SEAL FACE SEAL FACE PROPERTIESPROPERTIES FOR A SEAL TO WORKFOR A SEAL TO WORKFACE FLATNESSFACE FLATNESSSEAL FACES ARE TO BE FLAT TO ONE SEAL FACES ARE TO BE FLAT TO ONE LIGHT BAND OF A HEILIUM ARC LAMP LIGHT BAND OF A HEILIUM ARC LAMP REFLECTED THROUGH A QUARTZ REFLECTED THROUGH A QUARTZ REFERENCE OPTICAL FLATREFERENCE OPTICAL FLATONE LIGHT BAND = 0.0000116 INCHES ONE LIGHT BAND = 0.0000116 INCHES OR 11.6 ONE MILLIONTHS OF AN INCHOR 11.6 ONE MILLIONTHS OF AN INCH Opt!"##$ F#"t F"!%&100 p&0 p&R't"($F"!%St"t')"($F"!% FOR A SEAL TO WORKFACE LUBRICATIONBOUNDAR* LA*ER FILM OF LIQUID FILLS PORES AND IMPERFECTIONS.IT IS PRO+IDED B* THE LIQUID IN THE STUFFING BO,.DR* RUNNING OF A PUMP SEAL FOR ONL* A FEW SECONDS MA* DESTRO* IT.UNLESS IT IS DESIGNED THAT WA*- M!('&!'p! F"!% L./(!"t')100 p&0 p&R't"($F"!%St"t')"($F"!% P(%&&.(% D('p100 p&0 p& 100 p&0 p&01 p&10 p&L2.3L2.3 4 +"p'(+"p'( 4 L2.3+"p'(P(%&&.(% D('p 5 P(%&&.(% D('p 5 +"p'(6"t')+"p'(6"t') C')7%(8%)t S%"# F"!%&100 p&0 p&R't"($F"!%St"t')"($F"!% C')7%(8%)t S%"# F"!%&100 p&0 p&R't"($F"!%St"t')"($F"!% C')7%(8%)t S%"# F"!%&100 p&0 p&R't"($F"!%St"t')"($F"!% D7%(8%)t S%"# F"!%&100 p&0 p&R't"($F"!%St"t')"($F"!% D7%(8%)t S%"# F"!%&100 p&0 p&R't"($F"!%St"t')"($F"!% D7%(8%)t S%"# F"!%&100 p&0 p&R't"($F"!%St"t')"($F"!% SEAL BALANCE B"#")!% L

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)% BALANCED +S. NON9BALANCEDBALANCED +S. NON9BALANCED When speaking of Balance in reference to mechanical seals, we are not talking about Mechanical or Rotational Balance. Instead, we are referring to !draulic Balance. "ince mechanical seals are sub#ect to stuffing bo$ pressure, this pressure is utili%ed to achie&e and maintain seal face closure in a non'balanced seal. If stuffing bo$ pressure is &er! high, t!picall! o&er ())psi., then the closing force ma! be too great to allow the Boundar! *a!er *i+uid that lubricates the faces to be sufficient and the faces will wear prematurel!. , balanced seal compensates for higher pressures b! locating the seal faces such that stuffing bo$ pressure has less effect on face closure. S%"# B"#")!% B"#")!% L

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)%, non'balanced seal has faces locatedoutside the Balance -iameter of theseal. "tuffing bo$ pressure is appliedto the faces &irtuall! e&enl!. F"!% OD L

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)%.nbalanced "eal/ace ,reasG(%%)4R%3=P(%&&.(% A(%"G(%%)4P.(p#%=F"!% C')t"!t A(%" F"!% OD L

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)%0he faces of a balanced seal are located so thata portion of the face contact occurs inside the balance diameter resulting in reduced closingforce due to stuffing bo$ pressure. Balanced "eal/ace ,reasF"!% OD L

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)%B"#")!% L)%G(%%)4R%3=P(%&&.(% A(%"R%34P.(p#%=B"#")!%3 A(%" Most metal bellows seals are balanced.F"!% OD L

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)% ENDENDSEAL FACE SEAL FACE PROPERTIESPROPERTIES