V cone flowmeter

One, the introduction:
LGV v-cone flowmeter with V series V cone in the flow field generated by the throttling effect, measured by detecting the differential pressure of upstream and downstream of the flow.Compared with ordinary throttling, it changed the throttling layout, from the center hole throttle annular throttle instead.Practice shows that compared with other flowmeters, V cone flowmeter V cone flowmeter has high accuracy, good stability for a long time, the installation condition limits small and wear resistance, wide measuring range, small pressure loss and suitable for the advantages of smudges.And V cone itself as the flow field of the rectifier and become a new type has unique properties of excellent flowmeter.
Second, the measuring principle:
LGV v-cone flowmeter consists of a series of V in the measuring tube coaxial installation pointed cone and the corresponding pressure, the measuring tube is machined, the pointed cone end produce differential pressure, the differential pressure of high pressure (positive pressure) is at the upstream fluid contraction front wall static pressure measurement, and low pressure (negative pressure) is taken from the cone pointing downstream face pressure on the center of a cone hole.
Towards the top of the cone to flow between the cone and its tail is a sharp corner, the edge of the mating surface to make fluid before into the low pressure area downstream of a transition zone of smooth.
Due to fluid near the pipe center axis, not forced to contraction and not a blockage, to change fluid flow direction, but using the new structure of V type cone throttling device realized gradually to the fluid toward the side wall of tube shrinkage, make V cone flowmeter has a series of unique advantages.The low voltage side produce high-frequency low-rising small vortex, the differential pressure and differential pressure transducer is measured is low noise signal, can make the differential pressure transmitter measured high resolution ratio, V cone flowmeter to get wide range ratio and good repeatability.
V cone flow sensor produced by the square root of the differential value is proportional to the flow of relationships:
Qv = (c. epsilon)/(1 - beta 4) 0.5 (PI / 4). D2.0.5
Among them: Qv: fluid volume flow
C: the outflow coefficient;
Epsilon: fluid expansion coefficient;
Beta: throttling ratio;
D: throttle diameter;
Δ Ρ: differential pressure value;
Rho 1: working condition of fluid density.
Third, the application of V cone flowmeter, conditions and maintenance:
Mass media: coal gas, natural gas, including humidity below 5%), all kinds of hydrocarbons (including HC gas moisture), all kinds of rare gas (hydrogen, helium, argon, oxygen, nitrogen, etc.), chlorine, wet chlorine gas, air (including water cut, including SiO2 particles and other air suspension), flue gas, saturated steam (including steam and water two phase flow), superheated steam, water, etc.
Article: from cryogenic to supercritical condition, the maximum temperature of 700 ℃, the maximum pressure of 40 mpa.
Computing: each cone flowmeter based on the nature of the fluid, pressure and temperature with special software to calculate.Users can according to your own application conditions (the components of the measured medium, temperature, pressure, pipe diameter, maximum flow, flow, the minimum flow, to allow maximum pressure loss) choose beta.
D n: cone flowmeter is a maintenance free, do not need regular maintenance and calibration.
Four, V cone flowmeter has the following features:
Flow meter accuracy: + / - 0.5%, plus or minus 1.0%, plus or minus 1.5% accuracy of system must be reference to application conditions and the precision of the second table.
Repeatability: better than that of plus or minus 0.1%
Wide range than: under normal circumstances of 10:1, if necessary can also be increased.
Straight pipe low requirements: flowmeter 0 ~ 3 d straight pipe before and after the 0 ~ 1 d straight pipe can guarantee the accuracy of measurement.Experiments show that V cone flowmeter can close to single or double bend in different plane bend and little impact on accuracy.
Good long term stability: the cone shape design to ensure that when fluid flows through the cone is a gradual process, no mutation, beta can keep unchanged for a long time, instrument can be use for a long time without calibration.
Signal stability: all differential pressure flowmeter can have "fluctuations", that is to say, even if the fluid is very stable, signal produced by a throttle unit will fluctuate.For orifice, the throttling parts after the formation of the vortex is longer, the long spiral will cause a high amplitude, low frequency wave signal, the signal will cause interference to the differential manometer readings.And cone flowmeter can be formed in its downstream small vortex, cause a low-rising, high frequency wave signal.
Small pressure loss, because there is no prominent baffle, so conical three out of four permanent pressure loss is lower than orifice flow meter.
No stranded dead zone: cone "purging type" design there is no dead zone, therefore, not accumulate fluid debris in the cone, viscous slag or impurities.
Mixer role: V cone flowmeter downstream vortex is generated by the short spiral, can be in the downstream mix medium, therefore, the current V cone flowmeter in as well as the work flow, but also on many occasions used as static mixer, can rapidly and fully stir well to media.
Five, the V cone flowmeter the main technical indicators:
1. Nominal menstruation: 50 mm or less DN 1800 mm or less
2. The nominal pressure: PN 40 mpa or less
3. The range of Reynolds number: 8 x 103 Red or less 107 or less
4. The level of accuracy: 0.5, 1.0
5. Repetitive: 0.1% or less
Straight pipe before 6. : 1 ~ 3 d, straight pipe: after 3 ~ 5 d
7. Small pressure loss, is only 1/2 ~ 1/3 of orifice plate
Result 8. The cone trailing vortex small, stable output pressure side, small fluctuation stability is good.
9. Range than: wide flow range can reach: 1:15
The flange type:
1, connection mode: flange (flat welding and butt welding);
2, size: DN15 ~ DN2000;
3, apply pressure method: socket welding, flange, screw thread;
4, pressure: 0 ~ 40 mpa;
5, temperature: - 40 ~ 850 ℃;
6, material: 304 stainless steel, 316 l stainless steel and 20 # carbon steel selection (see table).
7, application: liquid, gas, steam;
8, suitable medium: widely used in municipal, electricity, chemical industry, petroleum chemical industry, metallurgy, food processing and other industries in the flow measurement, suitable for almost all the gas and liquid medium.
Direct welding type:
1, the mode of connection: pipe welded directly to the process;
2, size: DN15 ~ DN2000;
3, apply pressure method: socket welding, flange, screw thread;
4, pressure: 0 ~ 40 mpa;
5, temperature: - 40 ~ 850 ℃;
6, material: 304 stainless steel, 316 l stainless steel and 20 # carbon steel;
Six cone of sensor and differential pressure transmitter, V V cone flowmeter:
In accordance with user requirements, with V cone sensors and differential pressure transmitter the supply of flow measuring instrument is divided into two categories:
1, V cone sensors provide only the differential signal detection part of the cone and measuring pipe (V), does not provide differential pressure transmitter, part three valve group and flow display, output signal for the differential pressure.By the users themselves.
2, v-cone flowmeter by V V cone of sensor and differential pressure transmitter.Have installed points in shape and a size two structures.
Points are installed by an independent V cone of sensor and differential pressure transmitter.V taper between sensor and differential pressure transmitter of pressure pipe connection completed by users themselves.The differential pressure transmitter can form a complete set of supplies.
3, installation is a size product factory has the differential pressure transmitter, three valve group and V cone sensors connected into an organic whole, after users buy a size V cone flowmeter, don't need to join again when using pressure tube.For matching the corresponding flow integrator, pressure transmitter and temperature transmitter can form a complete set of supplies.
Seven, V cone flowmeter installation site:
Even in comparison also can work normally under harsh conditions, but for the sake of the use of safe and stable for a long time, during the installation, please pay attention to the points:
1, the installation place shock and vibration
The factory design of the V cone flowmeter is can withstand the shock and vibration.But should also try to install where no vibration or vibration.
2, installation site ambient temperature conditions
Please try to avoid the flow meter installed in the environment temperature change is big, if the installation location is directly thermal radiation or waste their exposure to day rain, waterproof, heat radiation and ventilation measures should be taken.
3, installation site ambient air conditions
V cone flowmeter should avoid as far as possible in the corrosive environment, if used in the corrosion environment, should have good ventilation and avoid corrosive gas or liquid into the instrument.
Eight, installation requirements:
Guide to transducer pressure of pipe used for the transmission process, if the pressure tube of the gas in the liquid or the gas pipe in the residue, cannot correct for pressure transmission, can produce error, therefore, equipped with guide of pressure pipe should be pay attention to:
Guide the installation of pressure pipe guide valve Angle:
Process fluid is a gas and steam, and guide valve installation position should be above the process piping, process fluid is a liquid lead valve installation position should be at the bottom of the process piping.
1, the process fluid is a gas, transmitter position should be higher than the pressure valve, liquid and steam process of a fluid, transmitter position should be lower than pressure valve.
2, high and low voltage side of the guide tube does not produce temperature difference.
3, application in measuring the steam condenser.
Nine, use notice:
And the postal inspection specifications confirmation:
Play is put on the market after a full inspection, when the user types and specifications, please after receipt of the goods in a timely manner to confirm, and check whether there is damage appearance, types and specifications of engraving on the nameplate on the outside of the flowmeter, and shall confirm the receipt of the goods and packing box parts listed on the packing list whether is complete.
Ten, transportation and storage conditions:
On his way to prevent the transport and handling damage instrument, in the work site prior to installation, please keep this product appearance because the packing condition.
When stored in a need for a long time, please pay attention to the points:
1, in no impact and vibration.
2, avoid exposure to the wind, rain, store environment best in normal temperature is often wet around (25 ℃, 65% RH)
3, try to keep in this product factory packing condition for storage.
4, used a product to save, please make sure the residue within the instrument clean.
Eleven, v-cone flowmeter selection table V:

12 order, design notes:
When you place an order, please provide the following conditions in order to help correct selection of coefficient of v-cone flowmeter specifications and V.
1, pipe size: diameter x wall thickness (mm);
2, measuring medium name: medium density (kg/m3);
3, set the maximum flow: meter on the range of limit (kg/h or m3 / h);
4, process of minimum flow: (kg/h or m3 / h);
5, work pressure (Mpa);
6, work temperature: (° C);
7, such as with our company, please provide together: intelligent flow totalizer.especially pressure range, or pressure transmitter type, range;Temperature range, or models, range temperature transmitter.