Rebuilding Rotary Box Pump Valves
By Paul Rumpf
Roger Kling asks about repair of the flap valves on a early Ampico A
rotary pump. I presume this is the typical four-bellows pump.
I have reconditioned a pump from a Simplex (?) system. This pump used
leather flap valves and these were turned up across the width of the
leather and did not seal correctly. To repair these flap valves I used
a sheet of aluminium cut to the required width. I used several tricks:
1. The aluminium material was that material used in offset lithography
printing/duplicating applications. The material is thin (maybe about
0.4 mm thickness).
2. To cut the material to width, I used a fine scribe and then parted
the strip by bending along the scribe line.
3. The strip was then coated with blotting paper I bought at a
stationery shop. I used contact adhesive, applied thinly and smoothly,
and pressed the two parts together under pressure using two sheets of
glass.
4. To attach the completed strip to the boards, I used the existing
wooden blocks fitted to the original leather strap.
The danger of using thin material is the tendency to distort from a
perfectly flat sheet. The printing sheets are _very_ flat; cutting
with scissors or knives will destroy the flatness.
Paul Rumpf
Melbourne
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(Message sent Wed 1 May 2013, 11:31:27 GMT, from time zone GMT+1000.) |
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