therefore, even if the current that flows when a partial short occurs repeats increases and decreases in the vicinity of the second current value I2 within the period of the time constant of the time constant circuit, the reference voltage setting circuit does not set the reference voltage. By lowering the reference voltage value from the voltage value V2 to the reference voltage value V3, the operation of the power supply IC 64 can be reliably stopped.

Further, according to the measuring device 1 according to the present embodiment, the control circuit controls the power supply IC 64 to stop working. This makes it possible to effectively avoid smoke from the electrical circuit 3 due to partial shorts.

1 measuring device 2 power supply circuit 3 electric circuit 61 battery 64 power supply IC
66, 91 to 96 resistance element 71 protection circuit 81 operational amplifier 82 comparator 83 capacitor 84 transistor 821 first input terminal 822 second input terminal P1 temperature probe P2 vibration probe

Claims (2)

A measuring device for measuring the temperature and vibration of a steam trap,
a probe abutted against the steam trap;
an electrical circuit that outputs temperature data and vibration data of the steam trap by performing electrical processing including conversion into electrical signals on the temperature and vibration of the steam trap transmitted from the probe; ,
a power supply circuit that supplies drive power to the electric circuit;
with
The power supply circuit
a battery;
a power supply IC connected between the battery and the electric circuit;
a detection circuit for detecting a current value of the current flowing from the battery to the power supply IC and outputting a first voltage value according to the current value;
a control circuit;
has
the power supply IC includes a protection circuit that stops the operation of the power supply IC when a current equal to or greater than a first current value flows through the electric circuit;
The control circuit is
a time constant circuit that gives a predetermined time constant to the first voltage value output from the detection circuit;
a first input terminal to which the first voltage value is input from the detection circuit via the time constant circuit; and a second input terminal to which a predetermined reference voltage value is input; a comparison circuit that stops the operation of the power supply IC when the input first voltage value is equal to or higher than the reference voltage value input to the second input terminal;
When the current value detected by the detection circuit is less than a second current value that is smaller than the first current value, the first reference voltage value is input to the second input terminal as the reference voltage value, and the detection is performed. Reference voltage setting, wherein a second reference voltage value smaller than the first reference voltage value is input to the second input terminal as the reference voltage value when the current value detected by the circuit is equal to or greater than the second current value. a circuit;
A measuring device. 2. The measuring device according to claim 1, wherein said second current value is a smoking start current value of said electric circuit.

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