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Venturi Desuperheaters Type 6950

Venturi desuperheaters reduce steam temperature by bringing superheated steam into direct contact with water. The steam is cooled through the evaporation of the water. These desuperheaters are recommended for use under a wide range of conditions, including steady and variable flows. They can be installed horizontally or vertically up. When installed vertically up, turndown ratios can be increased substantially.
 
Operation
Water entering the desuperheaters is preheated in the circulatory chamber around the water diffuser tube and is introduced in many small jets to assist final atomization by the steam flow through the left of the throat. When leaving the throat, the mixture of steam and water enters the venturi section for turbulent mixing prior to entering the main steam line in a fog-like condition without contacting the sidewalls providing maximum desuperheating effectiveness and a minimum of wear in the discharge piping. The water pressure required should equal the operating steam pressure.
 
Performance
Venturi desuperheaters are normally used in areas where atomizing steam is not available. Turndown ratio is dependent upon a wide variety of factors, such as installation (horizontal or vertical), amount of residual superheat, and piping. Depending on exact flow conditions, units are capable of 50% to 5% flow variation. Pressure drop varies between 2 psi and 10 psi.
 
Construction, Sizes and Ratings
Type 6950 Desuperheater is mounted in and supported by the pipeline
Sizes from 2" - 6 " in cast carbon or alloy steel in ratings to 900 lb.; 8 " and up cast body with fabricated tail in ratings to 900 lb. (cast bodies and tails stocked in carbon steel 1501b. and 300 lb. up to 6").
A 2 3 4 6 8 10 12 14 16
B 11-7/8 15-9/16 19-7/16 28-13/16 40-3/8 47-13/16 57-15/16 69-1/16 77-13/16
C 1/4 1/4 3/8 3/4 3/4 3/4 1 1-1/4 1-1/2
D 1-7/64 1-3/8 7/8 1-9/16 1-7/16 1-5/8 3-1/2 2-3/4 2-11/16
E 2-1/16 2-11/16 2-3/16 3-1/2 2-15/16 3-11/16 5-7/16 5-11/16 6-1/16
 
Type 6940 Desuperheater is mounted directly in the pipeline (like the 6950)
Sizes from 2" - 16" in cast carbon or alloy steel in ratings to 2500 lb.; 18" and above fabricated carbon or alloy steel in ratings to 1500 lb.
A 2 3 4 5 6 8 10 12 14 16
B 11-1/2 15-5/16 20 24-1/8 30-1/16 41 49-1/2 59-15/16 72 81-3/4
B 11-3/4 16-5/16 20-1/16 25 30 41 50-3/4 59-15/16 72 81-3/4
B 12-1/2 16-13/16 20-1/16 25-13/16 31-7/16 41 49-5/8 62-9/16 73-3/8 81-3/4
C 1/4 1/4 3/8 1/2 3/4 3/4 3/4 1 1-1/4 1-1/2
D 2 2-1/2 2-1/2 3 4 5-1/4 7 8-1/2 9 10-1/2
 
Type 6940M Desuperheater is a miniture version of the 6940
Sizes from 1/2"- 1-1/2" in carbon, alloy or stainless steel barstock construction up to 600 lb. rating with NPT, socket weld or flanged connections.
Size/Conn A 1/2 3/4 1 1-1/2
Length B 4-7/8 6 7-3/8 10-3/16
OAL 150#, 300# & 600# BB 9-1/2 10-1/2 12 15
Water Inlet (NPT) C 1/8 1/8 1/4 1/4
Inlet Fact to Water Inlet CL D 2 2 2-1/4 2-5/8
Body Thickness DD 4-5/16 4-1/4 4-9/16 5-1/32
 
 
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