JPH04339220A - Coriolis type mass flowmeter - Google Patents

Abstract

PURPOSE:To achieve a reduction in cost of filling by a method wherein a plurality of vibration pipes are driven between a pair of support members and a mass flow rate of a fluid is measured from a Coriolis force generated in the vibration pipes to correct the mass flowrate passing through a plurality of passages with a back pressure adjusting unit. CONSTITUTION:U-shaped conduits 3a and 3b equal in shape and dimensions are supported with support members 4 and 5 and a filling liquid flowing through a flow tube 1 is shunted within the member 4 and then, to shunt tubes 1a and 1b through the conduits 3a and 3b. The conduits 3a and 3b are driven at a fixed amplitude with a mass flow rate converter 7 through a driver and a detector 6, speeds of arm parts of the conduits 3a and 3b are detected with detectors at parts B and C and a Coriolis force is detected with the converter 7 as time difference in the passage of the arm parts through a reference surface to be converted into a mass flow rate. A mass flow rate signal is transmitted to a built-in batch unit 8 and a valve 2 is closed when the mass flow rate reaches a set value. Filling containers 11a and 11b are filled with a filling liquid having a pressure loss adjusted constant with back pressure flow rate adjusting units 9a and 9b.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mass flowmeter used for filling fluids, and more particularly to a Coriolis mass flowmeter that allows a plurality of fluids to be filled simultaneously using one mass flowmeter.

0002

BACKGROUND OF THE INVENTION Fluid filling, particularly liquid filling, is a necessary step for liquid transportation, and as the products and markets become more diverse, containers come in many different shapes and sizes. There is also a call for rationalization of filling, and there is a need for a filling machine that can perform filling quickly, at low cost, and with high precision.

Conventionally, when filling a liquid, a force meter is usually used as a weighing device, and the amount of filling is measured by weight. As a force meter, a load cell using a strain gauge or a platform scale is used.A load cell uses an elastic body as a pressure receiving part to measure the amount of strain, and a platform scale detects the balance of a lever. In either case, it takes time to detect the deflection of the object to be measured after the force is balanced, and these methods are unsuitable for rapid measurement.

[0004] Flowmeters measure the volumetric flow rate flowing through pipes, and close valves based on the readings from the flowmeter, so they have excellent responsiveness, but mass flowmeters, like the force meters mentioned above, have particularly good response. It has a feature that the force meter mentioned above does not have in that it can perform measurements.

[0005] Examples of mass flowmeters include Coriolis mass flowmeters that utilize Coriolis force. Many shapes of Coriolis mass flowmeters are used, but basically, when a flow tube is supported at two points and the flow tube is vibrated between the support positions, the Coriolis force is This takes advantage of the fact that it occurs in the vector product direction with the fluid flow and is proportional to the mass flow rate.

Typical Coriolis mass flowmeters include:
A U of the same shape and size with an inlet and an outlet using the flow tube as a support point.
The U-shaped conduits are arranged in parallel, and the inlet and outlet of the U-shaped conduit of the flow tube are closed so that an equal amount of fluid to be measured flows through each of the U-shaped conduits arranged in parallel. Then, the U-shaped conduit is vibrated so that the flow tube and the U-shaped conduit vibrate like a tuning fork, and the arms of the U-shaped conduit absorb the Coriolis force generated around the U-shaped conduit axis perpendicular to the flow tube. The time difference in passing through the reference plane is measured, and the mass flow rate is measured from the Coriolis force.

[0007] The Coriolis mass flowmeter is composed of a pair of U-shaped conduits that form a tuning fork, but the conduit is not limited to a U-shaped conduit, and in many cases, whether it is a true tube or an S-shaped conduit, resonance occurs. It consists of two flow tubes that form a pair to utilize the flow.

When the Coriolis mass flowmeter described above is used for filling, the same fluid flowing through the flow tube is passed through the pair of conduits constituting the Coriolis mass flowmeter and the Coriolis force is measured, and then the Coriolis force is measured. Since a method is adopted in which the flow is returned to the discharge side flow pipe, one mass flowmeter with the above configuration is required to fill one container, and when filling multiple containers,
The same number of mass flow meters was required.

FIG. 3 is a diagram for explaining a conventional filling system, in which 21 is a flow tube, 22 is a branch tube, 23, 24
26, 27, 29, 30 are support members, 25,
28 is a Coriolis mass flowmeter, 25a, 25b, 28a
, 28b is a U-shaped conduit, 31 and 32 are drive and detectors, 3
3, 34 are mass converters, 35, 36 are batch units for preparation, 37, 38 are control valves, 39, 40 are discharge pipes, 41
, 42 is a filling container, 41a, 42a are filling ports, 43a,
43b, 43c, 44a, 44b, and 44c are conducting wires.

The illustrated filling system is for carrying out two series of filling. The liquid to be filled passes through the flow pipe 21 and is divided into approximately equal flow rates by the branch pipe 22 and sent to the branch pipes 23 and 24. The divided liquids to be filled are measured by Coriolis mass flowmeters 25 and 28, respectively. Coriolis mass flowmeter 2
5 has a structure in which U-shaped conduits 25a and 25b of the same shape and size are supported in parallel by a support member 26 on the inflow side and a support member 27 on the outflow side, and the liquid to be filled is transferred to the U-shaped conduits on the support member 26 side. 25a and 25b so that the flow is approximately equal, and then merges again on the support member 27 side and flows out into the branch pipe 23.

The U-shaped conduits 25a and 25b are driven by a drive and detector 31 by resonant vibrations in the directions of approaching and repulsing each other with respect to the support members 26 and 27, and the mass transducer 3
3, the mass flow rate is detected by determining the Coriolis force as the time difference in passing the reference plane of the U-shaped conduits 25a and 25b. The mass flow signal is transmitted to the batch unit 35 by conductors 43a,b. The batch unit 35 for preparation is a setting device that presets the filling mass to be filled into the filling container 41, and when the set value is reached, the control valve 37 is closed and the transfer of the filling liquid to the discharge pipe is stopped.
Preparing for the next filling.

Similarly to the above, the Coriolis mass flowmeter 28 measures the mass flow rate of the liquid to be filled which has been branched into the branch pipe 24, and when the amount reaches the amount set in the batch unit 36 for preparation, the control valve 38 closes and the filling container is closed. 42 is stopped.

As mentioned above, according to the conventional method, a mass converter and a batch unit for preparation are required for each mass flow meter, so as the number of filling systems increases, the filling equipment becomes more expensive. It became. In addition, in order to reduce the cost of the filling device, there is a method, for example, of installing an outlet selection valve downstream of one mass flowmeter and filling the A line and B line alternately in a time-sharing manner, but the filling capacity is only for one car.

[0014]

[Purpose] The present invention was made in view of the above-mentioned circumstances, and uses one Coriolis mass flowmeter for a plurality of containers, and one of the conduits constituting the Coriolis mass flowmeter. , which fills a single container, takes advantage of the flow meter method's superiority in response to filling operations over the force meter method, and enables inexpensive filling equipment without reducing measurement accuracy. The object of the present invention is to provide a Coriolis mass flowmeter that provides a Coriolis mass flowmeter.

[0015]

[Structure] In order to achieve the above objects, the present invention provides (1)
In a flow path that branches a fluid flow into a plurality of flow paths and discharges the fluid by equalizing the mass flow rate of each of the branched flow paths, a plurality of Consisting of vibrating tubes of the same shape and a back pressure adjustment unit connected in series to each of the vibrating tubes, the plurality of vibrating tubes are driven at the same frequency and constant amplitude between a pair of support members, and the vibrating tubes are (2) measuring the mass flow rate of the fluid from the Coriolis force generated in the flow path, and correcting the mass flow rate flowing through each of the plurality of flow paths using the back pressure adjustment unit to make the mass flow rate equal; The adjustment unit is an orifice, and a flow rate adjustment hole is provided in the orifice;
3) The back pressure adjustment unit has a plurality of small-diameter channels arranged side by side in the flow direction, and (4) The back pressure adjustment unit and the discharge port are connected so that the length and/or diameter of the piping is variable. This is characterized by fine adjustment of back pressure, and will be explained below based on embodiments of the present invention.

FIG. 1 is a block diagram for explaining the outline of the present invention, in which 1 is a flow tube, 1a and 1b are branch tubes, and 2 is a block diagram for explaining the outline of the present invention.
is a control valve, 3 is a Coriolis mass flowmeter, 4 and 5 are support members, 6 is a drive and detector, 7 is a mass flow rate converter, 8 is a batch unit for preparation, 9a and 9b are back pressure flow rate adjustment units, 10a and 10b are discharge pipes, and 11a and 11b are filling containers.

The Coriolis mass flowmeter 3 has the same shape and size as U.
The shape-shaped conduits 3a and 3b are arranged in parallel with a slight distance between them, and are supported by an upstream support member 4 and a downstream support member 5, respectively, so that the liquid to be filled flowing through the flow tube 1 is approximately equally distributed within the support member 4. The liquid to be filled flows into the U-shaped conduits 3a and 3b, and the divided liquid flows into the branch pipes 1a and 1b without merging.

The U-shaped conduits 3a and 3b are driven by a drive and a detector 6 to generate vibrations that repel each other in close proximity to each other at a portion A shown in the figure.The U-shaped conduits 3a and 3b are connected to a mass flow rate converter at a resonant frequency formed by a tuning fork-like structure formed by support members 4 and 5. 7 with a constant amplitude, the speeds of the arms of the U-shaped conduits 3a and 3b are detected by the detectors provided in the B and C parts, and the mass flow converter 7 detects the velocity of the arm parts from the reference plane based on the speed signal. The Coriolis force is detected as the time difference passing through the sensor and converted to mass flow rate.

The mass flow rate signal is transmitted to the batch unit 8 for preparation, and the control valve 2 is closed when the mass flow rate reaches a set value. Since the U-shaped conduits 3a and 3b are of the same shape and size, it is expected that the filling liquid divided into each will have an equal mass flow rate, but in reality this is somewhat different.

The back pressure flow rate adjustment units 9a, 9b adjust the pressure loss at a constant level between the flow branched from the flow pipe 1 at the support member 4 on the upstream side and the flow reaching the back pressure flow rate adjustment units 9a, 9b. This is to make the mass flow rate.

FIGS. 2(a) and 2(b) are diagrams showing the structure of the back pressure flow rate adjustment units 9a, 9b, with FIG. 2(a) showing an orifice and FIG. 2(b) showing a multiple pipe.

In Figure (a), 12 is an orifice;
a is an opening, and 13 is an adjustment hole. When used as the back pressure flow rate adjustment units 9a and 9b, the openings 12a are selected to have the same diameter and the pressure loss is equal, and the diameter of the adjustment hole 13 is adjusted so that the pressure loss resulting in equal mass flow rate is obtained.

In the multiple pipe shown in FIG. 3(b), reference numeral 14 is a multiple pipe having a length L3, and a large number of pores 15 penetrate in the axial direction, so that a pressure loss proportional to the length can be obtained in the length direction. The pressure drop is adjusted by adjusting the length ΔL or by closing one or more of the pores 15.

As mentioned above, the mass flow rate in each of the branch pipes 1a, 1b is adjusted to be constant, and the mass flow rate in each of the flow pipes 10a, 1b is
The filling containers 11a and 11b are filled from 0b, respectively.
If the same mass flow rate cannot be obtained even with the above adjustments, an adapter (not shown) may be provided to connect the discharge pipes 10a and 10b.
The same mass flow rate can be obtained by adjusting the differential pressure slightly by changing the lengths L1 and L2 or by slightly changing the pipe diameter.

As mentioned above, by keeping the mass flow rate divided into each of the pair of resonantly driven U-shaped conduits 3a and 3b constant, it is possible to divide the flow into two equal mass flow rates with one mass flowmeter. Can fill two cars.

[0026] The above has been explained in the case of two U-shaped conduits 3a and 3b, but if they are arranged in parallel, it is possible to divide the flow of four lines with one driving device, and furthermore, it is possible to divide the flow of four lines with one drive device, and even an even number of lines such as 6...8. It is possible to divide the flow into equal parts.

In the above description, a U-shaped conduit has been mentioned, but the present invention is not limited to a U-shaped conduit, and can be applied to a Coriolis mass flowmeter made of a straight tube, an S-shaped tube, or the like.

[0028]

[Effect] As is clear from the above explanation, according to the Coriolis flowmeter of the present invention, multiple filling containers can be filled simultaneously with a single mass flowmeter, which is a characteristic feature of a mass flowmeter. It is possible to provide a Coriolis mass meter that allows quick filling at low cost without sacrificing accuracy.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining an overview of the present invention.

FIGS. 2(a) and 2(b) are diagrams showing the structure of a back pressure flow rate adjustment unit; FIG. 2(a) shows an orifice, and FIG. 2(b) shows a multiple pipe.

FIG. 3 is a diagram for explaining a conventional filling system.

[Explanation of symbols]

1 Flow tube 1a, 1b Diversion pipe 2 Control valve 3 Coriolis mass flowmeter 3a, 3b U-shaped conduits of the same shape and size 4,5 Support member 6 Drive and detector 7 Mass flow converter 8 Batch unit for preparation 9a, 9b Back pressure flow adjustment unit 10a, 10b Discharge pipe 11a, 11b Filling container

Claims (4)

[Claims] Claim 1: In a flow path in which a fluid flow is branched into a plurality of flow paths and the mass flow rate of each branched flow path is equalized and discharged, the plurality of flow paths are connected between a pair of common support members. consisting of a plurality of supported vibrating tubes of the same shape and a back pressure adjustment unit connected in series to each of the vibrating tubes, driving the plurality of vibrating tubes at the same frequency and constant amplitude between a pair of support members, A Coriolis device characterized in that the mass flow rate of the fluid is measured from the Coriolis force generated in the vibrating tube by driving, and the mass flow rate flowing through each of the plurality of flow channels is corrected by the back pressure adjustment unit to equalize the mass flow rate. type mass flowmeter. 2. The Coriolis mass flowmeter according to claim 1, wherein the back pressure adjustment unit is an orifice, and the orifice is provided with a flow rate adjustment hole. 3. The Coriolis mass flowmeter according to claim 1, wherein the back pressure adjustment unit has a plurality of small diameter channels arranged side by side in the flow direction. 4. The Coriolis mass flowmeter according to claim 1, wherein the back pressure is finely adjusted by connecting the back pressure adjustment unit and the discharge port with variable piping length and/or diameter. .