Document 6RZYe5q4nVnkjMeqgVMm8zJ03

298 Controls and Instruments Field Control Division H. D. Conkey & Company, Mendota, 111. Field Barometric Draft Controls Field M+MG2: A Three-Fuel Control, in Sizes 10 in. through 32 in., for Oil, Oil-Gas, Gas, and Coal Fired Furnaces and Boilers. The M+MG2 will serve gas, oil or coal with equal efficiency, and requires only minor, in-the-field changes to adjust from one fuel to another. A plant might con vert from coal, to oil, to gas, then to oil-gas, without obsoleting this control. With coal it serves as a combi nation barometric draft control and check damper. With oil it serves as a single-acting barometric control. With gas it becomes a double-acting control, opening inward to regulate up-drafts, opening outward to re lieve down-drafts. Where gas-oil is used interchange ably, the control change takes less than a minute. .. The Field M -fMG2 is a specialized, precisionmade, three-fuel control. Because it is a control of extreme sensitivity, it is, of necessity, a control of extreme structural strength. For example, accuracy is increased when the clearance between a ring and gate is held to a minimum. To permit this, in the M+MG2, without risk of binding, Field developed a die-formed, heavy gage ring. Its deflection strength exceeds many fold the normal requirements of shipping, installation or use. The gate is also very heavy--39 pounds for a 32 inch control. Such weight obviously provides ex treme rigidity. Heavy weight is also, paradoxically* a requirement of the virtually friction-free gate mount ing that gives the M+MG2 its extreme sensitivity. Only a heavy gate could be so delicately balanced. The same weight factor also prevents the spurious responses to which so sensitive a gate might normally be subject. The M+MG2 gate is mounted on a long, thin, stainless steel knife edge, which in turn rests on self aligning bearings. The bearings are self-cleaning. Soot or dirt cannot accumulate to cause binding or friction. They are also self-leveling--assuring that the knife edge is always in contact across the full width of the bearing, for an even distribution of weight. When the gate moves, only the sharp corner of the knife edge rests on the bearings--an area of contact so minute that friction is virtually non-existant. The result is extreme and instantaneous sensitivity to draft change. The gate is deeply recessed in the ring, to direct the flow of air over the gate and avoid response to random, variable air conditions outside the control. The M+MG2 permits an unusually wide range of draft settings. The 18 in. control* for example, will maintain a draft setting as low as 0.002 in. The same control will maintain a draft as high as 0.3 in., a re quirement where there is a very high draft loss through the appliance. Compensation for differences between horizontal and vertical installation is fully provided, by the simplest means available on any Field control. Where a safety switch must be specified, to meet gas code requirements, attachment is easily, effectively, and compactly made. Compactness is a characteristic of the M+MG2. There are no protruding parts. Even the stainless steel bead chain is short, holding setting weights neatly against the side of the control. Unless otherwise specified the M+MG2 control is shipped as a singleacting control, with patterned collar. For gas, the installer will set control for double-action. If solid fuel is involved, order the M+MG2 Barochek. If control is to be shipped less collar, so specify: Bf + MC2 Doable Acting for Gas, opens inward to regulate up drafts, and opens - outward to relieve internal pressures Controls and Instruments Field Control Division 299 PHYSICAL DATA Noataal Recon. Pipe Sim $bp|.WL Vol(Ca.Ft) Centre) Size SqTlii7 Ota. Circcm. J Comp. LC. Coop. LC. 10 715 9 & 10 28% to 31* 10 4% 5 4* 11 3* 1* 4* i 3* 1 14* 9* 0 7*0 .76 .49 12 1)3 11112 34ft to 3714 12 5* 6 5 13* 4* 1* 4* 1 3* * 16* 11* 8*0 122 .70 ft14 154 13(14 4014 to 44 14 7* 7 5* 15* 5* 2* 5* 1 3* * 19* 170 110 3.12 1.02 16 201 15(16 47 to 50)4 t6 fei 6 6* IT* 6* 2* 5* 1* 4 22 280 17*0 3.1 1.41 It 255 17(16 S3Vb to 56* 18 6* 9 1* 19* 6* 2* 7* 1* 5* 1ft 24ft 340 22*0 in 109 26 314 19 to 21 SSttto Is 20 6* 10 8* 22 7* 1 7* 1* 6* 1* 27* 42* 0 28*0 5.65 190 ft24 452 22 to 25 69 to 76* 24 12* 12 10* 26 9* 3* 6* 2 6* 1* 32* 850 440 7.18 4J5 28 616 26 to 30 6114 to 94* 26 11* 14 30* IW4 4* 11* 2 6* 33* 950 690 7J0 m 32 604 31 to 34 97* to 107 32 15* 16 * 35 12* 4* 12* 2 6* * 43* 1250 890 1220 1120 . *No Petals 0a Theta CnUrT SWITCHES: A draft hood provides relief for down draft pressures,- but gives no visual sign of spillage. The double-acting M+MG2 gate opens outward to relieve such pressures, and by its position signals any spillage. In addition, the M+MG2 can be equipped with an automatic switch where the engineer finds conditions which could create frequent and pro longed down drafts. A time delay switch is usually recommended for an atmospheric burner; a thermal switch for a power burner. These switches provide an obvious means to measure the extent of a down draft problem so that an engineer can judge if and when some remedial action is indi cated. BEST LOCATIONS FOR GAS BEST LOCATIONS FOR OIL OR SOLID FUELS S\ FIELD TYPE M: For automatic heating equipment, designed to as sure finer performance, greater fuel economy, through highly accurate control of drafts. Available in sizes from 6 in. through 9 in. for pipe di ameters of 5 in. through 10 in. Fea tures "Rocking Chair" gate action, off-center gate mounting, sidewings, extended housing. Widely used in the - heating industry. FIELD TYPE RC: Calibrated draft control in sizes 6 in. through 9 in. for. 5 in. through 10 in. flues. Features extreme capacity, and re versible wing flap on gate for more precise adaption to either vertical, horizontal or sloping flues. Frictionfree gate mounting, single strap at taching, easily leveled on a sloping flue. FIELD MG1: Double-acting con trol for lower-input gas-fired fur naces and boilers; widely used in conversion burner installations. Opens outward to relieve downdrafts ; opens inward to regulate up drafts. Sizes 7, 8, and 9 in. for 6 through 9 in. flues.