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Work order: Calculating a gear pump
A cylinder (4000/150/50) should extend at a speed of 0.02 m/s. Your work order is to select the right pump from the manual, which can deliver the necessary volume flow. The longer the system is in operation, the more the volumetric efficiency of the pump will deteriorate. Furthermore, you do not want to operate the pump at its performance limit. Therefore, multiply a safety factor of 1.2 to your result.
The pump is driven by a three-phase asynchronous motor, whose nominal speed is 1440 /min at 50 Hz mains voltage.
Download the manual as pdf here: Learnchannel manual gear pump.pdf
Required volume flow of the cylinder:
QCyl = A * v = Π (0,15 m)2/4 * 0,02 m/s = 21,206 l/min
With a safety-factor of 1.2: QPump = 1,2 *21,206 l/min = 25,45 l/min
Q = n * V => V = Q / n = 25,45 l/min / 1440 min-1 = 17,67 cm3/rev
chosen: Type 19
Note: This manual does not differentiate between Qth and Qe, nor is there any volumetric efficiency. The user is particularly interested in what the pump "delivers" at the outlet, so the volume flow Q in the manual is to be understood as the effective volume flow.