RU2430335C2 - Vibratory flow meter to define heat carrier flow rate in fuel channels of hpcr - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: proposed invention is intended for use in high-power channel reactors (HPCR). Proposed vibratory flow meter comprises case with inlet and outlet branch pipes, sensitive element and holder. Cylindrical sensitive element is arranged inside said case. Perforated rod-like holder is arranged coaxially inside sensitive element. Holder perforations accommodate coil with oscillation picking-up magnet and oscillation excitation magnet. Flow meter incorporates also transducer to measure oscillation damping time. Said transducer is connected to self-oscillatory circuit gate to be controlled by said gate and to amplifier and secondary instrument. Secondary instrument allows displaying heat carrier flow rate in fuel channels of HCPR. Vane-like sheet is secured to sensitive element. Oscillation pickup-up coil, oscillation excitation coil, amplifier and gate form self-oscillatory circuit.

EFFECT: higher accuracy, sensitivity and reliability, longer life.

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Description

The invention relates to measuring equipment and is intended to determine the flow rate of the coolant in the fuel channels of a high-power channel reactor (RBMK). In addition, the invention can be used in the petrochemical, food, chemical industries, thermal and nuclear energy, utilities and other industries where it is necessary to measure the flow rate of various liquid and gaseous media.

The closest analogue of the invention, taken as a prototype, is the flow meter disclosed in patent EP 0564682 A1 (IPC G01F 1/66, G01F 1/78, G01F 1/84, publ. 10/13/1993). The known flowmeter is designed to operate in aggressive environments and can be used to determine the flow rate of the coolant in the fuel channels RBMK. This flowmeter comprises a housing with inlet and outlet nozzles, a sensing element located inside the housing and made cylindrical, a holder with a vibration pickup coil and a vibration exciter coil, made in the form of a rod and placed inside the sensing element.

However, this flowmeter has disadvantages - insufficient measurement accuracy and sensitivity.

The essence of the present invention lies in the fact that the flow meter for determining the flow rate of the coolant in the RBMK fuel channels is vibrational, contains a housing with inlet and outlet nozzles, a sensing element made cylindrical and located inside the housing, and a holder made in the form of a rod with holes, coaxially placed inside the sensing element. A coil with a magnet for removing oscillations and a coil with a magnet for the exciter of vibrations are embedded in the holes in the holder. The flow meter also contains a converter configured to measure the oscillation decay time, connected to a key with the ability to control this key, and also connected to an amplifier and a secondary device. The secondary device is configured to display the magnitude of the coolant flow rate in the RBMK fuel channels. The sensing element is attached to the housing with an upper base. The holder is attached to the sensing element with the upper part. A spatula-shaped sheet is welded to the sensitive element, which is located by a face along the coolant flow with the possibility of dissecting the flow by the edge of the spatula-shaped sheet. An oscillation pickup coil, an amplifier, a key, and an oscillator exciter coil form a self-oscillating circuit.

The advantages of the invention are as follows.

Lack of moving parts.

The ability to measure flow on large diameter pipelines.

High operating temperature (up to 600 degrees).

Resistance to ionizing radiation.

Long service life (up to 30 years).

Maintainability.

Allows you to reduce the dose of ionizing radiation to staff.

The technical result of the invention is to improve the accuracy of measurement, sensitivity, reliability, as well as increasing the life of the device.

Figure 1 shows the flow meter for determining the flow rate of the coolant in the fuel channels of RBMK, figure 2 - self-oscillating circuit of the flow meter for determining the flow of the coolant in the fuel channels of RBMK. The structural elements of the flow meter for determining the flow rate of the coolant in the fuel channels of RBMK are indicated in figures 1 and 2 by the following positions: 1 - holder; 2 - coil removal oscillations; 3 - magnet removal oscillations; 4 - magnet of the pathogen; 5 - coil of the pathogen; 6 - a sensitive element; 7 - spatula-shaped sheet; 8 - locking lock; 9 - case; 10 - inlet pipe; 11 - outlet pipe; 12 - amplifier; 13 - key; 14 - converter; 15 - secondary device.

As shown in figure 1, the flow meter for determining the flow rate of the coolant in the fuel channels of the RBMK contains a housing 9 with an inlet pipe 10 located in the side of the housing 9 and an outlet pipe 11 located in the lower part of the housing 9. Inside the housing 9 is installed a sensing element 6 made in the form of a hollow vertical cylinder and attached to the housing 9 by the upper base using a flange connection. A spatula-shaped sheet 7 is welded to a part of the sensing element 6 located inside the housing 9. The spatula-shaped sheet 7 is located faceted along the coolant flow with the possibility of cutting the flow with a sheet edge. Inside the sensing element 6, a holder 1 in the form of a stainless steel rod is located coaxially with the upper part and is secured to the sensitive element 6 by means of a locking lock 8. On the holder 1, holes are cut into which an oscillation pick-up coil 2 with an oscillation pick-up magnet 3 and an exciter coil are inserted oscillations 5 with a magnet of the exciter 4.

As shown in figure 2, the oscillation pickup coil 2 is connected to the input of the amplifier 12, which is connected to the first input of the switch 13 by the first output and to the input of the converter 14. The oscillator 5 coil is connected to the output of the key 13. Thus, the coil oscillation pick-up 2, amplifier 12, key 13 and the coil of the exciter 5 form a self-oscillating circuit. The first output of the converter 14 is connected to the second input of the key 13, and the second output of the converter 14 is connected to the secondary device 15, which displays the output signal of the flow.

The flow meter for determining the flow rate of the coolant in the fuel channels RBMK works as follows.

The flow of the coolant, which is a controlled medium, enters the flowmeter through the inlet pipe 10 and is output through the outlet pipe 11. The oscillator exciter coil 5, the oscillation pick-up coil 2, the amplifier 12 are assembled into a self-oscillating circuit through a closed key 13, which is excited at a resonant frequency with this inclusion . The resonant frequency is determined by the design of the flowmeter. When vibrations occur in a self-oscillating circuit, transverse vibrations of the sensing element 6 occur. The transducer 14 is designed to control the key 13 and measure the oscillation decay time. When oscillations occur in the self-oscillating circuit, the converter 14 issues a command for switching the key 13. The key 13 opens and disconnects the coil of the pathogen 5 from the first output of the amplifier 12, while the pickup coil 2 remains connected to the input of the amplifier 12, from the second output of which the signal also comes to the input of the transducer 14. The transducer 14 calculates the damping time of the oscillations from the time the signal was issued to the key 13 and to the set vibration damping setting. Changing the decay time is directly proportional to the flow rate of the coolant. This process resumes after measuring the decay time. The value of the output signal characterizing the amount of coolant flow in the RBMK fuel channels is displayed on the secondary device 75.

The accuracy of the flow meter measurements to determine the coolant flow rate in the RBMK fuel channels is 2%, the service life is at least 10 years.

Using the proposed flow meter to determine the flow rate of the coolant in the RBMK fuel channels provides, compared with existing devices, a significant increase in the service life, lower dose loads of ionizing radiation on maintenance personnel, and increase measurement accuracy, sensitivity, and reliability.

The device is being prepared for use at RBMK NPPs to determine the coolant flow rate in technological channels.

Claims (1)

A flowmeter for determining the flow rate of the coolant in the RBMK fuel channels, comprising a housing with inlet and outlet nozzles, a sensing element made cylindrical and located inside the housing, a holder made in the form of a rod with holes coaxially placed inside the sensing element, and coils with a vibration removal magnet and a coil with a vibration exciter magnet, characterized in that the flowmeter comprises a transducer configured to measure time for vibration, connected to a key with the ability to control this key, and also connected to an amplifier and a secondary device configured to display the flow rate of the coolant in the RBMK fuel channels, while the sensitive element is attached to the housing by the upper base, the holder is attached to the sensitive element by the upper part , a shovel-like sheet is welded to the sensitive element, located facet along the coolant flow with the possibility of dissecting the flow by the edge of the shovel-like hundred, and the coil of the oscillations, the amplifier, the key and the coil of the pathogen of oscillations form a self-oscillating circuit.

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