Water Well Journal

July 2015

Water Well Journal

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fluid contaminant risk, this is the pre- ferred method in most potable water applications. The lineshaft bearings are enclosed in bronze or cast iron retainer brackets often referred to as "spiders." Disadvantages of this method include inability to run without lubrication for any period of time; the need to pre- lubricate the bearings when the static water level is deeper than 50 feet; a high factor of wear in abrasive conditions; a concern the rubber bearings will de- velop stiffness, cracking, and dryness during prolonged periods of non-use; the relative long spacing between bear- ings and excessive wear that can cause shaft whipping, resulting in vibration and bent lineshafts; and high lateral wearing in crooked or misaligned wells. Oil-lubricated bearings are installed in an outer steel tube that encloses the actual drive lineshaft. These bearings, which are generally constructed from bronze, are usually spaced at intervals of 3 feet or 5 feet. Turbine (petroleum based) or food-grade type oil is gener- ally used to lubricate this style of bearing. Since the bearings are closely spaced and sealed and are isolated from the pumped fluid, they provide excellent wearing and alignment features in wells with deep water levels, crooked wells, or wells with large quantities of sand and usually do not require any type of pre-lubrication. The constant need to continually introduce lubricating oil into the well and the risk of oil leakage into the well reflect obvious disadvantages of this method, so their use in potable water applications is extremely limited. In past years, the type of lubrication was often associated with the applica- tion of the pump. Agricultural irrigation and industrial turbine pumps frequently used the oil-lubricated style while mu- nicipal or water supply applications used water-lubricated VTPs. In recent years, as concern regarding possible well and aquifer contamination increased, the use of the petroleum oil type of lubrication has diminished ex- cept in deep wells. Food-grade oil, espe- cially vegetable oil, has supplanted the use of petroleum-based lubricants and is now used on many public water supply well pumps. Discharge Head The term discharge head is used to describe the support base located at the top of the well. The head is used to sus- pend the entire bowl, column, and line- shaft assembly as well as support the selected driver. This head is usually con- structed from cast iron. However, fabri- cated steel heads are sometimes used on deep or high-pressure applications. Most deep well applications use a series of packing rings to seal the shaft surface where it exits the discharge head, although special mechanical seals are often used in booster pumps or very clean water applications. In the next installment of The Water Works, we'll continue with a discussion on submersible pumps. Until then, keep them pumping! WWJ Ed Butts, PE, CPI, is the chief engineer at 4B Engineering & Consulting, Salem, Oregon. He has more than 35 years experience in the water well business, specializing in engineer- ing and business management. He can be reached at epbpe@juno.com. c ear S , ts a r er all t m alar olume c air v ippers air str gers air char s t y tion equipmen a aer ope , r ers adapt A em o r igs t to om r r F c c c Se c ar ear ear Sear S o o f ching f c c n c cir th mill t t oduct media r tion at om om om clam chlo chem chem chec o o o o o ching f ching ching f hi f g f g ching f or some or some or so or or some or some me r some or so ething? ething? g g? ething? ething ething? ething? ? casin casin casin i tion wheels ic , fr ool , cable t bits ds , cable guar bits on , butt bits inders r bit g ool essers and t bit dr e pe onit t ben ings bear in bank bailers B a aug aug AS ar ers Buy ir A D NGW or ser ou , nd th e y vic d th ig es vic ser g om r r F dec da D c cr c c or c or c on on c on c n c c eel ed st t ica , fabr ngs , spiders & slips ools ng t wnhole do - er ng cutt ers h) le or t . uide s G y & need in the or t ect r & the pr t oduct the p eed o deaer ta ylin an ou ou e e v t t t ond om om u u n Guid e Buy Onlin de rs ne i n d F t en c th ca casin casin casin casin casin casin casin casin tal on iz , hor bits ill , dr bits ag , dr bits -hole wn-the , do bits , diamond bits bide , car bits ems , st ool , cable t bits , sockets ool , cable t bits , jars ool , cable t bits tion wheels ic , fr ool , cable t bits i t a dir der dec ers aliz r eads eaded PVC , thr ngs eon , T ngs eel , stainless st ngs , shoe ngs , PVC ngs , plastic ngs glass , ber ngs eel ed st t ica , fabr ngs t N G W e dies desilt desanders desalina r depth indica deioniza equ o u Guid de WWJ July 2015 59 Twitter @WaterWellJournl

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