Specification:
- The gas feeder shall automatically regulate chlorine gas feed rates in response to flow and/or residual input signals. The panel shall contain an automatic gas control valve with an integral controller, gas flowmeter, vacuum gauge, and optional high and low vacuum switches. The wall panel shall have a maximum capacity of chlorine gas feed rates in response to flow and residual input signals. The wall panel shall have a maximum capacity of 3000 lb/day/60 kg/h and operate under sonic flow.
- The flowmeter with dual scale (English/metric) shall indicate the gas flow and shall have a maximum indicated capacity of _______ lb/day. The entire panel shall operate under vacuum from the gas inlet connection to the gas outlet connection.
- The Gas Flow Control Valve shall be a stepping motor operated with the motor and electronic components mounted in a NEMA 4X enclosure. The valve shall be integrated with a microprocessor-based controller designed to control chemical feed. The valve shall be field configurable for flow proportioning, residual, compound loop or feed-forward control. The compound loop control feature shall have the capability of automatic variable lag time adjustment. All setup, tuning and control adjustment shall be achieved from the pushbutton panel.
- Standard features shall include: built-in multiplier for feedforward control: automatic transfer from compound loop control when either the residual or flow signal is lost; bump-less transfer between manual and automatic control, digital vacuum fluorescent display; alarm indication; user-configurable alarm contacts; control switch inputs; and a 4-20 mAdc flow transmitter output signal.
- The valve shall be capable of a unique 11 point valve plug characterization feature that matches the valve plug characteristic to the gas flow meter. This shall insure a true gas flow retransmission signal to remote monitoring instruments such as a recorder or SCADA system without the need for limited range auxiliary differential pressure metering devices. The valve shall operate under sonic gas flow conditions without the requirement for a differential pressure regulator to maintain a constant flow rate with varying vacuum levels.
- The valve shall be able to accept three (3) either 4-20 mAdc or 1-5 Vdc inputs. Inputs shall be field selectable, two (2) for flow transmitter and/or residual analyzer and one (1) for remote setpoint. There shall be two (2) contact inputs one shall be for vacuum switch alarm and the other for a remote standby switch.
- The display shall be a 2-line, 16 character vacuum fluorescent display. The display shall display operational parameters as well as alarm conditions. The valve shall be powered by 100-250 Vac, 47-66 Hz and shall be auto-ranging. The valve shall be equipped with a manual control knob (multi-turn) available to position the valve plug when dosage control is in “off” position or if power fails.
- The valve shall be able to feed chlorine, sulfur dioxide, ammonia or carbon dioxide gases. The maximum feed rate shall match the flowmeter capacity indicated above.
- The optional vacuum switches shall be wired to the automatic control valve and have auxiliary contacts available for remote status indication. The vacuum switches shall monitor the vacuum levels from the vacuum source and the vacuum level between the panel and the vacuum regulator.
- The panel shall be of rigid polyethylene. All components shall be pre-wired and pre-piped using materials suitable for gas service.
- The vacuum inlet and vacuum outlet shall be 5/8 inch tubing for 500 lb/day and below, and 1-inch NPT for above 500 lb/day.
- The wall panel shall be DE NORA WATER TECHNOLOGIES, INC. 3000WP.
