Correct Aggregate Batcher Gate Operation for Concrete Plants

This is one in a series of articles designed to familiarize you with your concrete batch plant. Aggregate batcher discharge gate(s) are operated by a pneumatic cylinder. The cylinder receives air from a double acting solenoid valve that operates from an electrical signal from the batch control. To operate a double acting (inching) solenoid valve, two signals are required; one open and one closed. Both signals need to be momentary. Flow controls are installed on the solenoid valve or cylinder that regulates the air flow to the cylinder. The flow controls are installed allowing the operator to regulate the speed at which the cylinders move to allow for precise control of the gates; critical for accurate and efficient concrete batching.

During normal operation of the concrete plant, the batch control will control the operation of the gates and the discharge rates. The concrete batch control needs to be programmed properly to operate the gate efficiently. Below are some settings that may affect the operation of the gate. Note: These settings may be labeled differently depending on the manufacturer of the control.

Flow Rate (Minimum and Maximum) – Most batch controls try to obtain a flow rate when discharging; they will typically try to stay in a range and work off of a minimum and maximum setting. The settings for this need to be determined for each concrete plant individually.

Initial Open – The initial open setting is used to get the gate opened at the start of discharge. Typically the initial open setting should get the gate 1/4 – 1/3 of the way open with the first pulse or to get a good flow rate started.

Open and Close Pulse – After the discharge gate has been opened with the initial open pulse, the open and close pulse takes over for the remainder of discharge. If the batch control determines that the flow rate needs to be adjusted a pulse will be sent to open or close the gate depending on if the discharge rate needs to increase or decrease. Each open or close pulse should move the cylinder 1/8 of its overall travel.

Our thanks to CON-E-CO and others for making this information available so concrete producers can operate their concrete plants efficiently and profitably with minimal challenges.