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Emco Controls A/S
Høgevej 6
DK- 3400 Hillerød
Denmark

Phone +45 4576 94 00
Fax +45 4576 94 01

emco@emco.dk

Emco Controls A/S receives the Gazelle award from the leading Danish business newspaper Borsen in recognition of being one of Denmark's fastest growing companies.

 

    

 

Venturi Tube Type RH for High Pressure Gas Flow

 
Principle
EMCO venturi tubes are used as primary elements in flow measurement of high pressure gas and steam according to the differential pressure principle. In high pressure gas flow, the discharge coefficient increases for venturi tubes according to ISO 5167-4, whereas the venturi type RH, having a total inlet convergent angle of 10,5°, provides a discharge coefficient more in accordance to a physical model.
 
venturi tube type RH for high pressure gas flow

Construction
 
Design Standards :
ISO/TR 15377, ISO 5167-4, ASME MFC-3M
 
Sizes :
DN 50 — 200, 2” — 8” according to ISO/TR 15377.
 
Beta (d/D) :
0,4 £ £ 0,75
 
Pressure rating :
PN 40 - 640, 300 - 2500 lbs, ISO PN 50-420.
 
Material :
Carbon steel, AISI 316, Duplex, 254 SMO others on request.
 
Mounting style :
Weld ends according to EN 9692-1 or ANSI B16.25. Flanges acc. to DIN or ANSI B16.5 standards or Grayloc Clamp connections.
 
Pressure taps :
Weld ends Ø 21.3 mm, 26.9 mm, thread connection 3/8", 1/2" BSP, 1/2" NPT, or flanged.
 
Tapping hole size : 4 mm
Tappings :
Single pressure tappings or 2x4 tappings each arranged with an external annular ring to equalise the pressure.
 
Inlet cone :
10,5°
 
Outlet cone :
7 — 15 °
 
Technical Data
Accuracy :
1 % (according to ISO/TR 15377) uncalibrated, ¼ % calibrated
 
Pressure loss :
 
Depending on outlet cone between 10 - 15 %
 
Limits for Re. No. :
 
 
3 x 10 5 < ReD, 24000 < Re*
(Re* = (throat tapping inner d/venturi throat d) x Red.)
 
Accessories : Shut off valves and condensing chambers for steam flow.
The required straight pipe run in front of the venturi tube depends on the disturbance and beta (d/D).
 
Diameter ratio
b
Single 90° bend
Two or more 90° bends in the same plane or different planes
1
2
3
A B A B
0,30
3
a
3
0
0,40
3
a
3
0
0,50
3
a
3
0
0,60
6
3
6
3
0,70
17
3
22
3
0,75
24
6
27
6
Column A: without additional uncertainty
Column B: with 0,5 % additional uncertainty.
a: Data not available.
 
ISO/TR 15377 Table 7

Download
EMCO venturi tube type RH brochure (pdf)
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