Peristaltic (Hose) Pump

Peristaltic hose pumps transfer fluids by compressing a flexible hose with rotating rollers or shoes, creating a sealed chamber that moves liquid from suction to discharge without internal contact. The pump mechanism squeezes the hose progressively, generating positive displacement flow ideal for abrasive slurries, viscous chemicals, and corrosive solutions in municipal treatment applications. These pumps typically handle flow rates from 0.1 to 1,500 GPM with heads up to 200 feet, offering exceptional chemical compatibility and self-priming capabilities. However, the flexible hose requires regular replacement every 500-8,000 hours depending on application severity, creating ongoing maintenance costs that can exceed centrifugal pump alternatives.

• Polymer Feed Systems: Peristaltic pumps deliver diluted polymer (0.1-0.5%) to clarifiers and belt filter presses at 0.5-50 GPM. Selected for precise flow control and ability to handle viscous solutions without shearing polymer chains.
• Hypochlorite Feed: Sodium hypochlorite injection for disinfection at 1-15 GPM in smaller plants (0.5-5 MGD). Chosen because hose material contacts chemical while pump mechanism stays isolated from corrosive solution.
• Lime Slurry Transfer: Lime milk (5-15% solids) pumping at 5-100 GPM for pH adjustment in water treatment. Selected for ability to handle abrasive slurries without internal wear parts.
• Laboratory Sample Lines: Continuous sampling at 0.1-2 GPM for online analyzers. Provides consistent, pulsation-free flow essential for accurate measurements.

Daily Operations: Monitor flow rates via VFD display or external flowmeter. Check hose condition through sight windows for swelling, cracking, or deformation. Adjust speed based on process demands - polymer feed rates change with influent conditions. Log operating hours for maintenance scheduling.

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Maintenance: Replace hoses every 1,000-3,000 hours depending on application and chemical compatibility. Requires basic hand tools and 30-60 minutes downtime. Wear safety glasses and chemical-resistant gloves when handling polymer or chemical-wetted components. Most operators can perform hose changes with minimal training.

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Troubleshooting: Hose failure shows as flow loss, visible cracking, or chemical leakage. Pulsating flow indicates worn rollers or loose hose connections. Excessive noise suggests bearing wear or misaligned rotor. Typical hose life: 6-18 months for abrasive slurries, 12-24 months for polymers, 18-36 months for clean water applications.

• Hose/Tubing: Heart of the system - typically natural rubber, EPDM, or specialty compounds. Sizes range 0.5"-6" ID for municipal flows. Selection based on chemical compatibility and abrasion resistance.
• Rotor Assembly: Contains 2-6 rollers or shoes that compress hose against housing. Roller count affects flow smoothness - more rollers reduce pulsation but increase cost. Typical municipal units use 4-6 rollers for flows 5-200 GPM.
• Drive System: Variable frequency drives standard for flow control. Gear reducers provide torque multiplication. Speed ranges typically 10-200 RPM for municipal applications.
• Housing/Casing: Cast iron or stainless steel construction houses hose and rotor. Must withstand compression forces while allowing easy hose replacement. Quick-release mechanisms standard on units >10 GPM.

• Flow Rate: 0.1-500 GPM typical range for municipal applications, with most chemical feed applications in 0.5-50 GPM range. Accuracy ±1-2% of rated flow when properly calibrated.
• Discharge Pressure: Up to 150 PSI maximum for most municipal models, though 75-100 PSI more common for chemical feed applications. Suction lift capability typically 25-28 feet maximum.
• Hose Life: 1,000-8,000 hours typical depending on chemical compatibility, operating pressure, and duty cycle. Continuous operation reduces life compared to intermittent service.
• Turndown Ratio: 10:1 to 100:1 depending on drive system. Variable frequency drives provide superior turndown compared to mechanical speed variation.
• Chemical Compatibility: Hose material selection critical - EPDM for chlorine solutions, Viton for aggressive chemicals, natural rubber for neutral pH applications. Temperature limits typically 32-140°F for most elastomers.
• Power Requirements: 0.5-10 HP motors typical for municipal applications. Higher pressures and flows require proportionally more power due to hose compression energy losses.
• Pulsation: Inherent to peristaltic action but minimized with multiple rollers (6-12 typical) and pulsation dampeners when required.

• What chemical feed accuracy is required and can peristaltic pumps meet process control requirements? Municipal disinfection typically requires ±2-5% accuracy, while polymer feed may accept ±5-10%. Peristaltic pumps provide excellent accuracy but require proper calibration and hose replacement scheduling.
• Can the system handle inherent flow pulsation or are dampeners required? Pulsation amplitude typically 10-30% of average flow. Critical for pH control or precise dosing applications. Dampeners add $2,000-5,000 cost but may be essential for process stability.
• What is the expected hose replacement frequency and lifecycle cost impact? Hose costs $200-2,000 depending on size and material. Replacement every 6-18 months typical in continuous service. Compare to diaphragm pump valve replacement costs.
• Does the installation require suction lift capability exceeding 20 feet? Most peristaltic pumps handle 25-foot lift, but performance degrades significantly above 20 feet. Consider flooded suction or booster pumps for challenging installations.

• Division 40 - Process Integration: Section 40 05 23 - Chemical Feed Pumps
• Primary application for municipal chemical dosing systems including chlorine, polymer, and pH adjustment applications

• Material/Equipment Verification: Verify hose material compatibility with specific chemicals and concentrations, confirm pump head materials (316SS standard for municipal applications), check calibration certificates and flow accuracy specifications
• Installation Requirements: Level mounting surface required for consistent flow, adequate clearance for hose replacement (typically 12-18 inches), proper suction lift limitations (typically 6-8 feet maximum)
• Field Challenges: Hose routing to avoid kinks and sharp bends, priming procedures for self-priming limitations, calibration verification during startup
• Coordination Issues: Chemical storage tank level controls integration, SCADA signal compatibility (4-20mA standard)
• Lead times typically 6-12 weeks for standard models

• Watson-Marlow - Qdos series (municipal chemical feed, 0.001-26 GPH typical)
• Grundfos - DDA/DDC series (chlorine/polymer feed, 0.3-95 GPH range)
• Verder - Dura series (abrasive slurries, lime slaking applications)
• Cole-Parmer - Masterflex L/S series (lab/pilot applications, some small municipal chemical feed)
• All maintain strong municipal references with proven installations in water/wastewater treatment facilities

• Progressive Cavity Pumps - Better for higher flows (>50 GPH), similar chemical compatibility, 15-25% higher cost but longer service intervals.
• Diaphragm Metering Pumps - More precise control, higher pressures, preferred for critical chemical feed, 25-40% higher initial cost.
• Gear Pumps - Lower cost option for non-critical applications, limited chemical compatibility, 30-50% cost savings but higher maintenance requirements.

Establish service agreements with local manufacturer reps for hose replacement - typical hose life ranges 6-18 months depending on chemical and duty cycle. Stock spare hoses on-site as emergency replacements. Consider oversizing pumps 20-30% for chemical feed applications to account for hose wear degradation. Watson-Marlow and Grundfos offer excellent technical support for troubleshooting flow inconsistencies. Calibrate monthly using graduated cylinders rather than relying solely on pump settings.