197/257 Series Bushing pumps/motors

197 Series
	257 Series

The P197/P257 series is a series of high performance gear pumps. This completely new design utilizing computer aided engineering has allowed Permco to develop a state of the art external gear pump for heavy duty, high performance mobile applications.

Utilizing specialized sleeve bearing technology, gear journals are supported via a hydro-dynamic film, thus allowing continuous working pressures up to 4500 psi (310 bar) dependent upon the series and the selected gear size. At rated speeds up to 2400 rpm, the series is compatible with all mineral based hydraulic oils and some fire resistant fluids (water glycol and invert emulsions). Employing high strength iron for all pump body components and an all doweled construction, the P197/P257 is well suited for high pressure and high shock load applications.

Internal to the P197/P257 are its patented pressure balanced bronze thrust plates. Being of the floating type, the thrust plates are allowed to move freely, providing a positive seal across the entire face of its mating gear set and ensuring optimum volumetric performance at the highest operating pressures.

The P197/P257 gears are made from a high quality nickel alloy steel that ensures minimal gear flexure at high operating pressures. By using such a steel, the P197/P257 can be operated over a broad range of working pressures without the ensuing gear wipe of the housing at high pressures that can seriously detract from the volumetric output at lower working pressures.

The series is available in both single and multiple gear housing configurations with a variety of drive shaft and porting options. Depending upon the application, the use of Permco's P3000 series continental drive shafts may be applied to the P197 series.

Fluid Type, Temperature And Inlet Conditions
The P197/P257 series pumps are compatible with mineral base, water glycol and invert emulsion fluids. It is recommended that a premium quality hydraulic fluid with a viscosity range of 150-300 SUS (32-65 cSt.) at 100° F (38° C) be used to assure optimum performance. The normal operating viscosity range is between 55-1000 SUS (9-220 cSt.) with a not to exceed start up viscosity of 2000 SUS (440 cSt.).

Under normal operating conditions, fluid temperatures should not exceed 180° F (82° C) for mineral base fluids and 135° F (57° C) for water glycol and invert emulsions. If temperatures greater than these values are required for a particular application, please consult your Permco representative or call the factory.

Inlet conditions should not exceed 7 in. Hg. for mineral base fluids and 3 in. Hg. for water glycol and invert emulsions. Degassing of the fluid and subsequent cavitation may occur if these values are exceeded. For applications requiring inlet conditions greater than these values, consult your Permco representative or call the factory. Supercharging the inlet is not recommended.

Maximum operating speeds for all fluids and all gear widths is 2400 rpm. Maximum operating pressures are dependent upon gear widths and on the operating fluid. For mineral based oils, maximum operating pressures (dependent upon gear width and series) is 4500 psi (275.8 bar). For water glycol and invert emulsions, consult our Engineering Department.

Shaft Alignment
Unit shaft alignment must be within 0.005 inches (.127 mm) total indicator reading (T.l.R.) using a standard motor coupling. Follow coupling manufacturer's installation instructions to prevent end thrust on shaft. Turn pump shaft to assure freedom of rotation. Pump and motor must be mounted on a rigid base.

Side Loads
An outboard bearing is mandatory for radial (side or overhung) loads imposed upon the drive shaft of the pump. No axial (thrust) loading is permitted on the shaft.

Filtration (Mandatory)
To assure maximum performance and life, a 10 micrometre nominal return line filter with a Beta 10 rating of 2.2 is required for the system. Attempting to run the pump without proper filtration will degrade the shaft journals and journal bushings, causing premature failure. A 149 micrometre suction strainer is also suggested for added pump protection, however very high viscosities may dictate not using a strainer.

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