Innovative speed control pump solution for injection moulding

The usage of speed controlled pump solutions can significantly impact energy savings in injection moulding. In addition to energy savings, it also reduces the Total Cost of Ownership (TCO). Admittedly, these were also the key drives behind an innovative solution – the Speed Controlled Pump System (SCP System) – to be launched for an application for hydraulic control, where the need for energy efficiency is growing globally and the cost pressures have been high as well.

The conventional hydraulic system for an industrial machine consists of a variable displacement pump and an induction motor which is directly connected to the power grid. In this typical system, the motor runs at a constant speed, normally at 1500 to 1800 rpm, and uses the internal mechanism to change the output flow of the pump.  In this system, there are substantial energy losses in the induction motor and in the adjustment mechanism of the pump - particularly when the system is working under partial load or in standby mode.

For industrial machine builders, increasing energy prices and the need for environmental awareness are strong drivers prompting end users to request machines that are high on performance and low on energy consumption in addition to reduced TCO and improved environmental conditions such as sound emission levels.

Energy Savings with the SCP System
The SCP system consists of integrated building block products including a dual displacement Radial Piston Pump (RKP), the Maximum Dynamic Brushless Servo Motor and the Modular Multi-Axis Programmable Motion Control Servo Drive (MSD). The key functionality it offers is the ability for users to change the speed of the motor and pump and enable control of fluid flow.

The system is capable of significantly optimizing energy efficiency on machines. The energy efficiency of a machine with the SCP system is higher - especially when the machine works under partial load. With a medium load, the efficiency is 20-30 percent higher compared to a traditional system. When a machine is running without load or in a standby mode, up to 90% lesser energy is consumed. Under full load conditions, the performance in comparison to the variable displacement system is nearly identical.

An innovative flexible system
The concept behind the system is not new but Moog engineers were able to improvise on this technology to enable better performance.  The primary building blocks are all designed and manufactured by Moog, allowing engineers to optimize their performance in an integrated system. Another important innovation in the system is the dual displacement pump design, which allows the pump to operate between two displacements. This functionality is especially important if the application has a load-holding phase where the machine needs low flow, but high pressure. With a dual displacement pump design, it is possible to switch to lower displacement, which requires reduced torque. As a result, the motor size required for the system can be reduced and this leads to energy savings owing to the more efficient operation of the motor.

In addition to energy savings, the SCP system offers the advantages of a compact design and easier systems integration. The package is more compact as the size of a synchronous motor is much smaller than the corresponding size of the induction motor.  Integration is simpler when compared to traditional systems where the fieldbus communication is interfaced through the pump control as it is linked to the automation system. In the SCP system, the fieldbus is through the servo drive electronics - similar to the configuration in an electromechanical axis - thereby making it easier to integrate.

The SCP can also be designed with a submerged installation of the motor and pump inLunar Flyknit Chukka