An ANSI B29 Subcommittee was established in 1975 to develop a standard
which would aid
municipalities and others in specifying chains for water and sewage
treatment plants. This Standard
is the result of that effort.
Previous ANSI chain standards have covered dimensions which assured
interchangeability and listed
ultimate strengths. This Standard serves a dual purpose. It was
developed to assure consistency
with previous standards and does replace ANSI B29.13-1972. However, it
also contains a
supplementary section which is unique to ANSI B29 standards. The
supplement identifies "Engineering
Characteristics" of 700 Class Welded Steel and Cast Chain including
attachments and sprockets in
common use for rectangular straight line collectors in water and
sewage treatment tanks.
"Engineering Characteristics" as used in this Standard identify those
properties of the chains,
attachments and sprockets which are required to assure that they will
Use of this Standard and supplement offers sufficient information to
use as a minimum or base
requirement when specifying chain attachments and sprockets for water
and sewage treatment plants.
The Standard specifies a minimum chain "quality". The user must
identify those options, not
affecting chain "quality", but which do describe the chain features
for a specific application.
User specifications should include the following:
- Chain type and number
- Attachment and spacing
- Pin and cotter or riveted
- Pearlitic malleable-cast chain
- Heat treated or nonheat treated (welded steel chain only)
- Destructive tests, if any
- Sprocket construction details
- Special materials or plating
- Shipping Instructions
In the event that any chain, attachment or sprocket produced in
accordance with this Standard does
not comply with the listed "Engineering Characteristics" of the
supplement for new and unused
chain, it would be anticipated that the supplier would like an
appropriate corrective action.
The function of the chains in a collector tank is to remove the
separated solids from the tank by
means of moving scraper flights. The operating conditions are both
corrosive and abrasive to
varying degrees. Successful past operation suggests that adherence to
Characteristic" will provide satisfactory operation of chains in this
application. Further, it
provides for similar operating results with chains from various
Historically, small amounts of copper have been added to materials
used in cast and fabricated
steel chains for this application. While it is reported in scientific
literature that small
additions of copper enhance resistance to atmospheric corrosion, it is
as yet undetermined whether
the benefits of this practice apply to this application, and
therefore, no requirement for copper
The subcommittee encourages comparison testing where additional data
is desired to confirm the
advantage, non-advantage or disadvantage of copper addition.
Additional consideration was also
given to the commercial problem of the unavailability of copper in
wrought steel materials except
for very large orders.
This Standard was approved by the B29 Standards Committee and was
subsequently approved by the
secretariat and submitted to the American National Standards Institute
for designation as an
American National Standard. This was granted on April 3, 1981.
The current revision was approved as an American National Standard on
March 8, 1996.