Two Stage Digital Control Valves

Typical Control Systems consist of three primary pieces of equipment: Flowmeter, Preset Batch Controller, and two-stage digital shut-off valve. The meter is the primary flow measuring device. The preset batch controller is used to determine the volume of liquid to be controlled by the valve at predetermined batch quantity setting. The sequential logic of the batch controlling mechanism control the solenoid pilots of the control valve.

The control valve is designed to close in two dist inct stages. As the preset counter reaches the pre-defined quantity, it closes the main valve & the first stage closure reduces the flow rate through the valve to minimum flow rate for safe stop at preset quantity.

Approximately 10 to 20 percent of the rated capacity of the meter. The preset trips the sequencing logic control output and the valve closes.

For instance, you may want one hundred Liters in a particular batch. You may also want a valve to close and slow down flow 25 Liters before the end. Your preset is 100, your Pre-warn is 25. When the start is activated, the valves energize simultaneously to start flow. When the totalizer reaches 75, the pre-warn solenoid valve drops out. When the totalizer reaches 100 the preset valve drops out. The preset values can be viewed or changed via the menu (when stopped).

Vermont make Two-Stage Valve is normally closed and designed for precise, accurate control and shut-off of batching operation. The valve controls a predetermined amount of product to guarantee smooth, positive shut-off.