JP3144340B2 - Vibrating gas density meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a vibrating gas density meter having a small pressure loss.

[0002]

2. Description of the Related Art FIG. 4 is a diagram for explaining the structure of a conventional example generally used in the prior art. For example, a catalog name: "DG8
Form 4 Vibro Gas Analyzer ”, date of issue; 1990
July 15, 2015, issued by Yokogawa Electric Corporation. FIG. 5 is a sectional view taken along line AA of FIG. 4, and FIGS. 6 and 7 are operation explanatory diagrams of FIG.

In FIGS. 4 and 5, reference numeral 1 denotes a central block. It is provided so that the flow rate of the measurement fluid may be small. Reference numeral 2 denotes a temperature measuring resistor for temperature compensation embedded in the center block 1. Reference numeral 3 denotes an inner cylinder in which the resistance thermometer 2 is built in a concentric shape.

[0004] Reference numeral 4 denotes an outer cylinder in which the inner cylinder 3 is concentrically housed. Reference numeral 5 denotes a thin cylindrical vibrator provided concentrically between the inner cylinder 3 and the outer cylinder 4. Reference numeral 6 denotes an excitation element that excites the cylindrical vibrator 5. In this case, a piezoelectric element is used.

[0005] Reference numeral 7 denotes a case in which the outer cylinder 4 is built. 8
Is a sleeve for fixing one end of the outer cylinder 4 to the case 7. In this case, hard Teflon is used.

Reference numeral 9 denotes a first O-ring for sealing the inner cylinder 3 and the sleeve 8. Reference numeral 11 denotes a second O-ring that seals the sleeve 8 and the outer cylinder 4. Reference numeral 12 denotes an anti-vibration rubber for fixing the other end of the outer cylinder 4 to the case 7.

Reference numeral 13 denotes a ring-shaped inner peripheral surface supply passage which is provided on the bottom portion 14 of the outer cylinder 4 and supplies a measurement fluid to the inner peripheral surface of the cylindrical vibrator 5. An outer periphery 15 is provided on the bottom portion 14 of the outer cylinder 4 and is arranged on the outer periphery of the inner peripheral surface supply path 13 so as to avoid the excitation element 6 and supplies the measurement fluid to the outer peripheral surface of the cylindrical vibrator 5. This is a surface supply hole. In this case, four are provided.

In the above configuration, as shown in FIGS. 6 and 7, the measurement gas enters the inner cylinder 3, turns back at the lower part of the inner cylinder 3, enters the bottom 14 of the outer cylinder 4, and enters the inner peripheral surface supply path 13. And the outer peripheral surface supply hole 15. It passes through the inner and outer peripheral surfaces of the cylindrical vibrator 5 and comes out of the outer cylinder 4.

Thus, the resonance frequency of the cylindrical vibrator 5 becomes
Utilizing that it changes depending on the gas density around the cylinder,
The density of the measurement gas fluid is measured by measuring the resonance frequency of the cylindrical vibrator 5.

[0010]

However, in such an apparatus, (1) four outer peripheral surface supply holes 15 are provided on the outer circumference of the inner peripheral surface supply passage 13; In an attempt to develop a more sensitive vibration type gas density meter, it has been found that the stagnation portion of the measurement fluid generated between each of the four outer peripheral surface supply holes 15 adversely affects the response characteristics of the cylindrical vibrator 5. I've been. (2) The inlet and outlet of the measurement gas are provided close to each other, assuming that they are directly inserted into the measurement pipe. However, the flow path of the measurement fluid is turned back, and the pressure loss increases.
When the pressure loss increases, the measurement fluid used for the density measurement is disposed of, for example, being discharged into the atmosphere as exhaust gas due to a decrease in pressure, which is against the trend of global environmental protection in recent years. Further, in order to obtain effective temperature compensation by detecting the temperature of the resistance temperature detector 2, the flow path of the measurement fluid is made longer corresponding to the length of the resistance temperature detector 2, but this length is also a pressure loss. Cause (3) Central block 1, inner cylinder 3, cylindrical vibrator 5, and outer cylinder 4
Are assembled concentrically, the structure is complicated, and the processing and assembly costs are high.

The present invention solves these problems. An object of the present invention is to provide a vibrating gas density meter having improved sensitivity and reduced pressure loss.

[0012]

In order to achieve this object, the present invention provides a cylindrical vibrator and one end of the cylindrical vibrator fixed to the bottom on one end side, and the cylindrical vibrator is built in a concentric shape. A cylindrical body, an excitation element provided at the bottom of the cylindrical body to excite the cylindrical vibrator, and a ring provided at the bottom of the cylindrical body to supply a measurement fluid to the inner peripheral surface of the cylindrical vibrator Shaped internal peripheral surface supply path, and provided at the bottom of the cylindrical body main body, on the outer circumference of the internal peripheral surface supply path, arranged so as to avoid the excitation element, and the measurement fluid to the external peripheral surface of the cylindrical vibrator. A vibrating gas density meter, comprising: an outer peripheral surface supply hole for supplying; and a case in which both ends of the cylindrical body are supported and the cylindrical body is built in concentrically, a cylinder provided at the bottom of the cylindrical body. A stagnation part of the measurement fluid occurs when the measurement fluid is supplied to the outer peripheral surface of the vibrator A predetermined number of outer peripheral surface supply holes, and one end provided in the case on the bottom side of the cylindrical body, and the other end communicating with the inner peripheral surface supply passage and the predetermined number of outer peripheral surface supply holes. A measurement fluid introduction passage into which the measurement fluid is introduced, and a measurement in which one end is provided in the case on the other end side of the cylindrical body and the other end is communicated with the other end side of the cylindrical body to discharge the measurement fluid. A vibratory gas density meter comprising a fluid discharge path is provided.

[0013]

In the above construction, the measurement fluid enters the cylinder body through the measurement fluid introduction passage, branches into the inner peripheral surface supply passage and a predetermined number of outer peripheral surface supply holes, and passes through the inner and outer peripheral surfaces of the cylindrical vibrator. hand,
It is discharged from the measurement fluid discharge path. Thus, utilizing the fact that the resonance frequency of the cylindrical vibrator changes depending on the gas density around the cylinder, the resonance frequency of the cylindrical vibrator can be measured to measure the density of the measurement gas fluid. Hereinafter, a detailed description will be given based on embodiments.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a main part of an embodiment of the present invention, FIG. 2 is a detailed explanatory view of a main part of FIG. 1, and FIG. 3 is a sectional view taken along the line BB of FIG. In the figure, the configuration of the same symbol as FIG. 4 represents the same function. Hereinafter, only differences from FIG. 4 will be described.

Reference numeral 21 denotes a cylindrical main body in which one end of the cylindrical vibrator 5 is fixed to a bottom portion 22 on one end side, and the cylindrical vibrator 5 is built in concentrically. Reference numeral 23 denotes an outer peripheral surface supply hole provided on the bottom portion 22 of the cylindrical main body and provided with a predetermined number so that a stagnant portion of the measurement fluid is not generated when the measurement fluid is supplied to the outer peripheral surface of the cylindrical vibrator 5. It is. In this case, eight outer peripheral surface supply holes 23 are provided.

Reference numeral 24 denotes a case 7 on the bottom 22 side of the cylindrical body.
Is provided with one end, and the other end is connected to the inner peripheral surface supply passage 13 and a predetermined number of outer peripheral surface supply holes 23 to be a measurement fluid introduction passage through which a measurement fluid is introduced. 25 is provided with one end on the case 7 on the other end side of the cylindrical body 21 and the other end on the cylindrical body 21.
Is a measurement fluid discharge passage that communicates with the other end of the measurement fluid and discharges the measurement fluid.

In the above configuration, as shown in FIG. 1, the measurement fluid enters the cylinder main body 21 through the measurement fluid introduction passage 24 and branches into the inner peripheral surface supply passage 13 and the eight outer peripheral surface supply holes 23. Then, it passes through the inner and outer peripheral surfaces of the cylindrical vibrator 5 and exits from the measurement fluid discharge passage 25.

Thus, the resonance frequency of the cylindrical vibrator 5 becomes
Utilizing that it changes depending on the gas density around the cylinder,
By measuring the resonance frequency of the cylindrical vibrator 5, the density of the measurement gas fluid can be measured.

As a result, (1) the outer peripheral surface supply hole 23 is provided in the bottom portion 22 of the cylindrical body, and when the measuring fluid is supplied to the outer peripheral surface of the cylindrical vibrator 5, a stagnation portion of the measurement fluid is generated. Since the predetermined number is set so as not to be contaminated, contamination of the measurement fluid can be eliminated, response characteristics can be improved, and a highly sensitive vibrating gas density meter can be obtained.

(2) The measurement gas inlet and outlet are not provided close to each other so that they can be directly inserted into the measurement pipe, and a measurement fluid introduction passage 24 is provided at one end of the cylindrical body 21. Since the measurement fluid discharge passage 25 is provided on the other end side and the return of the flow passage of the measurement fluid is eliminated, the flow passage resistance is reduced and the pressure loss is reduced. Further, since a predetermined number of outer peripheral surface supply holes 23 are provided so as not to generate a stagnation portion of the measurement fluid, the pressure loss is further reduced.

For this reason, it is possible to measure even if the differential pressure between the input and output of the vibrating gas density meter is small, and the vibrating gas density meter can be arranged in the circulating system to be measured.
This eliminates the need for a special sampling device, and provides a vibrating gas density meter that can reduce installation costs.

In particular, a vibrating gas density meter suitable for measuring a dangerous measuring fluid such as a hydrogen concentration measurement in a hydrogen-cooled generator can be obtained.

(3) Furthermore, since the pressure loss is small and the pressure difference between the input and output of the vibrating gas density meter can be measured even if it is small, the fluid to be measured at the output portion of the vibrating gas density meter is Since there is no need to reduce the pressure, it is easy to return the measured fluid to a reusable part.
There is no need to discharge and dispose as exhaust gas to the atmosphere, which meets recent trends in the protection of the global environment, and a vibrating gas density meter that can reduce the use cost can be obtained.

Particularly, for example, a vibrating gas density meter suitable for, for example, returning the measured LNG to the sampling source line in the LNG calorific value adjustment line in the city gas industry is obtained.

[0025]

As described in detail above, according to the present invention, (1) an outer peripheral surface supply hole is provided at the bottom of the cylindrical body to supply the measurement fluid to the outer peripheral surface of the cylindrical vibrator. At this time, since a predetermined number is provided so that the stagnation portion of the measurement fluid does not occur,
The contamination of the measurement fluid can be eliminated, the response characteristics can be improved, and a highly sensitive vibrating gas density meter can be obtained.

(2) The inlet and outlet of the measurement gas are not provided close to each other so that they can be directly inserted into the measurement pipe, and a measurement fluid introduction path is provided at one end of the cylindrical body, and the other end is provided. Since the measurement fluid discharge path is provided on the side and the return of the flow path of the measurement fluid is eliminated, the flow path resistance is reduced and the pressure loss is reduced. Further, since a predetermined number of outer peripheral surface supply holes are provided so as not to generate a stagnation portion of the measurement fluid, pressure loss is further reduced.

For this reason, it is possible to measure even if the differential pressure between the input and output of the vibrating gas density meter is small, and the vibrating gas density meter can be arranged in the circulating system to be measured.
This eliminates the need for a special sampling device, and provides a vibrating gas density meter that can reduce installation costs.

In particular, a vibrating gas density meter suitable for measuring a dangerous measuring fluid such as a hydrogen concentration measurement in a hydrogen-cooled generator can be obtained.

(3) Further, since the pressure loss is small and the pressure can be measured even when the differential pressure between the input and output of the vibrating gas density meter is small, the fluid to be measured at the output portion of the vibrating gas density meter is Since there is no need to reduce the pressure, it is easy to return the measured fluid to a reusable part.
There is no need to discharge and dispose as exhaust gas to the atmosphere, which meets recent trends in the protection of the global environment, and a vibrating gas density meter that can reduce the use cost can be obtained.

In particular, for example, a vibration type gas density meter suitable for returning the measured LNG to the line from which the LNG was collected in the LNG calorific value adjustment line in the city gas industry can be obtained.

Therefore, according to the present invention, it is possible to realize a vibration-type gas density meter with improved sensitivity and reduced pressure loss.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a configuration of an embodiment of the present invention.

FIG. 2 is a detailed view of a main part of FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is an explanatory diagram of a configuration of a conventional example generally used in the related art.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is an operation explanatory diagram of FIG. 4;

FIG. 7 is an explanatory view of the operation principle of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Central block 2 Resistance temperature detector 5 Cylindrical vibrator 6 Exciting element 7 Case 13 Inner peripheral surface supply path 21 Cylindrical body 22 Bottom 23 Outer peripheral surface supply path 24 Measurement fluid introduction path 25 Measurement fluid discharge path

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ryuichi Kawamura 2-9-132 Nakamachi, Musashino City, Tokyo Inside Yokogawa Electric Corporation (56) References JP-A-4-296635 (JP, A) JP-A Sho 64-84132 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 9/00 JICST file (JOIS)

Claims (1)

(57) [Claims] A cylindrical vibrator; one end of the cylindrical vibrator fixed to a bottom on one end side; a cylindrical main body in which the cylindrical vibrator is concentrically housed; and a cylindrical main body provided at a bottom of the cylindrical main body. An excitation element that excites the cylindrical vibrator; a ring-shaped inner peripheral surface supply path that is provided at the bottom of the cylindrical main body and supplies a measurement fluid to the inner peripheral surface of the cylindrical vibrator; An outer peripheral surface supply hole provided on the outer circumference of the inner peripheral surface supply path so as to avoid the excitation element and supplying a measurement fluid to the outer peripheral surface of the cylindrical vibrator; and both ends of the cylindrical main body are supported. And a case in which the cylindrical body is concentrically housed, wherein the measuring fluid is provided at the bottom of the cylindrical body when the measuring fluid is supplied to the outer peripheral surface of the cylindrical vibrator. An outer peripheral surface supply hole provided with a predetermined number so that no stagnation portion is generated; A measurement fluid introduction path through which one end is provided in the case on the bottom side of the cylindrical body and the other end is communicated with the inner peripheral surface supply path and the predetermined number of outer peripheral surface supply holes and a measurement fluid is introduced; A vibrating gas, comprising: a measurement fluid discharge path through which one end is provided in the case on the other end side of the body main body and the other end communicates with the other end side of the cylindrical body main body to discharge a measurement fluid. Densitometer.