Insane Hydraulics

Site theme image

Danfoss Series 90 Pump Filter Manifold With Thermal By-Pass Valve

While everybody is familiar with standard filtration options for the Danfoss series 90 end covers, (i.e suction, integral and remote) - this filter manifold is "special" and carries some features that may not be familiar to all technicians.

It is mounted on a special end cover with a bolt-on interface, and aside from being a standard spin-on cartridge "carrier", it is also prepared for charge flow cooling and carries the thermal bypass valve, cooler connection ports, and to top it off - a clogging indicator and a filter bypass.

Its "star feature" is the thermal valve that will bypass the radiator flow until a certain temperature is reached (see the schematic), allowing the circuit to reach optimum temperature fast. The thermal valve is a simple wax motor, that pushes the small rod out when the material inside the bronze housing expands.

Whenever you come across such an option, make sure to check the function of the thermal valve - when you heat it - the rod must come out. A faulty thermal valve can cause overheating, which is especially dangerous in the case of compact circuits that use the pump's case as an oil tank.

Also, the clogging indicator poppet is driven by a magnet, and therefore when dirt accumulates inside the small hole it's lodged in, it gets stuck, so make sure to keep it clean.

The manifold is also equipped with a charge pressure measuring port, connected to the line that feeds the closed-loop (i.e downstream the filter).