Industry
Waste Water Treatment
Open impellers, polymer wetted parts and vertical sump pumps for screened sewage, return sludge, effluent and pit drainage.
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VNP Series
VNP Vertical Sump Pump
Vertical single-stage sump pump in polypropylene for wet-pit installation with solids to 20 percent
Overview
A sump pump has no flooded suction to protect it and no easy access once it is in the pit. Both facts drive every decision in the VNP design.
The VNP is a vertical, single-stage sump pump designed specifically for water and waste water duties. Its wetted parts are polypropylene and its construction follows the back-pull-out principle of ISO 2858.
It is built for wet installation: the pump hangs in the sump with the column submerged and the bearing and drive above the liquid level. That removes the suction lift problem that limits a horizontal pump on a pit duty.
The solids content limit is approximately 20 percent, the highest of any pump in the Flowsteer range, and the sealing uses a labyrinth seal or a lip ring seal rather than a mechanical seal — the right choice where a mechanical seal would be flooded and unserviceable.
VNP vertical sump pump in polypropylene with long column and discharge elbow
Key Benefits
What This Pump Does Better
- Built for wet-pit installationThe pump is designed to hang in the sump, so there is no suction lift and no priming problem on a pit duty.
- Highest solids tolerance in the rangeApproximately 20 percent solids content, twice the KCP limit, for sumps that collect grit and debris.
- Polypropylene wetted partsPP resists the mixed chemistry that collects in an industrial sump and would corrode a metal column.
- Labyrinth or lip ring sealingNon-contact and lip sealing suit a submerged duty where a mechanical seal cannot be inspected or flushed.
- Back-pull-out construction to ISO 2858The rotating assembly follows the same maintenance logic as the horizontal ISO pumps.
- Grease-lubricated bearings above the liquidBearings sit clear of the sump, where they can be greased and monitored.
In the Works
The Pump and How It Is Built
Application Scenarios
Where This Pump Is Put to Work
- Industrial sumps and collection pitsEmptying pits that collect washdown, spillage and process drainage.
- Waste water pump stationsLifting waste water out of a wet well where a flooded-suction pump would not fit.
- Drainage duties with gritPit duties carrying up to roughly 20 percent solids.
- Chemically mixed sump contentsPP wetted parts for sumps whose contents vary and cannot be pinned to one analysis.
Who It Is For
- Plant maintenance teams responsible for sumps and collection pits that a horizontal pump cannot serve.
- Waste water contractors specifying wet-well pumps for stations with grit-bearing flow.
- Industrial sites whose sump contents are chemically mixed and unpredictable.
Problems It Solves
What It Is Chosen to Fix
- A horizontal pump that will not prime on a pitA vertical wet-installed pump has no suction lift to overcome.
- Grit destroying a clean-water pumpRoughly 20 percent solids tolerance is built into the selection, not stretched to fit.
- Mechanical seals failing under the liquid lineLabyrinth and lip ring sealing replace a seal that cannot be flushed or inspected in a sump.
- Corrosion from unpredictable sump chemistryPolypropylene wetted parts do not depend on knowing the exact analysis.
- Bearings drowned in the pitGrease-lubricated bearings sit above the liquid level where they can be serviced.
Technical
Features and Specifications
Every value below is taken from the Flowsteer product catalogue. Values the catalogue does not publish are marked TBC rather than estimated.
Technical Features
- Vertical, single-stage construction
- Back-pull-out design according to ISO 2858
- Wet installation
- Closed impeller
- Grease-lubricated bearings
- Labyrinth seal or lip ring seal
- Polypropylene wetted parts
Specifications
| Pump type | Vertical, single-stage sump pump |
|---|---|
| Construction | Back-pull-out according to ISO 2858 |
| Installation | Wet installation |
| Impeller | Closed |
| Bearing lubrication | Grease |
| Ambient temperature | -20 °C to 60 °C |
| Operating temperature | Up to 80 °C |
| Solids content limit | Approximately 20 % |
| Sealing | Labyrinth seal or lip ring seal |
| Materials | PP |
| Capacity | TBCnot published on the source catalogue |
| Head | TBCnot published on the source catalogue |
| Column length | TBCconfirm against sump depth at enquiry |
Materials
Wetted Materials and What They Are For
- PolypropyleneThe published wetted material for the series. PP covers the mixed and variable chemistry typical of an industrial sump.
- Labyrinth sealA non-contact seal with no rubbing faces to wear, suited to a submerged duty that cannot be inspected.
- Lip ring sealA contact lip seal, chosen where a positive barrier matters more than zero wear.
- Metal alternativesWhere the sump contents are known and non-aggressive, ask us whether a metal column is available for the duty.
Customisation
What You Can Specify on This Pump
- Sealing: labyrinth seal or lip ring seal
- Column length confirmed against the sump depth
- Support plate and discharge arrangement to suit the pit cover
- Drive selection for the duty and the available headroom
Certifications, production capacity and export markets are not published in the Flowsteer catalogue, so this site does not state them. Tell us what your project needs evidenced and we will confirm in writing.
How It Compares Within the Range
| Series | Published Envelope | Best Suited To |
|---|---|---|
| VNP Vertical | PP, vertical wet installation, approximately 20 % solids | Sumps and wet wells with grit-bearing flow |
| KCP Series | PP, PE or UHMW-PE, horizontal, approximately 10 % solids | Flooded-suction duties on corrosive water |
| ANSI CN Series | Metal, horizontal, full open impeller | Solids-bearing water on a flooded suction with an ANSI footprint |
Use Guide
Getting This Pump Right on Site
- Measure the sump depth from the mounting plate to the lowest liquid level before ordering; the column length has to be confirmed for each installation.
- Check the operating temperature against the 80 °C limit — PP loses strength well before it deforms visibly.
- Keep the pump clear of the sump floor so settled grit is not drawn straight into the impeller.
- Grease the bearings on the published interval. They sit above the liquid and are the one part of a sump pump that can be serviced without lifting it.
- Do not run the pump with the column out of the liquid. A wet-installed pump relies on the pumped liquid for cooling.
Related
Industries Solutions and Guides
Industry
Industrial Water Transfer
Plant water, process circulation, booster and liquid transfer duties across the full Flowsteer size band.
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Solution
Sealing and Bearing Solutions
Mechanical seals, gland packing, labyrinth and lip ring sealing, and where each belongs across the Flowsteer range.
Read moreSolution
Pump Material Selection
Cast iron through to UHMW-PE. How the Flowsteer range maps onto water that ranges from clean to chemically hostile.
Read moreInstallation Guide
Vertical Sump Pump Installation
A wet-installed pump removes the suction problem and replaces it with a set of geometry problems. All of them are solved before the pump is ordered.
Read moreMaterial Guide
Pump Materials Guide
Grey iron through to UHMW-PE. What each wetted material is for, and the failure it is chosen to prevent.
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Maintenance Guide
Operation and Maintenance Tips
A short list of the things that actually decide how long a water pump lasts, drawn from how these pumps are built rather than from general advice.
Read moreAlso in the range
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View specificationsQuestions
VNP Vertical Sump Pump FAQ
What does wet installation mean for a sump pump?
The pump column and impeller sit submerged in the sump while the bearing housing and motor stay above the liquid on a support plate. There is no suction lift and no priming, which is why a vertical pump suits a pit duty that a horizontal pump cannot serve.
How much solids can the VNP handle?
Approximately 20 percent, the highest published figure in the Flowsteer range. If your sump collects grit and debris, this is the series to look at first.
Why a labyrinth or lip ring seal instead of a mechanical seal?
A mechanical seal under the liquid line cannot be inspected, flushed or adjusted. A labyrinth seal has no rubbing faces to wear and a lip ring seal can be renewed when the pump is lifted. Both are better suited to a submerged duty.
What capacity and head does the VNP deliver?
The source catalogue does not publish capacity and head for this series, so we mark them TBC rather than guess. Send us the sump depth, the flow you need and the discharge head and we will confirm the selection.
What column length can you supply?
Column length is made to the sump depth and is confirmed at enquiry. Measure from the mounting plate face to the lowest working liquid level and send that figure with the enquiry.
Is the VNP available in materials other than PP?
PP is the published wetted material for the series. If your sump contents are known and non-aggressive, ask us whether a metal column can be supplied for that duty.
Request a Quotation for the VNP Series
Send the duty point and the liquid description and we will confirm the size, the materials and any specification this page marks TBC.