Product - Two-stage Dump Tube
​​​​​​​​​​The dump tube is used together with a steam conditioning valve in applications such as turbine bypass where steam is dumped into a condenser. The process can, in case of high pressure drops between the steam conditioning valve outlet and the condenser, be a source of high levels of noise. In order to remedy this, IMI CCI has developed a multi-stage dump tube which splits the pressure drop over a series of pressure reducing stages, thus reducing the noise level. IMI CCI has experts in the field of dump tubes, with experience from thousands of plants, that can provide support at the design stage.​

​Key features

  • The dump tube is welded to the steam pipe downstream of the bypass valve
  • The dump tube is a fixed orifice, which reduces the bypass steam pressure down to the pressure of the condenser
  • Our dump tubes are carefully calculated to allow it to be used as a flow meter
  • There are two main applications for the dump tube:
    • Water cooled condenser, where the dump tube is mounted in the condenser
    • ​Air cooled condenser, where the dump tube is mounted in the bypass line connected to a header going from the turbine outlet to the air-cooled condenser


  • The two-stage dump tube allows for reduced noise levels thanks to its multi-stage pressure-reducing design
  • Each dump tube is specifically designed for each application. The steam entering the water-cooled condenser from the bypass valve can be directed to avoid damage to the condenser internals or to the steam turbine internals
  • The expensive large diameter pipe between the bypass valve and the condenser can be reduced and made very short
  • Accurate steam temperature control
  • Optimised size of bypass valve and dump tube gives low investment cost​
  • Dump tubes are sized together with the bypass valve to minimise cost while maximising performance


Installation example

Dumping steam into the condenser is a delicate operation with a large number of elements that must be properly considered during the design stage. The condenser is a very costly component in the system that is sensitive to both pressure and heat. Not only is the design of the individual components (the turbine bypass valve and the dump tube) important, but so is the control system used. IMI CCI provides a complete system with turbine bypass valve, dump tube, spray water control valve and control algorithm for controlling the spray water injected into the steam.
The example shown below is a feed-forward control scheme in a bypass to air-cooled condenser application. Feed-forward control  calculates the required water injection flow based on the following data:
  • Inlet enthalpy
  • Inlet steam flow
  • Spray water enthalpy
  • Required enthalpy of the fluid dumped into the condenser

The algorithm developed by IMI CCI is to be used in customer’s Distributed Control System - DCS. Inlet steam pressure, temperature, and bypass valve outlet pressure give the actual steam flow into the valve. The required spray water flow to reach the desired outlet temperature is calculated and compared with the actual spray water flow, measured via a flow-meter. The result is a control signal to the positioner on the spray water valve. A pressure transmitter measures the steam pressure before the dump tube. Since the dump tube is a fixed orifice, the signal indicates the flow through the dump tube.

The dimensions of the dump tube stages and the orientation of the orifice are determined by the following factors:
  • Operating conditions of the steam conditioning valve (pressure, temperature, flow, pipe dimensions and percentage of free water through the dump tube.
  • Operating conditions of the condenser (pressure, temperature).
  • Condenser design.
Alloy steel is always used for our dump tube design, as carbon steel is unsuitable. Stainless steel is available upon request.

Latest News

Important Update – COVID-19
18 March 2020
Valve Doctor programme celebrates 20th anniversary
16 September 2019
Unconventional support for the unconventional oil and gas industry
01 July 2019
17 June 2019
IMI CCI showcases choke valve at DUG Rockies conference
04 June 2019
Jackie Hu appointed Divisional Managing Director of IMI Critical Engineering
07 March 2019
Roy Twite to succeed Mark Selway as Chief Executive of IMI plc
05 March 2019
IMI Critical holds Safety Summit
21 September 2018
New HSE handbook to help keep field service engineers safe
10 August 2018
Safety first at IMI Critical
31 July 2018
IMI InterAtiva’s Series RK Valves certified ‘fire-safe’
24 July 2018
IMI CCI participates at regional VPP Safety Summit
08 June 2018
Largest Romanian customer recommends IMI Remosa
10 May 2018
Lean success in IMI Critical back office functions
04 May 2018
Isolation valves adapted for Fluidised Catalytic Cracking applications
30 April 2018
IMI Critical Korea closes in on world-class LEAN performance
27 April 2018
IMI board tours IMI Critical businesses
25 April 2018
New positioner software tools from IMI STI
08 February 2018
Launch of Zero Backlash Scotch Yoke Mechanism
16 January 2018
IMI Critical Korea certified to sell actuators in Europe
20 September 2017
IMI Critical named ‘supplier of the year’ by Korea’s Doosan
19 September 2017
100th Valve Doctor graduates from IMI Critical
13 September 2017
Top HSE certification for IMI Critical’s California site
12 September 2017
Launch of High Endurance Actuator
21 April 2017
Launch of AB6350 valve
06 April 2017
Launch of 100DPC Multi-trim
17 March 2017
Launch of 840GS control valve
22 December 2016
IMI Critical to exhibit new technology at ADIPEC 2016
25 October 2016
New graduates join IMI Critical in four countries
22 September 2016
IMI Critical to take stand at ONS 2016 in Norway
16 August 2016
IMI Critical opens new China plant in Qingpu
27 July 2016
IMI CCI Korea celebrates 2,000 days of no “Lost Time Accident”
25 July 2016
Visit to IMI Z&J Germany by the Russian Economic Bureau from Bonn
11 July 2016
IMI Z&J Düren moves into modern offices
08 July 2016
IMI Critical Engineering forms strategic partnership with MRC Solberg & Andersen
05 April 2016
IMI Way Day 2016 date announced
01 March 2016
NEW IMI Eye – fourth edition
26 February 2016
IMI Critical co-locates China businesses
20 January 2016
IMI CCI Switzerland gains certification for new generation safety valves
18 December 2015
IMI Critical rise to Dragon challenge
30 November 2015
IMI STI achieves CRCC approval for new products
24 November 2015
IMI Truflo Marine Attend the Engineering Technology and Innovation Exhibition 2015
23 November 2015
IMI CCI Sweden secures new contracts on three continents
23 November 2015
IMI Critical Engineering appoints new petrochemicals head
05 November 2015
IMI CCI Czech Republic gains ‘Safe Enterprise’ certification
03 November 2015
IMI Critical announces 90mRMB investment in China
29 October 2015
IMI CCI SriCity wins regional safety award
27 October 2015
Key clients attend grand opening of new Aberdeen facility
23 October 2015
IMI companies ‘act as one’ to deliver for customer
02 October 2015
IMI CCI Sri City approved by NTPC
01 October 2015
IMI Critical Engineering showcases innovation at Valve World Expo Asia
28 September 2015
Nexen awards IMI Orton
25 September 2015
IMI Critical Engineering celebrates opening of new Jubail repair centre
23 September 2015
IMI Critical and IMI Precision join forces at Valve World Expo + Conference Asia 2015
21 September 2015
IMI Critical Engineering opening of new Jubail Repair Centre
18 September 2015
IMI CCI India manufactures first 1050MW turbine bypass valve
20 May 2015
Largest ever contract for IMI Critical Engineering
18 February 2015
New Houston facility opens
12 February 2015
IMI Critical completes acquisition of Bopp + Reuther
02 January 2015
IMI Critical takes family of brands to Valve World 2014
11 December 2014
IMI STI doubles size of Italian plant
20 October 2014
Product - Two-stage Dump Tube