(Continued from Pag* C 2) when the fan is not in use. Without a shutter, fan openings will act as an inlet and hence disrupt the ven tilation system air flow and static pressure. Another common fan accessory is a guard which is essential for the safety of people and animals around the fan. A guard also pre vents objects from damaging tv entangling the fan. Guards do not disrupt air flow nearly as much as shutters. A guard may decrease air flow and efficiency by less than 5 percent Ring guards, with a con centric circular wire grill, disrupt air flow less than interwoven wire mesh guards. Fans with well designed hous ing and inflow and discharge cones have improved efficiency. Well designed fan housings have close tolerance between the fan blade tip and the housing surrounding the blades. This discourages back flow of air through the fan and hence improves air flow efficiency. Streamlined air flow into the fan Rugged Enough For lime, Precise Enough For Fertilizer. You know how tough it is to spread wet lime. And fertilizer is too expensive to waste. Our new 56i spreader does both jobs with ease. Plus, it has no equal when it comes to spreading “sloppy” material. Stoltzfus Spreaders have been known as unique, “top-of-the-line” ag spreaders since 1947. • Press-wheel ground drive • Walking-beam suspension • Corrosion-proof steel hopper 1 800 843 8731 • UHMW plastic floor • Lime: 3 tons / acre max. Fertilizer: 125 lbs. / acre min. blades is desirable. Inflow cones provide a short duct of streamlined air, which improves fan operating efficiency. Discharge cones pro vide a similar function but are less effective in improving fan effi ciency than inlet side cones. Table 1 shows rated fan perfor mance data essential in selecting fans for a well designed ventilation system, comparing a bare fan and the same fan with guard and shut ters in place. When these data are graphed, the curves show the char acteristics of fan air delivery at various operating static pressures (Figure 1). Note that the decrease in air flow from fan accessories is important to account for in system design. Design air flow will not be met if accessories are ignored. Consider a layer house where a set of 10 stage-one 36-inch fans were installed with external shutters, yet the decrease in air flow these shut ters caused was not accounted for in specifying the type and number of fans. The building was 20 per cent underventilated when the The One Spreader Morgan Way, P.O. Box 527, Morgantown, PA 19543 Farmers are still using Stoltzfus Spreaders they’ve had 20 years or more. That means your investment in a versatile Stoltzfus Spreader will add up to a very smart buy indeed. Call or write today for a free brochure and the name of the dealer nearest you. STOLTZFUS stage-one fans were operating at full capacity. The recommendation was to position the shutters on the inside of the fans to improve perfor mance. In practice, these continu ously operating, stage-one fans would never be turned off. so there would be no need for shutters. The shutters could be removed for even better air flow performance. What kind of accessories will an agricultural fan need? A fan needs a guard for safety of animals and workers and to protect the fan from damage. Shutters are necessary on most fans and are best installed on the inside of the fan for less air flow disruption. Well designed fan housing con struction will improve efficiency and is found on most engineered fans. For improved fan perfor mance, inlet cones are more effec tive than discharge cones. The minimum accessories are a guard and shutters on a well designed fan. It is important to remember that ventilation is a system. The fan is only one component which per forms an important function of creating the static pressure differ ence which drives the ventilation air exchange. Inlet and air distribution compo nents have a tremendous effect on lancaatar Fuming, Saturday, March 16,1996-C3 the success of a ventilation system. Fan and equipment selection should use data from rated fans which have been tested in condi tions under which they will be operated and with the necessary accessories such as guards and shutters. In this way, you can be assured of obtaining your system’s ventilation air exchange rate. 25000 20000 15000 I « 10000 < 5000 0 0.05 0.1 0.15 0 2 025 0.3 Figure 1. Plot of multi-rating table data (Table 1) for a 48-inch fan with no accessories and the same fan with shutters installed. Note the decrease in performance which MUST BE ACCOUNTED FOR when shutters are used. More infomiation is available on this subject: Fan Selection and Case Study, GBS. This and other fact sheets arc available from Agricultural and Biological Engineering Extension, 246 Agricultural Engineering Bldg., Penn State University, Uni versity Park, PA 16802 (phone: (814) 865-7685). • cfm 48-inch fan □ cfm 48-inch fan with guard & shutters * •. ° 0 □ Static Pressure (inches water) KEN CLUGSTON (717)665-6775 CRAFT-BILT CONSTRUCTION INC. FARM-HOME BUILDING 1242 Breneman Road MANHEIM, PA 17545 PH: (717) 665-4372 BUILDING & REMODELING FOR DAIRY RESIDENTIAL SWINE POLE BUILDINGS 3 BEEF STORAGE SOYBEAN ROASTING ON YOUR FARM PUT “VALUE” IN YOUR GRAIN AND NEVER LEAVE THE FARM • We Roast Your Beans • Avoid Trucking Expenses • Avoid Docking tritionai Vaiue: • Increased Palatability • Uniform Golden Appearance »Cooling for Immediate Storage Available ONLY WE CAN GIVE YOU “FLAME-KISSED" QUALITY '• Roasting Otet pnit AvsiMnb)* Custom Wor* ' ‘ OHlfnit^aUns * «oe, Uti«rK}ft, PA 1-800*5*4004 (717)865-6611 Horst Grain Roasting 3040 Penns Grove Rd David N. Graff Lincoln University, PA RD 3, Lewisburg, PA (Chester Co) (610) 869-8834 (717) 568-1420 □ * □ •
Significant historical Pennsylvania newspapers