Pumps Hi Lo Vivoil

P. HI - LO

P OMPE A LTA B ASSA PRESSIONE

VIVOIL OLEODINAMICA VIVOLO VIVOIL OLEODINAMICA VIVOLO

Dimensioning

The main purpose of the HI-LOW pump is to optimise power absorption during the operating cycle by in-creasing the opera ting speed during low-pressure operation. Data:

V LO V HI p LO p HI 10 Q LO Q HI ƞ v ƞ m n

[cc/rev] [cc/rev] [bar] [bar] [rpm] [bar] [l/min] [l/min] 0.9÷0.95 0.8÷0.9

= final pump displacement (low-pressure element) = pump drive displacement (high-pressure element) = maximum pressure with high flow and low pressure operation = maximum pressure with high pressure and low flow operation

= engine rpm

= final stage recirculation pressure (average value, depends on operating flow rates)

= flow rate of the final pump (low-pressure element) = flow rate of the drive pump (high-pressure element)

= volumetric efficiency = mechanical efficiency

Calculations:

T LO [Nm] = p LO x (v LO + v HI ) / 20 x π x ƞ m T HI [Nm] = (p HI x v HI + 10 x v LO ) / 20 x π x ƞ m T INT [Nm] = (p LO x v LO ) / 20 x π x ƞ m

= total torque absorbed in LOW PRESSURE phase = total torque absorbed in HIGH PRESSURE phase

= totale torque absorbed in final pump (low-pressure element)

Power absorbed:

Pm LO [kW] = (v LO + v HI ) x p LO x n / 600000 x ƞ m = power absorbed in LOW PRESSURE phase Pm HI [kW] = [(v HI x p HI ) + (v LO x10)] x n / 600000 x ƞ m = power absorbed in HIGH PRESSURE phase Total flow:

Q LO [l/min] = v LO x n x ƞ v Q HI [l/min] = v HI x n x ƞ v Q TOT [l/min] = Q LO + Q HI

= flow rate delivered by the final pump (low-pressure element) = flow rate delivered by the driving pump (high-pressure element)

= total pump flow rate with p < p LO

Limit value:

Q LO < 60 [l/min] (gr. 2) Q LO < 20 [l/min] (gr. 1) p HI = see pressure value P1-P3 on pump catalogue p LO = see valve calibration range

Maximum coupling torque gr.2 = 86.2 [N/m] Maximum coupling torque gr.1 = 42.8 [N/m] It is recommended to ALWAYS check: - torque absorbed by the primary shaft and intermediate coupling;

- T LO < T.2 max. permissible see table permissible torques for shafts - T HI < T.2 max. permissible see table permissible torques for shafts

- T INT < Maximum coupling torque - flow rate final pump (Q LO ) - Q LO < 60 [l/min] (gruppo 2)

Vivoil Oleodinamica Vivolo s.r.l- Società a Socio Unico- via Leone Ginzburg 2-4 40054 Budrio (BO) Italy tel: +39 051 803689 fax: +39 051 800061

5 www.vivoil.com- Italiano