JP4050900B2 - Mass flow meter adhering matter detection device and cleaning device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mass flow meter that measures the mass of a liquid mixed with solid foreign matters, and relates to an adhering matter detection device and a cleaning device that detect the adhering amount of adhering matter adhering to an inner wall surface of a pipe constituting the measuring unit. .
[0002]
[Prior art]
Conventionally, mass flowmeters including an inflow pipe and an outflow pipe arranged in a straight line in a measurement unit, and a bent pipe connected to these pipes are used for mass measurement of liquid mixed with solid foreign matters. This mass flow meter is configured to calculate the mass of the liquid from the amount of strain of the bent pipe while the liquid mixed with solid foreign matters from the inflow pipe passes through the bent pipe and is discharged from the outflow pipe.
[0003]
[Problems to be solved by the invention]
In this mass flow meter, since the liquid in which solid foreign matters are mixed is measured, fresh water is sent to the measuring unit at the end of measurement, and the inner wall surface of the pipe is cleaned. However, only by repeating this kind of cleaning, solid foreign matters remain as deposits on the inner wall surface of the pipe of the measurement unit, and these deposits cause a measurement error of the liquid density. Therefore, the cleaning liquid is periodically sent to the measuring unit after a predetermined period of time to clean the inner wall surface of the pipe, but there is no method for detecting the degree of cleaning, and it is possible to grasp whether or not the deposit has been removed. There is a need for a solution.
[0004]
The present invention has been invented in view of the above-mentioned demand, and intends to provide a deposit detection device and a cleaning device that detect the amount of deposit on the inner wall surface of the pipe of the measurement unit when the measurement unit is cleaned at the end of measurement. To do.
[0005]
[Means for Solving the Problems]
A bent pipe is arranged between the inflow pipe and the outflow pipe arranged in a straight line, and the amount of strain of the bent pipe while the liquid mixed with solid foreign matters passes through the bent pipe and is discharged from the outflow pipe. In a mass flow meter equipped with a measurement mode that detects mass and calculates the mass of the liquid from this strain amount,
Separately from the measurement mode, an input unit for selecting the detection mode is provided, and the density of fresh water is calculated from the natural frequency of the bent pipe when fresh water is supplied in the detection mode, and this density is stored as the density of fresh water stored in advance. In comparison, the amount of deposit on the inner wall surface of the bent pipe is detected from the difference between the two.
[0006]
In addition, an input unit for selecting the detection mode is provided separately from the measurement mode, and the density of the fresh water is calculated from the natural frequency of the bent pipe when the fresh water is supplied in the detection mode, and this density is stored in advance. The cleaning liquid may be supplied from the inflow pipe when the difference between the two becomes equal to or greater than a predetermined value.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings for a mass flow meter cleaning device. In FIG. 1 and FIG. 2, reference numeral 1 denotes a cleaning device for a mass flow meter 2 that measures the mass of a liquid mixed with solid foreign substances. The adhering matter detection device 3 including the mass flow meter 2, a cleaning liquid supply unit 4, It is made up of. The adhering matter detection device 3 includes a fresh water supply unit 5 having a fresh water pipe 5a connected to a main pump 7 and a mass flow meter 2 and a calculation unit 6. The fresh water supply unit 5 is a water storage tank (not shown) for storing fresh water. And a fresh water pump 5b.
[0008]
The mass flow meter 2 has a measuring section including an inflow pipe 2a arranged in a straight line, an outflow pipe 2b, and a bent pipe 2c arranged in the horizontal direction between these pipes. The bent pipe 2c vibrates when the liquid mixed with solid foreign matters passes through the bent pipe 2c and is discharged from the outflow pipe 2b. Further, the mass flow meter 2 has a strain amount detector 2d so as to detect a twist generated between the inflow side and the outflow side of the bent pipe 2c due to the Coriolis force generated by the vibration of the bent pipe 2c. The detected value is sent to the calculation unit 6 via an A-D conversion unit (not shown). Further, the mass flow meter 2 is provided with a pickup unit 2e for detecting the vibration of the bent pipe 2c, and the natural frequency of the bent pipe 2c is calculated by an arithmetic unit 6 via an AD converter (not shown). Configured to be sent to.
[0009]
The calculation unit 6 receives various information such as the external input / output unit 6a for inputting the strain amount of the bent pipe 2c and its natural frequency, the control unit 6b for controlling various operations, the density of fresh water, and the true specific gravity of solid foreign matters. An input unit 6c for inputting, a storage unit 6d for storing various types of information, and a display unit 6e for displaying various types of information such as mass or density are included. The input unit 6c has a mode selection switch (not shown), a work start switch (not shown), and a fresh water supply switch (not shown), a measurement mode for measuring the mass of the liquid, and when fresh water is supplied. While selecting the detection mode for measuring the density of fresh water, the main pump 7 can be operated by the work start switch in the measurement mode, and the fresh water pump 5b of the fresh water supply unit 5 can be operated by the fresh water supply switch in the detection mode. ing.
[0010]
The controller 6b controls the operation of the main pump 7 by turning on / off the work start switch to control the supply of liquid, while controlling the operation of the fresh water pump 5b by turning on / off the fresh water supply switch when the work switch is off. Thus, the supply of fresh water to the inflow pipe 2a is controlled. Further, in the measurement mode, the control unit 6b reads the detection value of the strain amount detection unit 2d at regular intervals, calculates the passing mass of the liquid from the strain amount of the bent pipe 2c, and calculates the detection value of the pickup unit 2e at regular intervals. And the mass per unit volume of the bent pipe 2c containing the liquid, the mass per unit volume of the liquid, and the density of the liquid are calculated from the natural frequency of the bent pipe 2c. Furthermore, the control unit 6b is in the detection mode.
1) Only the detection value of the pickup unit 2e is read at regular intervals.
2) From this value, the natural frequency of the bent pipe 2c, the mass per unit volume of the bent pipe 2c containing the liquid, the mass per unit volume of the liquid, and the density of the liquid are calculated.
3) The calculated density of fresh water and the density of fresh water stored in the storage unit 6d are compared, and the amount of adhering matter adhering to the inner wall surface of the bent pipe 2c is detected from the difference therebetween, and the difference is predetermined. When the value exceeds the value, a cleaning liquid supply command signal is output and a cleaning display command signal is output to the display unit 6e.
4) It is configured to be a return.
[0011]
On the other hand, the cleaning liquid supply unit 4 constituting a part of the cleaning apparatus 1 includes a cleaning liquid pipe 4a, a cleaning liquid pump 4b, and a storage tank (not shown) for storing the cleaning liquid. The cleaning liquid pump 4b is connected to the control unit 6b. It is configured to operate in response to a cleaning liquid supply command signal.
[0012]
In the mass flow meter cleaning device, when the operation start switch is turned on after the measurement mode is selected by the mode selection switch, the main pump 7 is activated and the liquid mixed with the solid foreign matter flows into the inflow pipe 2a of the mass flow meter 2. To the bent pipe 2c and the outflow pipe 2b. When the liquid passes through the bent pipe 2c of the mass flow meter 2, the bent pipe 2c vibrates, and the strain amount of the bent pipe 2c due to this vibration is detected by the strain amount detection unit 2d, and the value becomes a digital value. It is converted and sent to the external input / output unit 6 a of the calculation unit 6. The vibration of the bent pipe 2c is also detected by the pickup unit 2e, and its natural frequency is converted into a digital value and sent to the external input / output unit 6a of the arithmetic unit 6. The calculation unit 6 reads the strain amount and the natural frequency at regular intervals, and calculates the mass of the liquid from the strain amount. On the other hand, the bending including the liquid is calculated from the natural frequency and the true specific gravity of the solid foreign matter calculated in advance. The mass per unit volume of the pipe 2c, the mass per unit volume of the liquid, and the density of the liquid are calculated from this mass, and these are stored in the storage unit 6d and displayed on the display unit 6e.
[0013]
When the liquid measurement operation is completed and the mass flow meter 2 is washed with fresh water, the detection mode is selected by the mode selection switch. In this state, when the fresh water supply switch is turned on, the fresh water pump 5b is activated, and fresh water is supplied from the inflow pipe 2a of the mass flow meter 2 to each pipe. At this time, the bent pipe 2c vibrates, and the natural frequency of the vibration is detected by the pickup unit 2e, which is converted into a digital value and sent to the external input / output unit 6a of the arithmetic unit 6. The density of the liquid is calculated from this natural frequency as in the measurement mode. This density is compared with the density of fresh water (1.000) inputted in advance, and when the difference between the two becomes a predetermined value or more, a cleaning display command is sent to the display unit 6e, and a cleaning display is made on the display unit 6e. This display allows the operator to disassemble and clean the mass flow meter 2 when the cleaning liquid supply unit 4 is not connected.
[0014]
When the cleaning liquid supply unit 4 is attached, a cleaning liquid supply command signal is output simultaneously with the cleaning display command signal, the cleaning liquid pump 4b is activated, and the cleaning liquid is supplied to the inflow pipe 2a of the mass flow meter 2. The deposits adhering to the inner wall of each pipe are cleaned. This operation is repeated, so that the measurement unit of the mass flow meter 2 can be reliably cleaned.
[0015]
【The invention's effect】
As described above, the present invention calculates the density of fresh water from the vibration of the bent pipe when fresh water is supplied, and compares the density of this fresh water with the density of fresh water stored in advance. Therefore, there is an advantage that the deposit on the inner wall surface of the pipe can be reliably detected and the degree of cleaning of the inner wall surface of the pipe can be grasped numerically. In addition, since the present invention uses a cleaning liquid supply unit connected to the mass flow meter adhering matter detection device, when the adhering material exceeds a predetermined value, the cleaning liquid is supplied and the pipe is repeatedly washed. It is possible to remove the deposits on the inner wall surface of the pipe with certainty.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a mass flow meter cleaning device according to the present invention.
FIG. 2 is a schematic explanatory diagram of each pipe constituting the measurement unit of the mass flow meter according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cleaning apparatus 2 Mass flowmeter 2a Inflow pipe 2b Outflow pipe 2c Bending pipe 2d Strain amount detection part 2e Pickup part 3 Adhering substance detection apparatus 4 Cleaning liquid supply part 4a Cleaning liquid pipe 4b Cleaning liquid pump 5 Fresh water supply part 5a Fresh water pipe 5b Fresh water pump 6 Operation unit 6a External input / output unit 6b Control unit 6c Input unit 6d Storage unit 6e Display unit 7 Main pump

Claims (2)

A bent pipe is arranged between the inflow pipe and the outflow pipe arranged in a straight line, and the amount of strain of the bent pipe while the liquid mixed with solid foreign matters passes through the bent pipe and is discharged from the outflow pipe. In a mass flow meter equipped with a measurement mode that detects mass and calculates the mass of the liquid from this strain amount,
Separately from the measurement mode, an input unit for selecting the detection mode is provided, and the density of the fresh water is calculated from the natural frequency of the bent pipe when the fresh water is supplied in the detection mode. In comparison, the adhering matter detection apparatus is configured to detect the adhering amount of the adhering matter to the inner wall surface of the bent pipe from the difference between the two. A bent pipe is arranged between the inflow pipe and the outflow pipe arranged in a straight line, and the amount of strain of the bent pipe while the liquid mixed with solid foreign matters passes through the bent pipe and is discharged from the outflow pipe. In a mass flow meter equipped with a measurement mode that detects mass and calculates the mass of the liquid from this strain amount,
Separately from the measurement mode, an input unit for selecting the detection mode is provided, and the density of fresh water is calculated from the natural frequency of the bent pipe when fresh water is supplied in the detection mode, and this density is stored as the density of fresh water stored in advance. In comparison, the cleaning apparatus is configured to supply the cleaning liquid from the inflow pipe when the difference between the two becomes a predetermined value or more.

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