OPERATION & SAFETY CONTROLS


FALCO oxidizers have three programmable temperature controllers that respond to temperature sensors located before (T1), inside (T3), and after (T2) the catalyst. The controllers start, run, and shutdown the oxidizer based on catalyst temperature. High and low alarms shut the system down (blower and heaters) if temperatures exceed preset limits.

A Vapor Control Valve (VCV), installed on the vacuum side of the vapor extraction blower, includes a valve body, valve disc, two valve seats, and a small gear motor. The motor progressively opens and closes the valve in response to input from the three controllers. A solenoid valve provides rapid introduction of dilution air, regardless of valve position.

The VCV regulates input concentrations and provides smooth start up. The VCV simultaneously regulates dilution air and source vapors and accommodates increases and decreases in concentrations. The valve returns to its closed position each time FALCO power is cycled.

After controller set points are adjusted, and the power switch is cycled, startup begins automatically. The VCV first returns to its closed position. Once closed, a switch on the VCV allows the vapor extraction blower to start. A pressure switch senses flow to the oxidizer and allows the electric heaters to preheat the catalyst bed to its reactive temperature. Once up to a preset temperature, the VCV is enabled and vapor introduction begins. The rate of concentration increase, and resulting temperature rise, is controlled by rate alarms on the T2 and T3 controllers. The VCV automatically responds to changes in vapor concentrations by adjusting valve position.

The vapor extraction blower interlocks with the FALCO control panel. Low temperature alarms shut the blower down if catalyst inlet temperature is not maintained. Redundant high temperature alarms shut the blower down if temperatures exceed preset limits. Alarms latch and must be cleared by the operator. A pressure switch interrupts the heater circuit if flow to the oxidizer stops.

In the event of a power failure, the VCV returns to its closed position. When power returns, FALCO automatically executes its start up sequence. Cycled operation is achieved by interlocking control power with a timer. Automatic switching of vapor sources is easily accommodated.

A heat exchanger bypass valve provides manual regulation of heat recovery efficiency. Vapor input concentration is regulated by the VCV in response to heat recovery. High heat recovery results in low input concentrations. With low heat recovery, the VCV maintains high input concentrations. This adjustment allows the operator to easily tune the FALCO to specific site conditions