Hi! I’m Chad Wunderlich with Viking Pump and this is an internal gear pump. With each rotation of the gears, a set volume of liquid is moved from the inlet to the outlet. And if I were to reverse the direction of rotation, I reverse the direction of flow. Now this isn’t unique to internal gear pumps, other rotary pumps like external gear, lobe, and hose pumps exhibit this same behavior. But did you know it’s possible to make this internal gear pump deliver flow in just one direction, independent of the direction of rotation?

Packing is one of the most common and simplest seals for positive displacement pumps. Packing consists of braided or formed rings that are compressed inside the stuffing box of a pump. As the packing gland is tightened, the packing is compressed against the shaft and the inside of the stuffing box bore - creating a seal. When the pump is operating, process liquid cools and lubricates the packing. The pump must leak or "weep" slightly to ensure proper lubrication. Packing is one of the oldest forms of shaft sealing. Original packing was made of materials such as leather or rope.

In this Pump Report, Chad covers the causes and symptoms of positive displacement pump cavitation.

Hi, I'm Chad Wunderlich with Viking Pump. In a previous video we discussed the priming capability of positive displacement pumps, like this gear pump. This is due, in part, to the pump's ability to develop vacuum...but what happens if that vacuum gets too high? 

Today we're going to talk about cavitation. You're watching the Pump Report. 

In a positive displacement pump, each rotation of the shaft and gears carries a fixed volume of liquid from the supply tank to the downstream piping. When paired with an AC induction motor, speed and flow are very consistent. But what if you want to CHANGE the flow? In this episode of the Pump Report, Chad discusses controlling your positive displacement pump's motor with a variable frequency drive - or VFD.