CDLF-ZN Vertical Multistage VFD Constant Pressure Pump

TheCDLF-ZN vertical multistage VFD constant pressure pump, also known as the single-pump variable frequency constant pressure booster unit, is an integrated water supply system combining a stainless steel vertical multistage centrifugal pump, an independent variable frequency drive (VFD) control system, and pressure-stabilizing accessories. Operating as a smart variable frequency pump, it utilizes single-pump one-to-one control with PID closed-loop speed regulation to maintain consistent pipeline pressure. Designed for low-flow, medium-to-high pressure applications, this vfd pump unit serves as an economical pressure-boosting solution for small buildings, industrial equipment matching, and circulating water systems.

Core Components

• Vertical Multistage Centrifugal Pump (CDL/CDLF): Features a vertical series-connected multistage impeller structure with 304 or 316 stainless steel wetted components for hygienic, rust-free operation. The multistage impellers boost pressure stage by stage to achieve high head, while in-line horizontal ports allow direct pipeline integration.

• Dedicated Single-Pump VFD Control System: Features an integrated drive or VFD control cabinet with built-in PID constant pressure regulation. Enables smooth soft starts without current shocks to eliminate electrical spikes on water pressure booster pumps.

• Pressure Collection Assembly: Employs a high-precision 4–20 mA pressure sensor to measure outlet network pressure in real time, sending feedback to the vfd pump controller for closed-loop adjustment.

• Pressure Stabilizing & Buffer Unit (Pressure Tank): Includes a bladder-type pressure tank to store pressure and buffer fluctuations, maintaining stable pipeline pressure during low-flow periods while reducing frequent pump starts and mechanical seal wear.

• Pipeline, Valves & Integrated Base: Assembled on a skid-mounted vibration-damping base with a stainless steel main pipe, check valve, gate valve, and pressure gauge, creating a plug-and-play variable frequency pump system ready for immediate piping connection.

Working Principle

• Pressure Detection: The pressure sensor collects the actual water pressure signal of the pipe network in real time and transmits it to the VFD.

• Smart Calculation: The controller compares the set constant pressure value with the measured pressure, and outputs frequency adjustment commands through PID calculation.

• Increased Water Consumption (Low Pressure): The VFD increases frequency, the motor speeds up, and the water pump discharge flow and head are simultaneously elevated.

• Decreased Water Consumption (High Pressure): The VFD decreases frequency and the motor operates at low speed. During trace water consumption at night, pressure is maintained by the pressure tank, and the water pump starts and stops intermittently.

• System Protection & Automation: In the event of water shortage, overload, overpressure, or electrical leakage, the system automatically shuts down and alarms, achieving fully unattended automatic operation throughout the entire process.

Structure