In an agitator used in chemical mixing, constant speed is required for accurate production. A new air motor and speed sensor system from Deprag helped to remove any undesirable speed changes.
However, speed regulation is often an issue, so Deprag Schulz GmbH, Amberg, Germany, developed an innovative speed regulator for their air motors. Combined with smart sensor technology, the air motor will always hold the desired preset speed.
According to product manager Dagmar Dbbelde, “It is characteristic for an air motor to operate under many changing loads. When operated without load, the motor runs at its rated noload speed. If the load increases, the motor’s speed decreases. So an air motor can be operated at approximately 15% to 100% of its nominal speed, depending on its load requirement.”
This can cause problems. For example, in an agitator in a chemical mixer, a constant speed is required for accurate production. If the viscosity of the mixture or its volume changes, an undesirable speed change occurs. When confronted with this problem from a customer, Deprag went to work on a new speed regulator.
Simple and reliable operation
The controlledspeed air motor for the agitator consists of three components. The motor is based on Deprag’s stainlesssteel Advanced Line, which meets oil-free operation needed in clean room environments for hygiene and safety. When equipped with the sensor and special valve, the motor offers innovative speed control. Additionally, the regulator electronics allow installation into a user’s control box. Finally, an operator friendly LCD is used for simple and uncomplicated speed value selection.
The new speed regulator relies on a non-contacting speed sensor integrated directly into the air motor, between the vane air motor and gearing. The sensor monitors the motor’s actual operating speed, which is transferred as a digital signal to the regulator. The operator uses an LCD interface on the agitator controller to enter the desired nominal speed, and the regulator compares the two values. Variation between the actual speed and nominal speed causes a proportional valve to be actuated to increase or decrease air flow to the motor and, therefore, its speed. The result: The air motor operates consistently within the required speed range.
The speed regulator is used with the stainless steel 67-028R air motor. The nominal speed of this 1200-W motor is 1250 rpm, the no-load speed is 2500 rpm, and the nominal torque is 9.2 Nm — all based on an operating pressure of 6 bar. The air motor operates the agitator for mixing fluids ranging in viscosity from 1 to 300 mPa. It maintains its speed within the required tolerance independent of viscosity or volume fluctuations of the mixture in the receptacle.
Suitable for many applications
