Twin Pump Pressure Washer System: Pressure Control & Flow Sharing Using Optiflow Software
This project involved the design and build of a variable speed drive control system for a twin pump pressure washer installation. Using Invertek Optidrive ECO inverters with built-in Optiflow software, the system automatically controls pump speed in response to water pressure demand, allowing the two pumps to operate together efficiently while maintaining a constant system pressure.
Project Overview
Motor Control Warehouse was asked to design and build a control system for a twin pump pressure washer installation supplying two individual pressure hoses for a range of washing applications.
The system was designed to maintain a constant water pressure while ensuring that the two pump motors operate efficiently across varying levels of demand.
To achieve this, the engineers at Motor Control Warehouse used two Invertek Optidrive ECO variable speed drives with built-in Optiflow software. The drives continuously adjust the speed of the pump motors in response to pressure feedback, allowing the pumps to operate in a coordinated cascade and flow-sharing configuration.
The Challenge
The pressure washer system needed to supply two separate pressure hoses used for a variety of washing applications. Water demand would therefore vary depending on how many pressure washers were being used and the level of flow required.
A conventional fixed-speed pump arrangement would require the pumps to operate at a constant speed regardless of demand, potentially resulting in unnecessary energy consumption and inefficient operation.
Motor Control Warehouse needed to develop a system that could:
- Maintain a consistent water pressure
- Automatically respond to changing demand
- Allow the two pumps to operate efficiently together
- Prevent the pumps from operating below their minimum safe speed
- Reduce unnecessary energy consumption when the pressure washers were not in use
- Provide the client with clear system and energy information
- Allow the system to be operated in both automatic and manual modes
The Solution
Motor Control Warehouse designed and built a fully automated twin pump variable speed drive control system using two Invertek Optidrive ECO low-harmonic fan and pump drives.
Each inverter uses Invertek's built-in Optiflow software to control the speed of its associated pump motor in response to the system pressure. A 4–20mA pressure sensor provides continuous feedback to the control system, allowing the drives to automatically adjust pump speed to maintain the required pressure.
The two Optidrive ECO inverters operate in a cascade and flow-sharing configuration, working together to match pump output to the system demand. This allows the pumps to operate at their optimum flow level rather than simply running continuously at full speed.
When demand increases, the system can increase pump speed and bring additional pumping capacity into operation. When demand reduces, the drives reduce pump speed accordingly.
When the pressure washers are not being used, the system can automatically place the inverters into standby mode after an adjustable period. This disables the inverter output stage, preventing unnecessary motor heating and further reducing energy consumption.
Key Features
- Twin pump variable speed drive control system
- Two Invertek Optidrive ECO AC drives
- Built-in Optiflow pressure control software
- Automatic cascade and flow-sharing operation
- 4–20mA pressure sensor feedback
- Constant water pressure control
- Automatic standby mode when demand is absent
- Pump dry-run protection using a tank-mounted float switch
- Programmable minimum pump operating speed
- Front panel-mounted remote Optidrive OLED display
- Flow and energy information available to the end user
- Hand and automatic operating modes
- Low-harmonic drive technology
- Designed and built by Motor Control Warehouse
The Technology
The Invertek Optidrive ECO drives were selected specifically for their suitability for pump applications and their integrated energy-saving features.
The drives incorporate low-harmonic technology to minimise harmonic content on the mains supply, while the built-in Optiflow software provides dedicated pump control functionality without the need for additional external control equipment.
Pressure feedback is provided by a 4–20mA pressure sensor, allowing the drives to continuously monitor system pressure and adjust pump speed accordingly.
The system also incorporates dry-run protection through a tank-mounted float switch. A programmed minimum speed ensures that the pumps do not operate below their required minimum operating speed.
A remote Optidrive OLED display mounted on the front of the control panel provides the operator with accessible system information, including flow and energy data.
Outcome
The completed system provides the client with automatic and efficient control of the twin pressure washer pumps, maintaining the required water pressure while adapting pump output to the actual demand of the system.
By controlling pump speed rather than simply running the motors at full speed, the system reduces unnecessary energy consumption and allows the pumps to operate closer to their optimum flow conditions.
The automatic standby function provides further energy savings when the pressure washers are not in use, while the integrated protection and monitoring functions help ensure reliable operation of the pumping system.
The result is a more efficient and flexible pressure washer installation, with automatic pressure control, coordinated pump operation and improved visibility of system performance.