This is how a standard sewage collection system functions. Water flows (by gravity) into a network of (sloped down) drain pipes at the initial point of discharge, eventually intercepting a larger main pipe.
This water will eventually have to be transported to a sewage wastewater treatment plant. In some cases, the lift ranges from a few feet to hundreds of feet. Some methods can be used to help with the eventual lift. We’ve outlined the various beats for lifting water for your systems in this article.
- Archimedes Screw
This is the oldest known pumping method and is still in use today, although the method is somewhat outdated. Despite its being outdated, however, it has its advantages embedded in it. First, it’s simplicity with seals or packing to worry about.
However, a significant disadvantage big the Archimedes screw is the amount of space required to accommodate the necessity of the low angle of incline, which also increases weight substantially. Removal of the unit for maintenance is also difficult due to weight and accessibility.
- Self-priming centrifugal pumps
These are used in applications with relatively low flow rates, typically less than 1,000 GPM. As with any other pump, it has some advantages and disadvantages. Maintenance is straightforward because the pump is surface mounted, and trash can be removed via access ports on the casing side. The following methods are used to prime the system: foot valve, check valve, or additional vacuum pump evacuation of the inlet air.
A significant disadvantage is that the vacuum pump increases the system’s complexity. However, if these issues are addressed and pumps are adequately maintained and regularly, reliable operation results.
- Vertical sump design
This solves priming problems by submersing the pumping element underwater. A long shaft connects it to a surface-mounted electric motor, keeping it from getting wet. Maintenance of packings or seals is easy since the pump does not need to be pulled for repacking service. However, with a long shaft comes the alignment problem, unbalance or wear of the line bushings.
- Submersible (wet) pumps
These types feature an electric motor directly coupled to a pump, resulting in a compact and lightweight unit that is well suited for relatively shallow wet wells (10-20 feet) with horsepower typically less than 30 hp. While submerging the motor is advantageous on the one hand, it can also be a source of trouble on the other.
Submersible pump motors typically feature higher-quality stator windings than dry, surface-mounted motors. Even after being flooded, the windings continue to operate normally for some time.
Additionally, moisture sensors that detect, warn, and alarm are included. Sadly, many operators either do not have these connections or disconnect them to avoid nuisance alarms, putting the units on a path toward eventual undetected failure.
- Submersible (dry) pumps
While they are similar to wet submersibles, they are installed in dry wells and connected to wet wells via suction piping. With more accessible and cleaner access, servicing and pulling such pumps for maintenance is more manageable.
A common disadvantage is that cooling the motor is no longer accomplished by submerging it. Thus, dry submersibles require a portion of the pumpage circulated through the motor housing’s cooling passages. This clogs these passages with dirt from the pumpages, resulting in motor overheating.
- well sewage pumps
To justify the cost of constructing a dry well adjacent to a wet well, along the shaft, or to avoid flooding the motor windings. This arrangement is similar to any other surface-mounted pump, with shafts connected vertically to the motor shafts.
For dry wells, packing or mechanical seals are a personal preference, similar to those made for standard surface-mounted pumps. The primary concern is that the pumping station as a whole could be flooded. Dry-design motors frequently fail, making corrective action difficult until the entire station is pumped out during an emergency.
- Dry well U-Jointed shafting pumps
The dry well solves the problem of possible flooding. However, lubrication of the U-joint bearings as well as the pillow blocks is essential. If proper preventative maintenance procedures are not followed, high vibrations and failures will become the norm, not the exception.
Conclusions are recommendations
Lifting water to the surface can be accomplished in various ways, each with its own set of benefits and drawbacks. While the ultimate goal is to have the most efficient system, each option should be evaluated on its own merits.
It is also critical not to treat your pump system as if it were a one-time installation. Understand operational and underlying principles of operation, and perform proactive maintenance. You can also reduce or even eliminate unexpected failures.
Pump House collaborates with you to determine which method is best for you before recommending one of our world-class Grundfos pumps.
Contact us today or set up an appointment with one of our experts to discuss your pump requirements. Your water is only a pump away from being lifted!