Maintenance
Waukesha Cherry-Burrell
Page 46
95-03057
11/2012
Scraper Blade Removal & Replacement
1.
Remove scraper blades by lifting up and pulling them from
the pins. PEEK Blades have a locking groove.
2.
After lifting, push to the right before pulling them from the
pins.
NOTE:
Blades should be kept in the same position on mutator
shaft throughout life of blade. Make sure blades are removed and
reinstalled in the same location on the shaft.
Reverse this procedure for installation. Make sure beveled edge
is installed toward shaft.
Scraper Blade Wear
Worn blades reduce heat transfer efficiency and can cause
excessive wear on the product tube wall.
As the scraper blades scrape across the interior of the heat
exchanger tube, they wear into the contour of the tube. A flat
surface called the heel and a burr or feathered edge develops at
the contact area on the side of the blade that is against the tube
wall. See Figure 25.
The blades must be maintained to achieve maximum
performance. When the heel of the blade reaches a maximum of
1/16" (1.6 mm) on metal blades or 1/8" (3.2 mm) on plastic
blades, they must be replaced or re-sharpened.
Blade Sharpening
Scraper blades can be sharpened by several methods,
depending on the blade material.
The best method utilizes a high speed 45° cutter and fixture that
keeps the backside of the blade perpendicular to the cutting
edge. The cutting edge of the blade should be parallel to the back
surface of the blade within 1/64".
A new universal blade is 2 inches wide by 6 inches long.
For mutator shafts that are 4-1/2 inches in diameter or larger, the
blade should not be sharpened to a blade width of less than 1-3/8
inches.
For mutator shafts that are 4 inches in diameter, the blade should
not be sharpened to a blade width of less than 1-1/2 inches.
Stainless steel blades for the 5-1/4 inch mutator shafts are 1-9/16
x 23-29/32. The minimum width after sharpening is 1-3/8 inches
and the sharpening edge is at a 15-degree angle.
Figure 24 - Scraper Blade Removal
Figure 25 - Blade Wear and
Sharpening
