The pump curve is for stable flow only. Pumps starting are not on the curve. That being said, the pump will move from zero head and zero flow to high flow and low head to stable flow and head depending on the system curve. The time it takes for the flow to stablize is dependent on the system.
This design is normally only seen in slurry pumps. It is to remove material from the area arround the seal. It should never provide a vacuumn as you could draw air into the pump. Sometimes they are designed to maintain high ciculation arround the shaft and seal.
The torque on your motor is rated at full speed at 50hz. See if your VFD can operate at a constant torque mode. That should give you more power at your lower speeds.
First, operation of a motor at 8hz is not recomended. Motors are designed to operate at 50hz and do not provide full torque at low speeds. Here is some detailed information on motor operations. Th only way to increase the torque is to speed up the motor. You will have to put a different gear...
This is a very interesting thread. Based on the information provided, the energy savings of going to a larger more efficent pump could exceed $100,000 per year.
I would recommend by passing the the loble pump and filling the tank with just the centrifugal pump. The lobe pump is likely sized to operated a slurry injection system on the wagons. This requires higher pressures and lower volumes. The maximum flow rate will be based on the lobe pump which...
Performace testing is carried out as per API standards, not real service conditions. Real life service conditions rarely match factory testing environments. Any information on testing proceedures or bench marks will be found in the API standards. The latest standards are available from API...
These are all types of bearing lubrication. They will make up parts of the bearing housing and are dependant on the type of pump, speed, temperature, and location.
I have a client that is looking for a pump to inject brine into a deep disposal well. The duty point is 30m^3/h at 6200 kpa (132gpm@2075') with a SG of 1.05 brine at 60oC.
Thanks
A selection to the right of the BEP is more common when you are operating the pump with a drive on a pump that is normally operating below the design capactity. If the pump is normally going to operate at the design point, this pump will have less ability to operate if the system curve is...
Roughness is entirely dependant on your application. In one case, pipe roughness is a function of friction or in the case of milk, it is a function of surface adhesion of bacteria.
You will have to watch the wear on the downstream valve as they are not designed to throtle flow on a continuous basis. The wear goes up with more material you are pumping in the fluid. More information for your consideration.
You can not get a motor that will operate at 750rpm. To get your speed control look first to a belt and pully system. This will allow you to match the pump speed to your application and allow you to change the pump speed reasonably easy. A gear drive option followed by a VFD are your next...
Multi-Stage vertical pumps come in many sizes and from many manufactures. The vertical turbine is one type of application. Normally the Vertical multi stage pumps refers to a multi impeller pump in vertical configuration. The pumps selling features are that they have a small footprint. These...