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| WORKING PRINCIPLE |
| 一、BASIC PRINCIPLE: |
When the fluid is flowing through the throttling element within the pipeline,the flux will be narrowed partially in throttling throat to increase the flow rate and reduce the static pressure,therefore,the deviation of static pressure (or called differential pressure) between the front part and the rear part of the throttling element shall be formed. The more flow rate,the larger diff. Pres., by measuring the diff. Pres., you can evaluate flow passing through device.
The measurement method is based on law of conservation of matter and energy. The diff. Pres. not only relates to flow, but also other factors. Such as, if throttling device type or fluid physical properties is different, the diff. Pres. is different in the same flow.
二、FLOW EQUATION：
|
Qm |
─ |
Mass rate of flow Kg/s |
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|
Qv |
─ |
olume rate of flow at working conditions |
m3/s |
|
C |
─ |
Coefficient of discharge |
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|
β |
─ |
Diamter ratio β=d/D |
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ε |
─ |
Expansibility factor |
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|
△P |
─ |
Differential pressure |
Pa |
|
d |
─ |
Diamter of orifice (or throat) of primary device at working conditions |
(m) |
|
D |
─ |
Upstream internal pipe diameter at working conditions |
m |
|
ρ |
─ |
Density of the fluid |
Kg/m3 |
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| model instruction |
1、Throttling element name |
| Code |
Name |
Code |
Name |
Code |
Name |
| Ａ |
Restriction orifice |
Ｊ |
airfoil type volume measuring device |
Ｒ |
Fastigiate entry orifice plate |
| Ｂ |
standard orifice |
Ｋ |
Wide edge orifice plate |
Ｓ |
double-tier venturi tube |
| Ｃ |
long radius nozzle |
Ｌ |
Venturi Nozzle |
Ｔ |
mechanical processed venturi tube |
| Ｄ |
orifice(nozzle) without upstream or downstream pipe |
Ｍ |
Small orifice plate |
Ｗ |
rough welding iron plate venturi tube |
| Ｅ |
1/4 circle orifice plate(Nozzle) |
Ｎ |
Inner small orifice plate |
Ｘ |
rough molten venturi tube |
| Ｆ |
low pressure loss flowmeter |
Ｏ |
excenric orifice plate |
Ｙ |
double-tier orifice plate |
| Ｇ |
high pressure orifice plate with lens washer |
Ｐ |
ISA1932 Nozzle |
Ｚ |
ANB flowmeter |
| Ｈ |
Ring orifice plate |
Ｑ |
segmental orifice plate |
|
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| 2、Tapping form： |
| Code |
Ｈ |
Ｚ |
Ｆ |
Ｊ |
Ｔ |
| Name |
corner (ring chamber) tappings |
corner (single drill) tappings |
flange tappings |
D-D/2 tappings |
Special tappings |
| ★No the indication method for Restriction orifice. |
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| 3、Internal nominal diameter： |
| Code |
006 |
008 |
01 |
015 |
02 |
025 |
03 |
04 |
05 |
06 |
08 |
10 |
12 |
15 |
| Pipe Diam |
6 |
8 |
10 |
15 |
20 |
25 |
32 |
40 |
50 |
65 |
80 |
100 |
125 |
150 |
| Code |
17 |
20 |
22 |
25 |
30 |
35 |
40 |
45 |
50 |
60 |
70 |
80 |
90 |
100 |
| Code |
175 |
200 |
225 |
250 |
300 |
350 |
400 |
450 |
500 |
600 |
700 |
800 |
900 |
1000 |
★If the pipe diameter is larger than 1000mm,the pipe Diam. Shall be indicated as 1/10 of the actual pipe diameter.
★If the pipe is rectangutar,shall be indicated as1/10 of then length*width of the pipe ,for example ,the size of 1200*1000*3 shall be indicated as 120*100 |
| model instruction |
| 4、Nominal pressure: |
| Code |
0.25 |
00 |
01 |
016 |
02 |
03 |
04 |
05 |
06 |
10 |
16 |
20 |
25 |
32 |
42 |
| Nominal pressure |
0.25 |
0.6 |
1.0 |
1.6 |
2.0 |
2.5
(150#) |
4.0 |
5.0
(300#) |
6.4
(400#) |
10
(600#) |
16
(900# |
20 |
25
(1500#) |
32 |
42
(2500#) |
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| 5、Supply form： |
| Code |
Supply form |
| A |
The complete set with the front 10D and the back 5D measuring pipe (including the connecting and process flange) |
| A1 |
The complete set with the front 10D and the back 5D measuring pipe (including the connecting process flange) |
| A2 |
The complete set with the front 10D and the back 5D measuring pipe (the bevel of pipe end) |
| B |
The complete set with the up-and-down measuring pipe according to HG/T21581-95 (including the connecting and process flange) |
| B1 |
The complete set with the up-and-down measuring pipe according to HG/T21581-95 (including the connecting flange) |
| B2 |
The complete set with the up-and-down measuring pipe according to HG/T21581-95(the bevel of pipe end) |
| B3 |
The complete set without the up-and-down measuring pipe according to HG/T21581-95 |
| C |
The complete set with the up-and-down measuring pipe(upstream 2D & downstream 2D) according to GD87-1101 |
| D |
the flange, the ring chamber, the pressure flange, the throttling element, the pressure tube, the fastener |
| E |
single throttling element |
| T |
special supply form, please give clear indication in the contract or the relevant technical documents. |
| F1 |
flange connection type with duct (pipe)(Including the connecting and process flange) |
| F2 |
Flange connection type with duct(pipe)(Including the connecting) |
| W |
welding type with duct (pipe) |
★The form F1,F2 and W are meant for long radius nozzle, classic venturi tube, double-tier venturi tube, airfoil type volume measuring device,ANB flowmeter,low pressure loss flowmeter |
| 6、Accessorie： |
| Code |
V |
L |
P1 |
P2 |
G1 |
G2 |
J |
C |
| Name |
Valve |
Condenser
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Single Layer Balancer
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Double Layer Balancer |
A Type Seal Pod
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B Type Seal Pob
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Gas Chamber
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Sediment |
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| ★As a rule,valve is globe valve. If special, please remark |
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