High-pressure blowing mass flowmeter based on gas cylinder pressureTechnical Field
The invention relates to the field of high-pressure blowing mass flow meters, in particular to a high-pressure blowing mass flow meter based on gas cylinder pressure.
Background
The accurate measurement of the high-pressure blowing mass flow is an industry problem, compared with low-pressure low-speed gas, water medium and the like, the high-pressure air has severe expansion in the flowing process, so that the density of the high-pressure air is not constant, and various flowmeters developed on the premise of constant medium density, such as turbine flowmeters, vortex shedding flowmeters, roots flowmeters, thermosensitive temperature-sensing flowmeters and the like, cannot be used for occasions of high-pressure air mass flow measurement.
The current commercial high-pressure air mass flow meters are all based on the coriolis force principle, such as RHM 30 type air mass flow meters of RHEONIK company in Germany, DMF type mass flow meters of real-time automated equipment limited company in Beijing, and the like, and the measuring principle is that the mass flow rate of high-pressure air is calculated by converting and measuring the Coriolis force generated when the high-pressure air flows through a specific pipeline. The mass flowmeter designed based on the principle is characterized in that two tennis racket-mounted annular pipelines for generating Coriolis force are needed, the size of each annular pipeline is 100-400 times of the diameter of a detected pipeline, and the mass flowmeter of the type generally needs to occupy a large space, so that the whole size and the weight of the mass flowmeter are overlarge, and the mass flowmeter is mainly used in occasions with insensitive space requirements such as laboratories and is not suitable for being used in ship water tanks. The sensor adopts a mechanical method to measure, is sensitive to external vibration and impact, and does not meet the use requirement of the ship environment. In addition, in order to avoid the influence caused by vibration impact in the environment, the sensors need to process measurement data, so that the measured mass flow has 1-2 s of delay in actual use, and the accurate closed-loop control requirement of the high-pressure blowing process with the duration of only a few seconds cannot be met.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, create conditions for the high-pressure air mass flowmeter to be miniaturized, shock-resistant, quick-response and the like, and provide a high-pressure blowing mass flowmeter based on the pressure of a gas cylinder for the application of the high-pressure air mass flowmeter on a ship.
The invention aims at realizing the following technical scheme.
The utility model provides a high pressure blows mass flowmeter based on gas cylinder pressure, includes high-pressure air cylinder head, pressure sensor, temperature sensor, pressure-resistant waterproof safety cover casing, watertight withstand voltage cable joint, display operation panel, sampling integrated circuit board, calculation processing integrated circuit board, storage and output module, gas cylinder outlet connection. The high-pressure air bottle sealing head is arranged at the tail end of the high-pressure air bottle and is connected with the high-pressure air bottle through threads, the pressure sensor is arranged on the high-pressure air bottle sealing head and is used for measuring the internal static pressure of the air bottle, the temperature sensor is arranged on the high-pressure air bottle sealing head, the pressure-resistant waterproof protective cover shell covers the pressure sensor and the temperature sensor and is arranged on the high-pressure air bottle sealing head through threads, the watertight pressure-resistant cable connector is arranged at the tail part of the pressure-resistant waterproof protective cover shell, data measured by the pressure sensor and the temperature sensor are acquired through the acquisition board card and then are sent to the calculation processing board card for calculation processing, the calculation processing board card displays the calculation result on the display operation panel in real time and is sent to the storage and output module, and the storage and output module is provided with an Ethernet interface.
In the technical scheme, the display operation panel, the sampling board card, the calculation processing board card and the storage and output module are integrated into the secondary instrument box.
In the above technical solution, the computing processing board card performs computing by adopting the following steps:
S1, calculating the total volume V of a high-pressure air system according to the volumes of all the gas cylinders of the system, wherein the unit is m3;
S2, before high-pressure blowing, calculating the temperature T0 of high-pressure air in the gas cylinder according to the measured value of the pressure sensor and the measured value of the temperature sensor, wherein the unit is K, the pressure P0 of the high-pressure air in the gas cylinder is MPa, and the high-pressure air density R0 in the gas cylinder is calculated by checking a high-pressure air density meter through an interpolation method, and the unit is kg/m3;
S3, after high-pressure blowing is started, calculating to obtain the pressure P1 of the gas cylinder in the blowing process according to the measured value of the pressure sensor, wherein the unit is MPa, and calculating the gas temperature T1 at the corresponding moment according to a formula according to the unit is K and T1＝T0*(P1/P0)2/7;
S4, checking a high-pressure air density table through an air temperature T1 and an air static pressure P1, and calculating the density R1 of the air through an interpolation method;
s5, calculating the change rate of the high-pressure air density along with time by an interpolation method,
dR1＝(R1-R1’)/dt;
And S6, calculating the mass flow Q of air according to the change rate dR1 of the high-pressure air density along with time according to the total volume V of the high-pressure air system, wherein Q=V multiplied by dR1.
The high-pressure blowing mass flowmeter based on the gas cylinder pressure enables the working principle of the high-pressure air mass flowmeter to change radically, not only can high-flow high-pressure air flow with severe density change be measured, but also the special requirements of a Coriolis force method on a measuring pipeline structure can be avoided, the high-pressure air mass flowmeter is simplified in structure, the volume and the weight are greatly reduced, and the high-pressure blowing mass flowmeter can be used for space-sensitive measuring occasions such as ship water tank high-pressure blowing pipelines, and particularly for application occasions requiring measuring of high-pressure blowing total mass flow.
Drawings
FIG. 1 is a schematic view of an embodiment of the high pressure blow-off mass flowmeter of the present invention based on cylinder pressure.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the detailed description is presented by way of example only and is not intended to limit the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
As shown in fig. 1, the embodiment of the invention provides a high-pressure blowing mass flowmeter based on gas cylinder pressure, which comprises a high-pressure air cylinder 1, a high-pressure air cylinder end socket 2, a pressure sensor 3, a temperature sensor 4, a pressure-resistant waterproof protective cover shell 5,O, a sealing ring 6, a watertight pressure-resistant cable joint 7, a display operation panel 8, a sampling board card 9, a calculation processing board card 10, a storage and output module 11 and a gas cylinder outlet joint 12. The outlet of the high-pressure air bottle 1 faces downwards, so that accumulated water in the air bottle can be avoided. The high-pressure air bottle sealing head 2 is arranged at the tail end of the high-pressure air bottle, is connected with the high-pressure air bottle 1 through threads, and is sealed through a red copper sealing gasket. The pressure sensor 3 is arranged on the high-pressure air cylinder seal head 2 through threads, is sealed through a red copper gasket, measures the static pressure in the air cylinder, has response time less than 0.1ms and has a measuring range of 0.1-20 MPa. The temperature sensor 4 is arranged on the high-pressure air cylinder seal head 2 through threads and is sealed through a red copper gasket. The pressure-resistant waterproof protective cover shell 5 is mounted on the high-pressure air cylinder seal head 2 through threads and is sealed through an O-shaped ring 6. The watertight pressure-resistant cable joint 7 is arranged at the tail part of the pressure-resistant waterproof protective cover shell 5 and is used for providing a watertight cable channel. The display operation panel 8, the sampling board card 9, the calculation processing board card 10 and the storage and output module 11 are integrated into a secondary instrument box. The response time of the temperature sensor 4 is more than 1s, the measurement range is-50 ℃ to 100 ℃, the resolution is 0.1 ℃, and the length of a probe rod is 30-50 mm longer than the height of the high-pressure air cylinder seal head 2. The acquisition frequency of the sampling board card is not lower than 5000Hz. The data measured by the pressure sensor 3 and the temperature sensor 4 are acquired by the acquisition board 9 and then sent to the calculation processing board 10 for calculation processing, the calculation processing board 10 displays the calculation result on the display operation panel 8 in real time and sends the calculation result to the storage and output module 11, and the storage and output module 11 is provided with an Ethernet interface. The gas cylinder outlet joint 12 is positioned at the bottommost part of the high-pressure gas cylinder 1, is connected with the high-pressure gas cylinder 1 through threads, and is sealed through a red copper sealing gasket.
In the above embodiment, the high-pressure air bottle 1, the high-pressure air bottle seal head 2, the pressure-resistant waterproof protective cover shell 5 and the air bottle outlet connector 12 are all made of titanium alloy materials, and are subjected to surface passivation treatment, so that seawater corrosion and seawater pressure can be resisted.
In the above embodiment, the computing processing board 10 performs the following steps:
S1, calculating the total volume V of a high-pressure air system according to the volumes of all the gas cylinders of the system, wherein the unit is m3;
S2, before high-pressure blowing, calculating the temperature T0 of high-pressure air in the gas cylinder according to the measured value of the pressure sensor 3 and the measured value of the temperature sensor 4, wherein the unit is K, the pressure P0 of the high-pressure air in the gas cylinder is MPa, and the high-pressure air density R0 in the gas cylinder is calculated by checking a high-pressure air density meter through an interpolation method, and the unit is kg/m3;
S3, after high-pressure blowing is started, calculating to obtain the pressure P1 of the gas cylinder in the blowing process according to the measured value of the pressure sensor 4, wherein the unit is MPa, and calculating the gas temperature T1 at the corresponding moment according to a formula according to the unit is K and T1＝T0*(P1/P0)2/7;
S4, checking a high-pressure air density table through an air temperature T1 and an air static pressure P1, and calculating the density R1 of the air through an interpolation method;
s5, calculating the change rate of the high-pressure air density along with time by an interpolation method,
dR1＝(R1-R1’)/dt;
And S6, calculating the mass flow Q of air according to the change rate dR1 of the high-pressure air density along with time according to the total volume V of the high-pressure air system, wherein Q=V multiplied by dR1.
What is not described in detail in this specification is prior art known to those skilled in the art.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents and improvements made within the spirit and principles of the invention are intended to be included within the scope of the invention.