Space Science Services, Inc.

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Other Services:

 

   Fabrication and Erection Quality Assurance Inspectors
   Nondestructive Testing Training Programs
   Quality Assurance Programs
   Welding Procedure And Weld Qualification Testing Services
   Metallurgical Analysis
   Chemical Analysis
   Physical Testing

     
 

Batch Digesters:

 
Batch Digesters deteriorate in the course of normal operation. This deterioration can be detected upon NDT inspection.  Examples include: 
general wall thinning by corrosion, corrosion around nozzles, weld washing and under-cutting. Weld discontinuities (e.g. linear indications and porosity) are also  revealed by the inspection. Stainless steel overlaid digesters may experience deterioration of the overlay and corrosion of the carbon steel beneath the overlay.

(click for larger view)

 
Industry recommends that ultrasonic "B" Scan is the preferred inspection method of batch digester shell thickness. Some studies have shown that performing the inspection from the outside (although, it can be performed from either side) provides the most accurate results especially when trying to determine the difference in the carbon steel and stainless steel thickness.
     
 

Dryer Roll Inspections:

 
Shell thinning generally occurs on the inside of the dryer shells due to erosion caused by loose balance weights, siphons, etc. Thinning can be gradual across a wide area or may be present as localized grooves. Undetected casting defects may also enlarge. Thinning of the shell can lead to catastrophic rupture resulting in damage to large sections of the machine. Dryer heads may crack due to fatigue or chemical etching may occur due to harsh cleaning solutions. Dryer bolts may be affected in the same manner. 

The D2S system scans and records velocity and time of flight information, insuring proper calibration at any point on the roll. The D2S also provides the flexibility and reporting capabilities of the Analyst software.

 
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