Abstract: A system for testing drilling mud includes viscosity measuring tubes and other instruments for testing the parameters of drilling mud. The mud is heated to an elevated temperature and recirculates in a closed flow path which includes the measuring instrumentation. A diaphragm pump successively withdraws a column of mud from the flow path and discharges mud into the flow path to effect the recirculation. A pumping column between the flow path and the pump contains a column of drilling mud which thermally isolates the pump from the hot mud in the flow path.

Abstract: In a system for testing drilling mud, a mixing tank and an aging vessel are hydraulically connected to supply drilling mud to a closed recirculating path through which mud is pumped to measuring instrumentation. The accumulator has a head which is removable for inspection and maintenance of the gas pressurized piston which pressurizes the drilling mud. The seals on the head are positioned to minimize wear.