| SPECIFICATION | |
|---|---|
| Operating Element | Slack leather diaphragm. |
| Action | Single speed floating control with adjustable "dead" zone. |
| Connection | 1/2" B.S.P.T. male. fitted with pulsation damping 1.2mm dia. orifice. |
| Setting Range | 0 to 2.5 mbar (0 to 1" W.G.) vacuum. Ranges of 0 to 1.25 mbar and 0 to 10 mbar (0 to 1/2" W.G. and 0 to 4" W.G.) are obtainable with alternative springs also provided. |
| Mounting | Wall mounting by projecting plates on either side of case which have slotted holes to take 6mm dia. holes(1/4") screws. |
| Switch | S.P.D.T. mercury tube. (MSM 438) |
| Electrical Rating | 6 amp. |
| Maximum Voltage | 250 Volts AC. |
| Mains Connection | Alternative entry grommets on either side and underside of case 12mm (1/2") dia. bore. Terminal block inside case. |
| Weight | 3.3Kg |
The Drayton SL2 Furnace Draught Controller has been developed to meet the requirements of boiler, stoker and oil bunker manufactures for a simple, electrically operated draught control.
The measuring element consists of slack leather diaphragm unit which operates a 3-way mercury-tube switch through a adjustable linkage to reverse the switching of a damper motor. Single speed floating control is thus achieved. Any deviation from the set pressure causes the mercury switch to operate the damper motor and move it in the appropriate direction until the set point is regained. The control system is then in equilibrium and the damper motor at rest. The repeatability of this instrument is of the order of 1% of the setting range. A setting scale is incorporated but the instrument is none-indicating.
The Drayton RQR or RQ53 motors used with the draught controller have final shaft speeds of 4 m.p.r. and 3.9 m.p.r. respectively, the internal limit switches being set to meet the desired requirements.
