SP Engineering manual

Summary

Product Identification

This document is an engineering manual for Grundfos SP pumps, which are designed for durability, efficiency, and construction using thin-plate stainless steel.

Available materials for SP pumps include:

• Stainless steel EN 1.4301/AISI 304
• Stainless steel EN 1.4401/AISI 316
• Stainless steel EN 1.4539/AISI 904L

Applications

Grundfos SP pumps are suitable for a variety of applications:

• Freshwater Supply: For drinking water, irrigation, and industrial uses.
• Dewatering: Including mining applications and construction sites.
• Horizontal Application: Pumping from tanks or reservoirs, often for fountain applications.
• Corrosive Water: Such as seawater for fish farming, offshore industrial uses, and reverse osmosis feed.
• Hot Water and Geothermal Water: Where water temperatures are elevated.
• Booster Modules: As part of booster systems.

Operating Conditions & Limits

Feed Water Characteristics

• Groundwater: Typically 25 to 10,000 years old, generally of high quality requiring little to no treatment. Pollution-free aquifers can be larger than 600 km².
  • Drinking water extraction should target older groundwater at pollution-free depths.
  • Irrigation wells may use water from upper aquifers with slightly polluted quality.
  • Permanent lowering of groundwater levels can lead to increased salinity and other undesired substances.
• Riverbank Filtration: Filters river water through the ground, providing a natural reduction of human-induced enzymes, viruses, bacteria, and pathogens (up to 90%).
• Surface Water (Freshwater): From lakes or rivers, requires treatment due to exposure to nature and human activities. Water level and quality vary seasonally; solids and abrasive minerals should be settled or screened before pump intake.
• Surface Water (Seawater/Saltwater):
  • Coastal intake should be placed where the lowest salt content is expected, potentially hundreds of meters from the splashing zone for capacities exceeding 1,000 m³/h.
  • For capacities lower than 1,000 m³/h, corrosion-safe beach wells and coastal bank filtration wells are recommended.
• Air/Gas in Water: Can cause pump underperformance or stoppage. Solutions include deeper pump submergence, installing a sleeve around the pump (below the inlet, not above dynamic water level), or creating a vacuum in the well casing for high gas content.
• Water Temperature: In the absence of geothermal influence, groundwater temperature increases 2 to 3 °C for each 100m of well depth.
• Solids Content: Water containing 10 mg/l solids is referenced in service interval guidelines. Sand-free water is also mentioned.

Corrosion Resistance

• Pitting Resistance Equivalent (PRE): Used to compare corrosion resistance of stainless steel.
  • PRE = (% Cr) + (3.3 x %Mo)
  • For stainless steel types containing Nitrogen (N): PREN = (% Cr) + (3.3 x %Mo) + (16 x %N)
• Corrosion diagrams (figures 17 and 18 in the official PDF) illustrate the relationship between chloride [ppm] and temperature [°C] for different stainless steel types (EN 1.4301, 1.4401, 1.4539) and their respective models (SP, CRN, SPN, SPR). These diagrams indicate areas of high corrosion risk versus little or no corrosion risk for various water types (freshwater, brackish water, seawater, mining waters).
• Elastomer components may be damaged by poor water quality (e.g., high hydrocarbons/chemicals); FKM rubber can be specified.
• Corrosion protection in seawater can involve cathodic protection systems (galvanic or impressed current).

Well & Pumping Dynamics

• Well Yield: Each well has a specific capacity (m³/h per meter of drawdown).
  • Overpumping can lead to deep drawdown, oxidation, ochre formation, clogging, and reduced well life.
  • Overpumping can also lower aquifer water levels, causing chemical changes, heavy metal precipitation, and infiltration of nitrate/pesticides.
• Drawdown:
  • At moderate flows, drawdown is nearly linear (e.g., 1 m³/h increase in water results in approx. 10 cm/m³ drawdown).
  • At large flows, drawdown becomes parabolic due to progressively increasing frictional resistance.
• Service Intervals: Guidelines are provided in the official PDF (figure 9) to estimate service intervals, efficiency loss, and renovation costs based on water velocity, pump material, pumping environment conditions, and presence of solids or aggressive CO₂.
• Pump Performance: For dewatering, the duty point should be selected to the right of the best efficiency point to maintain performance and prevent clogging. Removing the non-return valve can enhance backwash.
• Horizontal Installations: A flow sleeve and baffle plate are recommended at low water levels. If multiple pumps are installed, the distance between them should equal the overall diameter of the pump and motor (including cooling sleeve).
• Number of Start/Stops: Submersible pumps have low inertia, allowing fast start/stop, ideal for fountain applications. Canned motors are recommended for high start/stop frequency; rewindable motors should not be used. High start/stop frequency impacts contactor lifetime.

Electrical & Controls

• Motor Types: General descriptions are provided.
• Motor Protection Devices: Mentioned as essential.
• Reducing Locked-Rotor Current: Various starting methods are discussed:
  • Direct-on-line (DOL)
  • Star-delta (SD)
  • Autotransformer (AT)
  • Primary resistor-type starter (RR)
  • Soft starter (SS)
  • Frequency converters (variable speed drive)
• Variable Speed Drives: Operation with frequency converters is covered, including the Grundfos CUE variable speed drive specifically for SP pumps.
• Power Supply:
  • Voltage: Considerations for voltage unbalance, overvoltage, and undervoltage.
  • Frequency: Mentioned.
  • Grid Connection: Mentioned.
  • Current Asymmetry: Mentioned.
• Cables: Motor cables, drop cables, and cable joints are discussed. The blue Grundfos TML motor cable is recommended in full length to the junction box on the surface for acidic waters.
• Phase-Failure Relay: Recommended between the overload relay and the motor to protect against contactor failure.

Mechanical & Installation Considerations

• Pump Setting: Mentioned.
• Pump and Motor Selection: Based on duty point, well diameter, well yield, pump efficiency, and water temperature.
• Derating of Submersible Motor: Mentioned in relation to water temperature.
• Protection Against Boiling: Mentioned.
• Sleeve Cooling: Mentioned.
• Riser Pipe Selection: Mentioned.
• Handling: Includes pump/motor assembly, cable splice/connection of motor and drop cables, and riser pipe connections.
• Pumps in Parallel Operation: Mentioned.
• Pumps in Series Operation: Mentioned.
• Pump Start Up: Mentioned.
• Generator Operation: Mentioned.

Communication & Monitoring

• SCADA Systems: General introduction to SCADA, its main parts, functions, and web-hosted options.
• Networking Basics: Covers networking topology, communications protocol, functional profile, and fieldbus.
• GENIbus: Grundfos' proprietary communication protocol, including background, technical description, and cabling guidelines.
• Grundfos GENIbus Products: Specific products for SP applications are mentioned.

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Disclaimer: This summary is based solely on the provided text extract. It may not include all figures, footnotes, or the latest revisions present in the complete OEM PDF datasheet. Contractual data must always match the specific OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror