Flowserve 955 Chemiepac - Manual (Page 3)

Installation, Operating and Maintenance Instructions Chemiepac Mechanical Seal
1.0 BRIEF DESCRIPTION, FUNCTION
1.1 Specifications for the operations described herein:
Application limits
Product pressure p (bar) depending on temperature see catalogue
Speed v (m/s) 8
Product temperature t (°C) to 125° C type 970...
to 100° C type 950...
The application limits specified are maximum load values and assist in preselection.
The application limits must be checked for every application.
A warranty in an individual case is possible only when FLOWSERVE knows the exact
application conditions and these have been confirmed in a separate agreement.
1.2 Surface temperature of seal faces:
The temperature class as per EN 13463-1 is based on the expected surface tempe-
rature of the faces. The difference between the medium temperature and the surface
temperature of the faces depends on various factors.
The annexed diagram shows how the temperature class can be calculated on the basis
of a temperature difference obtained in practice.
1.3 Brief description
The CHEMIEPAC is a partially assembled mechanical seal system designed to seal
rotating shafts with respect to stationary housings, e.g. a pump shaft with respect to
the housing.
The CHEMIEPAC consists of two units:
The stationary unit is the mating ring (4) with corresponding flat gasket (5). One face
of the mating ring is designed as a seal face, the opposite face is marked “no seal
face”. The mating ring and flat gasket must be connected tightly to the pump housing.
The rotating unit comprises the components 1-3, 6-10, 14 and 15 for the CHEMIEPAC
955, 956 and 958, and 1-3, 6-15 for the CHEMIEPAC 970, 971 and 978. The main
component is the elastic bellows of PTFE that the two-part drive bolts tightly and free
of twisting to the shaft. The face of the bellows is designed as a seal face.
Near the seal face the mechanical properties of the PTFE material are enhanced by
additives. An exchangeable seal ring is available for the CHEMIEPAC 970,971 and 978.
A spring plate (6) is locked along the axis and free of twisting with the bellows and
has built-in springs (3) that are supported in the axial direction against the drive. In
the installed state, the seal faces of the stationary mating ring and the seal face of the
bellows form the seal gap through mutual elastic contact. The medium is sealed from
the atmosphere at the seal gap. The sealing effect is generated by the bellows’ spring
pretension and reinforced by the hydraulic closing force arising from the pressure
exerted by the sealing medium.
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