Construction details[ edit ] The steel housing of the seat valve pump contains four hydraulically controlled seat valves, two suction and two delivery valves for the two hydraulic cylinders. The suction and discharge valves are synchronized with the hydraulics of the delivery pistons - this ensures that the contents of the delivery cylinder is equal at all times to the volume being pumped. Once the "sucking" piston reaches its end position, the corresponding suction or delivery valve is simultaneously closed or opened.
If you need more flexibility you can install another pump and operate it in either series or parallel with the first pump.
Two similar pumps, in series, operate in the same manner as a two-stage centrifugal pump. Each of the pumps is putting energy into the pumping fluid, so the resultant head is the sum of the individual heads.
Some things to consider when you connect pumps in series: Both pumps must run at the same speed same reason. Be sure the casing of the second pump is strong enough to resist the higher pressure. Higher strength material, ribbing, or extra bolting may be required. The stuffing box of the second pump will see the discharge pressure of the first pump.
You may need a high-pressure mechanical seal. Be sure both pumps are filled with liquid during start-up and operation. Start the second pump after the first pump is running. Some things to consider when pumps are operated in parallel: Both pumps must produce the same head this usually means they must be running at the same speed, with the same diameter impeller.
Two pumps in parallel will deliver less than twice the flow rate of a single pump in the system because of the increased friction in the piping.
The shape of the system curve determines the actual increase in capacity. If there is additional friction in the system from throttling see dotted line in the following diagramtwo pumps in parallel may deliver only slightly more than a single pump operating by its self.
If you run a single pump only, it will operate at a higher flow rate A than if it were working in parallel with another pump B because it will be operating further out on the curve requiring increased power. The rule is that if a pump is selected to run in parallel, be sure it has a driver rated for single operation.
Most plants read only total flow and cannot see the differences in individual pump performance Parallel pumps are notorious for operating at different flows. Often a weaker pump is operating close to its shut off point while a stronger pump is operating to the far right of its curve and running out of NPSHA.Pumps operating in series Pumps operating in parallel To connect two pumps in series means that the Figure 15 presents a parallel configuration of discharge from the first pump is piped into the inlet two pumps.
For many young process engineers the concept of multiple centrifugal pumps in series or parallel is often confusing. Today's blog entry tries to explain the concept of centrifugal pumps in series and parallel.
Variable Speed Pump Selection - Parts 1 - 3 This tutorial takes a different approach to pump selection for VFD operation.
Part 1 addresses constant pressure / variable flow while Part 2 addresses variable pressure / variable flow. When paired with the Bell & Gossett e and e hydraulic pumps, the Technologic PPS parallel pump controller allows you to set up a parallel pumping system – .
Series and Parallel Pumps Demonstration Unit Centrifugal pumps are often used together to enhance either the flow rate or the delivery pressure beyond that available from the single pump. The FM51 is designed to demonstrate the operational advantages of parallel or series operation.
Centrifugal Pump. A centrifugal pump is one of the simplest pieces of equipment. Its purpose is to convert energy of an electric motor or engine into velocity or kinetic energy and then into pressure of a fluid that is being pumped.