DAY & ZIMMERMANN

Condenser and Heat Exchanger Retubing


Pre-Outage Planning:

  • Technical Approach and Schedule Development 
  • Uplift, Vibration, and Beam Strip Analyses
  • Material Selection and Procurement of New Condenser Tubes
  • Tube Pullout Testing

Project Execution:

  • Interference Removal/Reinstallation
  • Waterbox or Waterbox Cover Removal/Reinstallation 
  • Tube Removal/Installation 
  • Tubesheet Repair or Replacement
  • Tubesheet Serrating 
  • Tube Vibration Resolution (Cradle-Lock® Anti-Vibration Tube Stakes)
  • Tube Expansion
  • Tube Inserts/Sleeves
  • Hydrostatic Testing

Retubing Projects:

  • Coating of Tubesheets and/or Waterboxes
  • Disposal of Scrap Tube Material
  • Design and Installation of Cathodic Protection Systems
  • Tube-to-Tubesheet Welding

Condenser and Heat Exchanger Tube Cleaning

Day & Zimmermann deploys plastic or metal scrapers, stainless steel and nylon brushes, plastic pigs, abrasive balls,   low and high pressure water systems, air and water systems, and rotary type systems as appropriate to clean heat exchanger tubes. Day & Zimmermann is capable of cleaning two or more units simultaneously.
 

By removing most types of deposits — from bio-fouling to calcite-type scaling — Day & Zimmermann tube cleaning  services help restore condensers and heat exchangers to their designed cleanliness factor and efficiency, improving performance and tube life while reducing operating costs and tube failures.
 

Cleaning Services:

  • Steam Surface Condensers
  • Auxiliary Condensers
  • Heat Exchangers
  • Coolers

Uplift, Vibration, and Leak Analyses


Uplift Analysis

Using current Heat Exchanger Institute (H.E.I.) Standards for Steam Surface Condensers, Day & Zimmermann's tube uplift analysis compares existing tube material (i.e., "designed for") to new materials incorporating lighter weight and/or thinner wall tubes. 


Vibration Analysis

Day & Zimmermann's Vibration Analysis determines whether or not the existing support plate spacing exceeds the maximum allowable spacing as specified by HEI standards. Vibration analysis considers steam flow, tube size, pitch, tube material, circulating water flow, neck area, and existing support plate spacing. 


The vibration analysis specifies the maximum allowable unsupported tube spacing for the design operating conditions and the condenser pressure at which the maximum allowance unsupported spacing occurs.

 

Day & Zimmermann also offers mass spectrometry leak detection for heat exchanger tubes.


S-Flex Rubber Expansion Joints


Day & Zimmermann’s patented S-Flex rubber expansion joint overcomes the most significant issues inherent in the conventional, rigid, “dog bone” design. 


The unique preformed “S” shaped web allows for a full range of adjustability during installation, effectively eliminating the common issue of misalignment. The flexibility of Day & Zimmermann's S-Flex reduces the loads imparted to the turbine and clamping components by as much as 85% to 90% while decreasing the potential for air in-leakage.


The S-Flex design uses only three layers of fabric — each side skim-coated with rubber during the manufacturing process. This skim-coating process greatly increases the amount of rubber between plies, leading to better adhesion and an increased rubber-to-fabric ratio.


Day & Zimmermann's S-Flex rubber expansion joints are offered in two sizes, accommodating nearly every standard application. It is designed to be compatible with the existing “dog bone” hardware and components:


  • 9-1/2″ Model – this model can be compressed to a height of 9″ and expanded to a height of 10-1/4″ during installation.
  • 10″ Model – this model can be compressed to a height of 9-1/2″ and expanded to a height of 10-3/4″ during installation.

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CONTACT D&Z

1500 SPRING GARDEN STREET, PHILADELPHIA, PA 19130