Dixon 3000 Serie Mode D'emploi

Note: Absolute flapper sealing is not a necessity, as these valves are
designed to prevent back filling by product. Metal-to-metal seals will always
have minor air leakage around the flapper. In a backfill situation the product
would quickly plug these minor voids and prevent any further passage of
product.
Spring and Rubber Seal Options:
a) The vast majority of swing checks are purchased with a free swing, all
metal flapper (metal-to-metal seal) and for mounting in the horizontal
position. Some fleets specify spring-loaded flappers and others with a
rubber-to-metal seal and yet others with both options.
b) Springs keep the flapper closed when the blower is "not" operating and
prevent flappers from vibrating and "clanging" against the body when
traveling. Spring-loaded flappers may also allow for vertical or angular
installation (check with factory) not possible with spring-less valves.
However, some fleets are not comfortable with a flapper spring and
complain that there is some loss (although considered minor) of line
pressure to overcome spring tension when unloading.
c) The rubber seal (on the flapper) option is sometimes requested because
it is thought that a tighter seal is provided with a rubber-to-metal design.
Free swinging, rubber-seal flappers will also be quiet (no clanging) on
the road. However it is mostly the rubber seal customers that request the
spring-loaded flapper believing that a better seal is provided when both
options are incorporated. Seal materials offered can include; Buna,
Silicon, and white food grade elastomers.
Inspection Frequency: Swing check valves should be routinely inspected
as part of a preventative maintenance schedule for dry bulk tankers.
The units should be given at a minimum, a visual/manual inspection,
every 2-3months. The cleanout cap should be removed and
inspected. The cap threads should be coated with a thread anti-
seize compound before reassembly. This will prevent the caps from
becoming stuck due to corrosion and prevent the body from
cracking.
DIXON BAYCO WARRANTY: For Complete warranty information, Please
refer to the inside back cover of the latest Dixon catalogue.
090063 Rev 8