TM 10-6140-200-14
and they should project equally on each side of the
3-11. Replacing a Cell Cover
plates.
The specific methods used to seal cell covers to both
g. Before installing an element in a previously used jar,
the jar and the terminal posts vary with the manufacturer
wash out any sediment which may have accumulated in
and the system used. The techniques used to replace a
the bottom of the jar and clean all compound from
cover will be dictated by these different sealing methods:
around the inside of the top edge.
a. Sealing Compound and Lead Bushing Design. This is
probably the most commonly used system where an asphalt
h. Clamp the element, if necessary, when reinstalling it in
type compound is applied to seal the cover to both rubber
the jar. Make certain that the element is entering the jar
and plastic jars. Lead bushings, molded into the cover as
properly and that the plates are at right angles to the
plate support ribs in the bottom. When installing an
inserts, are welded or "burned" to the terminal posts to
element with a cell cover attached, use a putty knife to
prevent electrolyte leakage around the posts. When replac-
guide the lip of the cover past the top edges of the jar.
ing a cover of this type first cut the compound using a
warm putty knife. Cut the full depth of the cover adjacent
to the jar wall from corner to corner on each of the four
3-10. Replacing Cell in Battery
sides. Since reuse of covers, which have been removed from
a. Cells from which the elements were pulled, or which
the element, is not recommended, use a post trimmer to cut
off the post extensions above the cover. Break the lead
had damaged jars replaced, should be given an equalizing
charge and acid should be adjusted immediately following
bond between post and lead insert by driving the cover
repair before they are returned to service. (See Paragraphs
down approximately 1/32". The lead insert mold placed
2-10c and 3-12).
over the post and tapped with a hammer serves this
purpose. Remove the cover by inserting a hook through the
b. Before lowering a cell into a battery tray, be sure that
vent opening and lifting it off. Remove all sealing com-
it is correctly positioned relative to adjoining cells to
pound adhering to jar wall and neutralize these surfaces and
which it is to be connected. Cells must be connected in
upper portion of all terminal posts using a cloth moistened
with a soda solution. Thoroughly dry all of the neutralized
series with the positive side of one cell connected to the
surfaces. Install the new cover, complete cover to jar seal
negative side of the adjacent cell.
and reburn cell connectors as described in Paragraph 3-10.
c. When the problem has been corrected and the cell is
b. Sealing Compound and Seal Nut Design. This also
back in place in the battery tray, the cover must be
resealed to the jar. With the exception of those cells
has been a frequently used system. The jar to cover seal is
which contain a permanent jar to cover seal, a special
the same asphalt type sealing compound as used in the
asphalt type sealing compound is used for this purpose.
system described in Paragraph 3-11a above. The seal
Heat the compound until it melts, but do not let the
between the cover and the terminal post is accomplished by
temperature get above 435 degrees F. Pack any large
means of threaded seal nuts over the posts which tighten
openings between cover lip and jar wall with cold
against compression type soft rubber post gaskets. When
replacing a cover of this type cut the compound as
compound and then pour the hot compound into the
sealing groove in two steps. First pour the groove half full
described in Paragraph 3-11a. Assuming that the connectors
and soft flame with a torch to improve the adhesion; then
have been drilled off, unscrew all seal nuts, using a seal nut
fill the groove and flame again. Allow compound to cool
wrench, and remove the soft rubber post gasket. Lift the
and trim excess.
cover from cell with a hook inserted into the vent opening.
Clean and neutralize the jar walls and terminal posts as
described above in Paragraph 3-11a. Wipe the surfaces of
d. After sealing, pressure test cells for 10 seconds at a
the new cover with a clean cloth and place into position.
maximum of 1.5 P.S.I. and reinstall intercell connectors
by welding or "burning" them to the terminal posts. A
Clean the seal nut grooves by removing any old no-ox-id
small hot flame is recommended such as is available from
grease. Replace rubber gaskets and seal nuts. Tighten seal
a standard commercial burning torch using natural gas and
nuts with special wrench to prevent them from loosening.
oxygen or propane and oxygen. Carbon burning outfits
Renew the no-ox-id grease by melting it and pouring into
are also acceptable. These are available from the battery
the grooves at the top of the seal nut. Reseal cover to jar
suppliers. (See General Services Administration's Federal
and reinstall intercell connectors as described in Paragraph
Supply Catalog as referenced in Paragraph 3-5).
3-10.
CAUTION
c. Epoxy Seal and Seal Nut Design. This is one of the
newer systems which employs an epoxy or permanent, hard
Always be sure the cells are purged of gas, as
seal between cover and jar. The cover to the post seal is
identical to that described in Paragraph 3-11b above. To
explained in Paragraph 3-6, before using an
open flame or burning arc on top of the
disassemble a cell of this design requires that the jar be cut
battery.
and that both jar and cover be replaced. When reassembling
3-6
