Pumps series BT and BTH are low speed gear pumps for transfering medium and high viscosity fluids, provided they have certain minimum amount of lubricating property, do not contain any solids and are chemically compatable with the materials of construction.
The standard material of construction for housing, bearing cover and stuffing box cover is grey cast iron. The shafts and gears are manufactured from case hardening steel, hardened and ground. The shafts are carried in plain bearings manufactured in bronze, with an option of sintered iron. The rotary shaft seal is a packed gland consisting of PTFE fillied aramid yarn, and the static sealing between mating parts is by means of either, liquid sealant or gaskets. All sealing materials are asbestos free. External axial loads are not permissable, restricted radial loads can be absorbed, dependant on their magnetude and direction. Driving by flexible shaft coupling is preferred. In the case of fluids which require elevated temperatures to flow i. e. bitumen, wax etc. the BTH series pump should be used. In this model the housing is double walled to provide a heating jacked.
The pump transfer chamber is heated by circulating heat transfer fluid or steam through the jacket. The standard range of models is complimented by a range of a special models described below. The pump size BT 2 can be supplied in a corrosion and acid - resistant construction (stainless steel body and gear) with carbone plain bearings bushes; the operating pressure of this pump is limited to 5 bars.