Differential type V-cone flowmeter

Differential type V-cone flowmeter
Cone differential pressure flow meter
Operating manual
WIDE PLUS PRECISION INSTRUMENTS CO., LTD.
INDEX
Introduction…………………………………………………………………………2
Principle ……………………………………………………………………………2
Application …………………………………………………………………………3
The characteristics of flow meter …………………………………………………3
Specification…………………………………………………………………………3
Technical features……………………………………………………………………4
Structural form………………………………………………………………………5
Precise pipeline dimension …………………………………………………………5
Model and specification ……………………………………………………………6
Attention of installation and service ………………………………………………7
1
Precise flow measurement
An expert in the field of flow measurement
Two-wire system connection
The following products may be replaced to use: ◆ Orifice plate
◆Venture
◆Nozzle ◆ vortex flow meter
◆ Vortex precession flowmeter
◆Rotameter flow meter
1. Introduction
Cone differential pressure flow meter that is an innovative flowmeter with high-precise flow
measure and specially design to various kinds of difficult occasion carry out high-precisely survey
to fluid.
The product is throttled down a V type cone that is hanged on the center of manifold. This will force
the fluid is centered as the centerline of manifold, and washed around the cone. Compare with
traditional throttling component, this kind of geometric figure has many advantages. This product
doesn’t bring visible influence to its accuracy of measurement because of its special design, and
enable it to apply to difficult measuring occasion such as no straight length, flow disorder, and
biphase compound bodies and so on.
2. Principle
Cone differential pressure flow meter belongs to differential pressure flowmeter that adopted the
principle of conservatio n of energy. As shown in figure 1, when a medium is near measurement
body, its pressure is P1, but when the medium pass over throttling zone of measurement body, its
flow velocity is increased and its pressure is reduced to P2. Connecting P1 and P2 onto
corresponding differential pressure transmitter via take pressure tap, and then work out the change
of the flow according to changes of difference pressure. The fluid is proportional to square root of
flow velocity of the medium in the pipeline. As shown in figure 1.
P2
Take pressure tap w/ low pressure
Direction of fluid
Figure 1
A V type cone is hanged in the center of pipeline. After the fluid washed the cone, its speed
quickened and kinetic energy increased. Kinetic energy improved in the section is switched by a fall
of rest energy below the cone that is, a low pressure zone will be formed by down stream of V type
cone. The quantity of the fluid is in linear with square root of difference pressure produced around
V type. That is Bernoulli theorem of mutual energy transformation in the sealed pipeline.
Q=KY
Where: Q= flow, K= constant, dimensionless, result from different flow
Y=expansion coefficient of gas, dimensionless, Y=1 when non-compression application △ P=P1-P2, p= density of fluid
For cone-type differential pressure flowmeter:
K=
Where: K= instrument ’
s coefficient, dimensionless, g= acceleration of gravity
2
D=internal diameter of pipeline, d=external diameter of the cone, β =ratio of diameter,
dimensionless, C=flow coefficient
3. Application
Application medium
Gas medium scale
Coal gas (coke oven gas, blast furnace gas, generating furnace gas, gas of city pipe), natural gas
(include natural gas covering wet 5% below), air, Oxygen, Nitrogen, Hydrogen, CO2 , CL2 , Methane
gas, Propylene gas, fune, saturated steam, superheating steam, and wet gas and so on.
Liquid scale: water, oil (containing crude oil, gasoline, diesel oil, kerosene, residuum etc.) emulsion,
pure water, hydrogen peroxide, glycerine, alchhol, sewage, benzene and the other various kinds of
liquid.
Application area
● Oil, gas products and transportation
● petroleum refining
● purified water and waste water
● Chemical industry/medical technology
● energy/combined heat and power generation
● mining
● Paper pulp/papermaking
● manufacture
● food and beverage
Application condition
Form deep cooling to ultra critical situation
Temperature: -100℃~500℃
Max. pressure: 40 MPa
Reynolds number scope:8*103~5*106 (wide range)
Full differential pressure scope: form 0.1~dozens of Kpa
4. Characteristics of flowmeter
●
●
●
●
●
●
●
●
●
High accuracy: FS: ±0.5%
High repeatability: ±0.2% or more
Reforming function about the field of flow velocity
Requirement around straight length is lowest
Ratio of wide-range: generally 1∶10 (require even higher)
Low loss of pressure
Difficult application occasion: dirty liquid, wet gas, pulp
Low ratio of noise
Self-cleaning function
5. Specification
Accuracy: ±0.5% F.S. (application of fixed fluid and Reynolds which may be required to specially
check)
Repeatability: ±0.2% or more
Ratio of range: 1∶3 to 10 or higher
Standard β value: 0.45~0.85, special βvalue may be used
Loss of pressure: changes according to ß value and differential pressure
3
Requirement of mounting pipeline: 0~3 times diameter before measuring body
0~1 times diameter after measuring body
Material: carbon-steel, 304 or 316 L stainless steel, P/PTFE or using special material meet users
requirements
6. Technical features
Ratio of wide -range
Because of the design of cone differential pressure flowmeter is unique, its range is bigger,
generally with from 1∶3 to 1∶30. If demand, it may be increased.. When Reynolds number is
above 8000, its output signal is linear; if Reynolds number is below 8000, it needs to being
modified to its output signal.
Requirement of straight length is low
Due to the curve of the fluid is distributed uniformly, compare with other flowmeter, the
requirements for upstream/downstream length is lower. Generally speaking, length both upstream
0~3D and downstream 0~1D will completely meet its requirement. When the product is applied
to large pipeline or limited occasion of installation position, it has irreplaceable characteristics. As
shown in figure 2.
Fig 2
Long-term stability well
Special design in the cone which guaranteed the fluid is a gradation process and has no mutation
when it flow the cone. First of all, the flow went through the cone, and then reached the edge of the
cone again. So the cone couldn’t be damaged frequently, β value will always remain the same. If
the apparatus will be used for a long time but needn’t to be calibrated afresh.
When cone differential pressure flowmeter is to being calculated, its calculation formula adopted is
the same with other differential pressure flowmeter, but the structure of throttling part is the
different with other flowmeter that is realized by the cone in the center of manifolds hanged. This
cone will force the medium in the center of pipeline is washed around the cone, as shown in figure 3,
its distribution of flow velocity is very equal.
Figure 3
Due to the cone is hanged on the center of manifold, it directly contact with freeway zone in the
fluid, to force the fluid at freeway zone is confused with the fluid near low speed zone of tube wall
and then make flow velocity uniformity, therefore, flow velocity at freeway zone continued to
decline. This is why cone differential pressure flowmeter is able to survey lower flow velocity.
Cone differential pressure flowmeter distributes the fluid uniformly under the worst circumstances,
such as upstream the proximate instrument on which has single bend and double bend. The
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distribution of the fluid is more uniform via rectified the cone so as to be sure to get higher accuracy
of measurement under the worst circumstances. As shown in figure 3.
Signal stability well
All of flow meters that adopt difference pressure measure will have signal wave, this is because the
fluid is very stable even if entering measuring instrument. After thought once measuring component,
it will also bring signal wave, and then creating interference to reading of measuring instrument, as
shown in figure 4, that is in contrast to signal wave produced by cone differential pressure
flowmeter and orifice flowmeter.
Figure 4
With “self-cleaning function”
The design of cone-type differential pressure flowmeter is unique, and made its cone doesn’t exist
dead zone, on the cone there don’t accumulate fragments, viscosity or pollutant of the fluid, so with
ability to “self-cleaning”
7. Structural form
Cone differential pressure flowmeter that is divided into three things: precise pipeline type: size
DN15~DN900 or bigger, mutual clip type: sizeDN15~DN150, square type: size DN150~DN900.
this instruction takes pipeline type for example.
8. Precise pipe dimension
Precise pipe dimension
Caliber
Size
Size A
A
Size B
B
Pipeline size
C (CS + Stainless)
Size D
D
Size E
E
Weight
Kg
Caliber
DN15
DN20
DN25
DN40
DN50
DN65
DN80
DN100
DN150
DN200
DN250
DN300
mm
200
200
200
250
300
300
350
400
550
650
700
750
mm
90
90
90
80
85
85
90
90
100
120
120
130
mm
15.8
20.9
26.64
41.78
53.44
63.60
78.84
103.8
154.1
202.7
254.5
303.4
mm
21.3
26.7
33.4
48.3
60.3
73.0
88.9
114
168
219
273
323
G/NPT
1/4
1/4
1/4
1/4
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
4
5
6
7
9
11
16
23
50
118
153
186
5
DN350
750
130
333.5
DN400
750
140
381.0
DN500
900
180
489.0
DN600
1200
200
590.6
DN700
1500
200
743
DN800
1500
240
DN900
1500
240
In the table, if there is any change, don’t another notice.
355
406
508
609
762
813
914
1/2
1/2
1
1
1
1
1
206
262
332
481
562
726
898
8. Model and specification
Model and specification options for cone-type differential pressure flowmeter
Model
WP
Structural
form
Caliber
Flange
Degree of
pressure
Material of
measuring
tube
Material of
measuring
cone
□
□
□ □
□□
□ □□
Description
□ □ □ □ □ □ □ □
NT
Precision pipeline type
PT
GT
Precision square tube type
Ordinary clamp-hold type
DN15 mm~DN300 mm
()
ST
Special size
A
D
ANSI flanged standard
DIN2501 flanged standard
G
S
10
GB9115 national standard
User ’s requirement
1 MPa
16
25
1.6 MPa
2.5 MPa
40
3
4 MPa
304 stainless steel
L
C
316L stainless steel
Carbon-steel
P
T
PTFE/PP
Special material
3
L
304 stainless steel
316L stainless steel
P
3
PTFE/PP
304 stainless steel
L
C
P
316 L stainless steel
Carbon-steel
PTFE/PP
Flange
material
Transmitter
0
1
None
Standard
2
Multi-parameter inspection
with temperature, pressure,
flow etc.
3
Secondary
0
6
User ’s requirement
None
apparatus
1
Standard display
2
3
With display, accumulation
Display, accumulation and
temperature compensation
2
5
Accuracy
0.2 degree
0.5 degree
N
E
Protection
Accessories
0
No protection
Protection
None
1
2
With manifolds
With matching flange
1. Option for example: WP-NT0020G16L310N1
NT: precision pipeline type
0020: caliber DN20
G: GB9115 flange standard
16:1.6 MPa
L: material of measuring tube is 316L stainless steel
L: material of measuring component is 316 L stainless steel
3: connecting flange material is 304 stainless steel
1: standard transmitter
0: without secondary apparatus
N: no anti-explosion
1: with manifolds
2.Please offer the following parameters when ordering
(1) Caliber
(2) Measuring medium
(3) Maximum measuring range (or maximum flow M3 /H)
(4) Normal working scope
(5) Minimum measuring range (or minimum flow M3 /H)
(6) Working pressure
(7) Working temperature
(8) Density of medium
(9) Viscosity of medium
(10) Using local average atmosphere
9. Attention for installation and service
● Fluid direction of coned throttling device should be in conformity to arrow direction of
equipment body
● When measured medium is vapor or higher than 60 degree, which should be additionally
mounting condenser to reduce temperature so as to avoid damaging inspection elements in the
rear of differential pressure
● Before mounting the equipment, please sweeping the pipeline in advance
● Confirming the degree of pressure when ordered, be sure to usage in the range of pressure
● Don’t hit the cone in the pipeline, if there some cones tends to twist, then measuring accuracy
will be affected.
● After select to use the throttling device, random accompanied by a calculation book of range,
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please check up on corresponding condition of process. If there is not the same, then contact us
and afresh calculating range
● Except damage by human factor, this equipment will be carried out quality assurance since the
date of delivery within 18 months
● This equipment matches to use with differential pressure transmitter, its range refers to
calculation sheet, and output signal must act as square root to deal with flow.
● Attached reference diagram of installation
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