A high-pressure blow-off mass flow meter based on gas cylinder pressure

Abstract

The present invention relates to the field of high-pressure air mass flowmeters, and provides a high-pressure blowing mass flowmeter based on gas cylinder pressure, which is used to measure the air mass flow of a high-pressure blowing system. The device includes a high-pressure air bottle head, a pressure sensor, a temperature sensor, a pressure-resistant and waterproof protective cover shell, a watertight and pressure-resistant cable connector, a display operation panel, a sampling board, a computing and processing board, a storage and output module, and a gas cylinder outlet connector. When the high-pressure air system supplies air to the user, the air mass flow is calculated using the measured air temperature and pressure signals. The high-pressure blowing mass flowmeter based on gas cylinder pressure of the present invention is used for a high-pressure blowing system with multiple outlets for simultaneous blowing, can measure the total blowing mass flow in real time and with high precision, and can also withstand seawater corrosion and seawater pressure.

Description

Technical Field

[0001] The invention relates to the field of high-pressure blowing mass flowmeters, in particular to a high-pressure blowing mass flowmeter based on gas cylinder pressure. Background Art

[0002] Accurate measurement of high-pressure blow-off mass flow is an industry problem. Compared with low-pressure and low-speed gas, water medium, etc., high-pressure air expands violently during the flow process, resulting in its density being unstable. Various flow meters developed based on the premise of constant medium density, such as turbine flow meters, vortex flow meters, Roots flow meters, and thermal sensitive temperature flow meters, cannot be used for high-pressure air mass flow measurement.

[0003] The current commercial high-pressure air mass flowmeters are all based on the Coriolis force principle, such as the RHM 30 air mass flowmeter of Germany's RHEONIK company and the DMF mass flowmeter of Beijing Shouke Shihua Automation Equipment Co., Ltd. The measurement principle is to convert and measure the Coriolis force generated when high-pressure air flows through a specific pipe to deduce the mass flow of high-pressure air. The mass flowmeter designed based on this principle is characterized by the need for two tennis racket-shaped annular pipes for generating Coriolis force. The size of the annular pipe is 100 to 400 times the diameter of the measured pipe. This type of mass flowmeter generally takes up a large space, resulting in its overall size and weight being too large. It is mainly used in laboratories and other places that are not sensitive to space requirements, and is not suitable for use in ship water tank high-pressure blowdown pipes. This type of sensor uses mechanical methods for measurement, is sensitive to external vibration and impact, and does not meet the requirements of ship environments. In addition, in order to avoid the impact of vibration and shock in the environment, this type of sensor needs to perform time-averaged processing on the measurement data, resulting in a delay of 1 to 2 seconds in the mass flow measured in actual use, which cannot meet the precise closed-loop control requirements of the high-pressure blowing process that lasts only a few seconds. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the aforementioned prior art, to solve the problems of miniaturization, impact resistance, and rapid response of high-pressure air mass flowmeters, and to create conditions for the application of high-pressure air mass flowmeters on board ships. The present invention proposes a high-pressure blow-off mass flowmeter based on gas cylinder pressure, which is used in a high-pressure blow-off system with multiple outlets for simultaneous blowing. It can measure the total blow-off mass flow in real time and with high precision, and can also withstand seawater corrosion and seawater pressure. It is particularly suitable for real-time online measurement of the total flow of short-term and large-flow high-pressure blow-off.

[0005] The object of the present invention is achieved through the following technical solutions.

[0006] A high-pressure blowing mass flowmeter based on gas cylinder pressure includes a high-pressure air cylinder head, a pressure sensor, a temperature sensor, a pressure-resistant and waterproof protective cover shell, a watertight and pressure-resistant cable connector, a display operation panel, a sampling board, a computing and processing board, a storage and output module, and a gas cylinder outlet connector. The high-pressure air cylinder head is installed on the end of the high-pressure air cylinder and is connected to the high-pressure air cylinder by threads. The pressure sensor is installed on the high-pressure air cylinder head to measure the static pressure in the gas cylinder. The temperature sensor is installed on the high-pressure air cylinder head. The pressure-resistant and waterproof protective cover shell covers the outside of the pressure sensor and the temperature sensor and is installed on the high-pressure air cylinder head by threads. The watertight and pressure-resistant cable connector is installed on the tail of the pressure-resistant and waterproof protective cover shell. The data measured by the pressure sensor and the temperature sensor are acquired by the acquisition board and sent to the computing and processing board for computing and processing. The computing and processing board displays the calculation results in real time on the display operation panel and sends them to the storage and output module. The storage and output module is provided with an Ethernet interface.

[0007] In the above technical solution, the display operation panel, sampling board, calculation processing board, storage and output module are integrated into a secondary instrument box.

[0008] In the above technical solution, the computing processing board adopts the following steps to perform calculation:

[0009] S1, calculate the total volume V of the high-pressure air system based on the volume of each gas cylinder in the system, in m 3 ;

[0010] S2, before high-pressure blowing, calculate the temperature T0 of the high-pressure air in the gas cylinder according to the measured values ​​of the pressure sensor and the temperature sensor, the unit is K, the pressure P0 of the high-pressure air in the gas cylinder, the unit is MPa, and the high-pressure air density R0 in the gas cylinder is calculated by interpolation method from the high-pressure air density table, the unit is kg / m 3 ;

[0011] S3, after the high-pressure blowing starts, the cylinder pressure P1 during the blowing process is calculated by the measured value of the pressure sensor, the unit is MPa, and the gas temperature T1 at the corresponding moment is calculated by the formula, the unit is K, T1 = T0*(P1 / P0) 2 / 7 ;

[0012] S4, using the air temperature T1 and the air static pressure P1, look up the high-pressure air density table and calculate the air density R1 by interpolation;

[0013] S5, calculate the rate of change of high pressure air density over time by interpolation method,

[0014] dR1=(R1-R1') / dt;

[0015] S6. Calculate the mass flow rate Q of the air based on the total volume V of the high-pressure air system and the rate of change dR1 of the high-pressure air density over time. Q = V × dR1.

[0016] The high-pressure blow-off mass flowmeter based on the cylinder pressure of the present invention fundamentally changes the working principle of the high-pressure air mass flowmeter. It can not only measure the flow of large-flow high-pressure air with drastic density changes, but also circumvent the special requirements of the Coriolis force method on the measurement pipeline structure, so that the structure of the high-pressure air mass flowmeter is simplified, and the volume and weight are greatly reduced. It can be used in space-sensitive measurement occasions such as ship water tank high-pressure blow-off pipelines, especially in applications where the total mass flow of high-pressure blow-off needs to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of an embodiment of a high-pressure blow-off mass flow meter based on gas cylinder pressure of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0019] like Figure 1As shown, an embodiment of the present invention provides a high-pressure blowing mass flowmeter based on gas cylinder pressure, including a high-pressure air cylinder 1, a high-pressure air cylinder head 2, a pressure sensor 3, a temperature sensor 4, a pressure-resistant and waterproof protective cover shell 5, an O-ring 6, a watertight and pressure-resistant cable connector 7, a display operation panel 8, a sampling board 9, a computing and processing board 10, a storage and output module 11, and a gas cylinder outlet connector 12. The outlet of the high-pressure air cylinder 1 faces downward to avoid water accumulation in the gas cylinder. The high-pressure air cylinder head 2 is installed at the end of the high-pressure air cylinder, connected to the high-pressure air cylinder 1 by threads, and sealed by a copper sealing gasket. The pressure sensor 3 is installed on the high-pressure air cylinder head 2 by threads, sealed by a copper gasket, and measures the static pressure in the gas cylinder. The response time is less than 0.1ms, and the measurement range is 0.1MPa to 20MPa. The temperature sensor 4 is installed on the high-pressure air cylinder head 2 by threads and sealed by a copper gasket. The pressure-resistant and waterproof protective cover shell 5 is installed on the high-pressure air cylinder head 2 by threads and sealed by an O-ring 6. The watertight pressure-resistant cable connector 7 is installed at the tail of the pressure-resistant and waterproof protective cover shell 5 to provide a watertight cable channel. The display operation panel 8, sampling board 9, computing and processing board 10, and storage and output module 11 are integrated into a secondary instrument box. The response time of the temperature sensor 4 is greater than 1s, the measurement range is -50℃~100℃, the resolution is 0.1℃, and the length of its probe is 30~50mm longer than the height of the high-pressure air bottle head 2. The acquisition frequency of the sampling board is not less than 5000Hz. The data measured by the pressure sensor 3 and the temperature sensor 4 are acquired by the acquisition board 9 and sent to the computing and processing board 10 for calculation and processing. The computing and processing board 10 displays the calculation results in real time on the display operation panel 8 and sends them to the storage and output module 11. The storage and output module 11 is provided with an Ethernet interface. The gas cylinder outlet connector 12 is located at the bottom of the high-pressure air bottle 1, and is connected to the high-pressure air bottle 1 by threads and sealed by a copper sealing gasket.

[0020] In the above embodiment, the high-pressure air bottle 1, the high-pressure air bottle head 2, the pressure-resistant and waterproof protective cover shell 5, and the gas bottle outlet connector 12 are all made of titanium alloy material and are surface passivated to withstand seawater corrosion and seawater pressure.

[0021] In the above embodiment, the computing processing board 10 performs the calculation by using the following steps:

[0022] S1, calculate the total volume V of the high-pressure air system based on the volume of each gas cylinder in the system, in m 3 ;

[0023] S2, before high-pressure blowing, calculate the temperature T0 of the high-pressure air in the gas cylinder according to the measured values ​​of the pressure sensor 3 and the temperature sensor 4, the unit is K, the pressure P0 of the high-pressure air in the gas cylinder, the unit is MPa, and the high-pressure air density R0 in the gas cylinder is calculated by interpolation method by checking the high-pressure air density table, the unit is kg / m 3 ;

[0024] S3, after the high-pressure blowing starts, the cylinder pressure P1 during the blowing process is calculated by the measured value of the pressure sensor 4, the unit is MPa, and the gas temperature T1 at the corresponding moment is calculated by the formula, the unit is K, T1 = T0*(P1 / P0) 2 / 7 ;

[0025] S4, using the air temperature T1 and the air static pressure P1, look up the high-pressure air density table and calculate the air density R1 by interpolation;

[0026] S5, calculate the rate of change of high pressure air density over time by interpolation method,

[0027] dR1=(R1-R1') / dt;

[0028] S6. Calculate the mass flow rate Q of the air based on the total volume V of the high-pressure air system and the rate of change dR1 of the high-pressure air density over time. Q = V × dR1.

[0029] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0030] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high pressure blow-off mass flow meter based on gas cylinder pressure, Features: It includes a high-pressure air bottle head, a pressure sensor, a temperature sensor, a pressure-resistant and waterproof protective cover shell, a watertight and pressure-resistant cable connector, a display operation panel, a sampling board, a computing and processing board, a storage and output module, and a gas cylinder outlet connector. The high-pressure air bottle head is installed at the end of the high-pressure air bottle and is connected to the high-pressure air bottle by threads. The pressure sensor is installed on the high-pressure air bottle head to measure the static pressure in the gas cylinder. The temperature sensor is installed on the high-pressure air bottle head. The pressure-resistant and waterproof protective cover shell covers the outside of the pressure sensor and the temperature sensor and is installed on the high-pressure air bottle head by threads. The watertight and pressure-resistant cable connector is installed at the tail of the pressure-resistant and waterproof protective cover shell. The data measured by the pressure sensor and the temperature sensor are acquired by the acquisition board and sent to the computing and processing board for computing and processing. The computing and processing board displays the calculation results in real time on the display operation panel and sends them to the storage and output module. The storage and output module is provided with an Ethernet interface. The computing and processing board uses the following steps to perform calculations: S1, calculate the total volume V of the high-pressure air system based on the volume of each gas cylinder in the system, in m 3 ; S2, before high pressure blowing, calculate the temperature T of the high pressure air in the cylinder according to the measured values ​​of the pressure sensor and the temperature sensor. 0 , unit is K, the pressure of high pressure air in the cylinder is P 0 , in MPa, look up the high-pressure air density table and calculate the high-pressure air density R in the cylinder by interpolation. 0 , unit is kg / m 3 ; S3, after the high-pressure blowing starts, the cylinder pressure P during the blowing process is calculated through the measured value of the pressure sensor 1 , in MPa, the gas temperature T at the corresponding moment is calculated by the formula 1 , unit is K, T 1 =T 0 *(P 1 / P 0 ) 2 / 7 ; S4, through air temperature T 1 and the static air pressure P 1 , check the high pressure air density table and calculate the air density R by interpolation 1 ; S5, calculate the rate of change of high pressure air density over time by interpolation method, dR 1 =(R 1 -R 1 ’) / dt; S6, based on the total volume V of the high-pressure air system, the rate of change of the high-pressure air density over time dR 1 , calculate the mass flow rate Q of air, Q = V × dR 1 .

2. The high pressure blow-off mass flow meter based on gas cylinder pressure according to claim 1, Features: The display operation panel, sampling board, calculation processing board, storage and output module are integrated into a secondary instrument box.

3. The high pressure blow-off mass flow meter based on gas cylinder pressure according to claim 1, Features: The pressure sensor has a response time of less than 0.1 ms and a measurement range of 0.1 MPa to 20 MPa.

4. The high pressure blow-off mass flow meter based on gas cylinder pressure according to claim 1, Features: The temperature sensor has a response time greater than 1 second, a measurement range of -50°C to 100°C, a resolution of 0.1°C, and a probe rod length that is 30 to 50 mm longer than the height of the high-pressure air bottle head.

5. The high pressure blow-off mass flow meter based on gas cylinder pressure according to claim 1, Features: The acquisition frequency of the sampling board is not less than 5000 Hz.

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