SHORT ANSWER
Select from the operating point, then verify the liquid and pressure limits.
State the required flow and total dynamic head, then choose a CDLF model whose duty point lies in the recommended region of its curve. Verify liquid temperature, material compatibility, maximum system pressure, suction conditions, motor supply and seal arrangement. A representative CDLF family may cover approximately 2–80 m³/h, pressures up to about 2.4 MPa and liquid temperatures from −20 to 150°C, but the exact model and construction govern.
Where a CDLF pump fits best
The vertical in-line multistage arrangement places several impellers in series so each stage adds head. Stamped stainless-steel hydraulic components provide smooth flow passages and a compact vertical installation. Common duties include building and industrial pressure boosting, reverse-osmosis pretreatment, filtration skids, washing systems, cooling-water circulation, boiler feed and clean process-liquid transfer.
The term “stainless” does not mean suitable for every chemical. Chloride level, pH, temperature and cleaning chemicals all affect grade and seal selection.
Calculate flow and total dynamic head
Flow comes from process demand: simultaneous users, production rate, filter throughput, boiler consumption or circulation requirement. Head must include static elevation, required terminal pressure, vessel pressure and all pipe, valve, filter and equipment losses at the design flow.
Do not select by maximum head or motor power alone. Plot the operating point on the performance curve and avoid operation at the extreme left or right unless the manufacturer has reviewed it. Check minimum continuous flow, efficiency, motor power, NPSH required and the effect of speed control.
| Check | Question to answer |
|---|---|
| Flow range | What are minimum, normal and maximum simultaneous demands? |
| Total head | What pressure remains after static lift and every system loss? |
| Inlet condition | Is suction flooded, and is NPSH available adequate at the hottest condition? |
| System pressure | What is the highest casing pressure at shutoff and maximum inlet pressure? |
| Control | Fixed speed, variable speed, pressure transducer or multi-pump staging? |
Keep solids, gas and cavitation out of the pump
Standard CDLF pumps are intended for clean, non-abrasive liquid without significant fibers or particles. Abrasives wear the close-clearance stages and mechanical seal. Entrained gas can destabilize performance and interrupt lubrication. If the source tank can empty, add level or dry-run protection.
High liquid temperature lowers available suction margin and changes elastomer and seal requirements. For boiler feed, hot-water circulation or pressurized suction, provide the full temperature and inlet-pressure range—not only the discharge target.
Design the system around the whole operating range
For constant-pressure boosting, a variable-frequency drive and pressure sensor can reduce throttling losses and maintain stable delivery. Multiple pumps may be staged for variable demand and redundancy. Include a check valve, isolation, pressure protection and adequate minimum flow as required by the system.
Pipe alignment matters. Support suction and discharge piping independently, avoid strain on the in-line connections, vent the casing before startup and confirm rotation. Never start the pump dry.
Frequently asked questions
What is CDLF mainly used for?
Clean-liquid boosting and circulation where compact high head is required, including water treatment, filtration, washing and boiler-related systems.
Can it pump dirty water?
Not as a standard selection. Abrasive particles and fibers can damage the stages and seal.
How many stages do I need?
Choose stage count from the curve at required flow and total head, then verify pressure, power, NPSH and operating limits.
Send us the CDLF operating point.
Include flow range, total dynamic head, inlet pressure, liquid and temperature, site power, control method and any material restriction.
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