to: seat it in its@ -,@alve@ seat 51- Any-- flowj of fluid through- the line@ 541 iiL the direction of the: arrow, therein unseats the, valve- member 51" and@ allows fluid@ to flow thereby ancl through. the passageways-48' on into. the tube 41- and thence within the exchange chamber 12 to dispensing tube iL3. In@ Figures 1- and 6 it will be observed; that the handpiece 11 has attached thereto elongated pockets, 55 and 56. which have a tapered recess therein as@ indicated at 55' to, receive the shank- 16' or 17' respectively on the mirror adapte,r 16a or tongue depressor- 17,-. The shanks 16' and- 17,! are held@in by frictionzfit and:the mirror or tongue depressor may be easily oriented into any position desired. Referring to Figs. @ 12 and@ 13 @ it- wiR, be observed that in Fil-. 12 the flexible lines 54 and: 54' have foot-operated valves 57 and 57' therein which@ have foot actuators as indicated@ at 57a and. 57a'. In Fig. 13 the flexible Enes 54, and@.54' in place of having foot valve actuators connected direct in the lines, the lines are:connected@through solenoid operated valves 58 and 58' mounted on the dental, engine and having electrical@ leads to- their respeetive solenoids li@ading down to foot actuator switches 58a and 58a' which are within easy reach of the dentisf s foot. T-he normal switch control for the dental en.-ine is located on the floor adjacent the valve actuator switches or-valve, actuators. In Fi,-. 10, the mirror 16 is positioned, in- one of the pockets 55: or 561 of the hand-piece and'it projects in suspended: relqtion alongside of the tube 13 and the head 14 in an adjusted position to permit of: operation on the tooth in the upper arch in the mouthz of a patient@ The nozzle 15 is positioned closely adjacent@ the tooth. under operation and pointed so as to project coolant against the t6oth so that it runs down the side of the tooth and the adjacent roof -of the mouth by capillary action in a direetion@ away from the mirror. The mirror is not splashed or fo,-@,-d and an uninterrapted operation on the tooth may@ be performed. Such operation may involve the cuttinof- a tooth for a MEng- or otherwise and the coolant i@ needed to- eliminate the heat caused by the high speed cuttin@ Without- removing either instrument from the mouth of the- patient, the dentist can wash the- field of operation and dry same by merely usin.- his foot control of--the@ air and water as supplied to the dispensin.- head 14. In Fig. 11 there is illustrated the use of the tongue depressor 1-7 to hold the tongue away from, the- operatin.@ field and the use- of the. head 14 so arran.-ed w-@'th the nozzle 15 that air is projected continuously through the interproximal space IP to blowaway. any moisture. before it seeps in under the matrix band MB positioned around tooth T to receive a fffling in cavity F. This is only partiafly irustrative of the ability of this instrument to reach into the field of operation for either delivering water for wash or coolin.- purposes free of air for drying purposes. In clinical practice the deevery of compressed air through a dispensing instrument maintained in the left hand, has simplified many operations. In scalin.- operations, under the gum line, a blast of air of sufficient pressure to reflect the free gum line, gives a clear, dry field. Blood and saliva which normally tend to seep into the area are kept back by the constant air flow. This is effective only because the dispensing instrument according to my invention permits the nozzle tip to reach down into the free gum area. Further use of a dried field for which my dispensina instrument is extremely well adapted to serve is in the placin.- of the amal.-am and silicate restorations. In such placin.- it is extremely important that the cavity surfaces are dry and it is especially difficult to maintain a dry field in the lower arch of the mouth, but with this inst.-ument such a dry field may be maintained. When placing restoration below the gum line where blood and saliva mit. the@ packing of the restoration in@ a nioi@ture-freeaimosphere by the use of this dispensing- instrument. This dispensing instrument. is especiahy useful in furnishing at the point of operation a continuous air blast during the. polishing of finished- restorations. As sandpaper discs, steel finishin,-: burrsand:other. polishiiig; agents NvDrk: best in, a dry- field the constant flow of air directed at, the, proper field@ blo@s away any: shavings or saliva that might@ tend to retard@ the polishing% operation. io My dispensing instrument is well, adapted to dispense air wnich has a, cooling effoct in metal restorations@ which absorb I and@ reflect an unc@omfortable amount of heat from the friction of polishing agents. It is, noted@ in clinical use that the blast. of air readily Eipplied under- controlled 1 5 conditions reduce the discomfort; to the patient during such polishing operations. Individual impressions of teeth:may be cooled-by use of my: dispensin.@ instrument as the cooling water may be appliod at the point and in the amount; desired. H@re20 tofore, such coolin.- has had to be accomplished@ by. a hand@ syringe, but again, the quiet flow of water directed by- my- dispensin- instrunient against the point of operation. so, that it flows by capillary action afford maxiinum coolin- with no attendant detrimental splashing. 25 With the development of my dental instrument there is provided for the left hand@ a light-weight easily handled tool which may alternately function by foot@ controued valves as a coolant dispenser for high-speed cutting and as a. dry air dispenser for examination, scaling and@ filling 30 teeth@ As a- coolant dispenser, it will deliver water clbse to the field- of operation making use of capirary@ action- to carry- the water over the field'. This eliminates splash and: provides- a- quiet washin.-- action in which visibiliiy 35 is not: impaired. When used with the niirror attachment the mirror is not splashed or fogged. When used with the ton,-Ue depressor attachment, it provides- forprotection of the tongue durina high speed operations and- it also may function as a cheek retractor if conditions de40 mand. The instrument, according to my invention, may be provided in quantities at low cost so that@ each dentist may be equipped with a number of such instruments. T-he instrument is easily sterilized by either boiling-, autoclav45 in.-, or by immersion in cold sterilizing solutions. Through repeated clinical use this instrument has proved itself, to be. a- most efficient instrument superi6r to anything. known to exist or disclosed in the prior art. !-claim as my invention-. 50 1. A dental instrument of the class de-scribed: compnsin- in combination an elongated dispensin.- tube having a low-,r and an upper end aDd a hand gr?.sp outer portion thereon positioned toward the upper end, a dispensing head mounted on the lower end of said dispensing tube 55 and having a portion thereof swivehy mounted on the balance of said head a dispensing nozzle on said swivehy mounted portion of the head and in dispensing communication therewith, an exchan,-e chamber having a passageway therethrough rotatably rnounted on the upper end 60 of said dispensing tube and having its passa,@eway in cominunication with the passageway in said dispensing tube whereby the dispensing tube may be rotated with respect to sa;d exchange chamber to adjust the position of said dispensing head and the nozzle carried thereby, said 65 exchange chamber having a gas and a liquid passageway connected with the passa.-eway therein and leading to the outside of said exchange chamber and a conduit havin.@ a cheek vaive assembly connected with each of said passageways on the outside of said exchange chamber, 70 said conduit havin- a cheek valve assembly being adapted to be connected with -as and liquid supply Enes leadin.to said instrument whereby fluid may be introduced into said exchange chamber and the dispensing tube without fiuid from one conduit feeding back into the other conseepa.ae presents problems, a continuous air ff ow will per- 7,5 duit past said cheek valve.

7 2.. A dental instrument of the class described compiising in combination an elohgated dispensin-. tube, a tubu-lar hand-piece mounted on the upper portion of said - dispensing tube, a dispensing head mounted 6n the lower end of said dispensing tube, said dispensin.- head having a portion thereof mounted thereon for swivel movenient on the rest of said head, a dispensing nozzle on said swivelly mounted portion of the head and in dispensin.comrnunication therewith, and an exchange chamber havmg a passageway therein and being, adapted to have -as and liquid supply lines attacbed thereto, said dispensin.tube being connected,at its upper end to said exchange chamber for rotary movement with respect thereto ai2d being in co-rnmunication with the passageway therein. 3. A. dental instrument of the class described comprising in combination an elongated dispensin.- tube having a lower and an upper end and a hand grasp outer portion thereon positioned toward the upper end, a dispensing head mounted on 'Lhe lower end of said dispensing tube and an exchan,@e chamber having a passa,-eway theretliiough and openings adapted to have gas and liquid sup.ply lines attached thereto, said dispensin2 tube being connected at its upper end to said exchange chamber for rotary movement with respect thereto and bein.- in communication with the passageway therein, said dispensing head havin.- a cylindrical base formed with an annular passageway therein cut into a i'ace th--reof and forming a central cylindrical boss, said base having a wafl thereof apertured to receive the lower end of said dispensing tube which comniunicates with said anniilar recess, said base being- fixed to sa;d tubular member to form an obtuse an,-le therewith of approximately 165 degrees, a cap member of like co-rifl,-Uration to said base, means swivery connectin.- said cap and base with their faces in abuttin.relationship, sealing means between @aid cap and base to prevent leaka,-e and a nozzle attached to said cap and extendin.- radially therefrom and from said annular passage therein with viliich it is in communication. 4. A dental instrument of the class described comprising in combination an elon.- ated dispensin.- tube havin.a lower and an upper end, a tubular hand grasp member received ovcr the upper portion of said tubLIar member perniitting the upper end of the dispensin.- tube to project -therefroin, securin- means on said tube cooperating with - said tubular hand -rasp member to hold it in adjusted rotated position on said dispensin.- tube, said tubular hand grasp member having at least one pocket member attached thereto in approximate parahol relationship thereto at the lower end and being adapted to receive 2,809,429 8 able dental mirror or tongue depressoi, @ dispensing he@d mounted on the lower end of:.,said dispensing tube and having a portion thereof swivelly mounted on the balance of said h-@ad, a dispensing gozzle oii said swivelly mounted portion of- the head and in dispefisiiig coniiilunication therenvith, and an exchange chamber having -a passage-. way therethrbugh rotatably mounted bn the upper end of said dispensin.- tube and having its passageway in commu-@iication with th& passageway in said dispensing tube whereby ttie dispensing tube and the hand grasp tubular ineniber carried thereby may be rotated with respect to sa-d exchange chamber, said exchange chamber being adapted to have gas and liquid supply lines attach&d thereto. 15 5. A dental instrumeiit according to @claim 4 wheiein said exchange charnber, comprises a cylindrical outer member having a pair bf openings through the waR therein adapted to be connec@ted to conduit and check valve assemblies, a central (@ore member received in said 20 outer cylindrical member having a T-shaped head at one end with a threaded axial recess therein to receive the upper end of said dispen@ing tube, a threaded axial recess in the other end receiving a sectiring cap screw holding thd core in the cyhndrical @ outer member, said core hav25 ing an axial passageway therein in ali,-nment an d,communication with said Lipper end of said dispensing tube received therein and radial ports intermediate the ends of said core communicating with an annular recess formed about the core member, and a conduit and check valve 30 assembly connected with each of said openings in the waU of said cylindrical outer member. 6. A dental instrument according to claim 5 wherein said dispensing head comprises a,cylindrical base formed with an annidar passageway therein cut into a face thereof 35 and forming a central cylindrical base, said base having a waH thoreof apertured to receive the lower end of said dispensing tube which communicates with said annular recess, said bas-- being fixed to sa,d tubular member to forin an obtase angle therewith of approximately 165 de-10 grees, a cap member of like configuration to said base, means swiveny connecting said cap and base with their faces in abutting relationship, sealing means between said cap and base to prevent leakage, and a nozzle attached to said cap and extending radially therefrom and from said 45 annular passage I therein with which it is in communication. References Cited in the file of this patent UNITED STATES PATENTS therein the shank of a detachable and adjustably position5( 851,483 Bartlett ------- -- ------ Apr. 23, 1907

2 9 8 0 9 , 4 2 9 Uni'ted States Patent office Patented Oct. 15, 1957 2,809,429@ 5 DENTAL INSTRUMENT- ASSEVIBLY Albert R. Cerveris, Pittsbur.-h, Pa. Appjication May. 2-1, 1956, Serial No. 586,124 6 Claims. (Cl. 32-33) 10 My invention is directed, to in-iprovements in a gas and 1,5 liquid dispelsin- dental instrument with assoc-lated mirror and ton,-ue depressor for use in the oral cavity. With the, continued increase in perfection and use of high speed -dental drifls there is need for improved and adequate- liqui@d and gas dispensers, to wash, cool, and 20 dry at and praximal to the point of operation. Adequa'Le means 4re available- to evacuate the 1:tquid wdsh and coola@it but an improved instrument is needed for us,- by thp- de@itist in his left hand while he uses the usual hand-piece in his right hand. An :instrainent ac- 25 cordin- to. my invention serves to fill this need foT a means to apply wash and coohng liquid and drying and. motivatin@ compressed gas. at the point r quired and in the marmer and at th.- time desired, all of which is directly under contre@l of the dentist. Such an instru- 30 ment that will adequately dispense .-as and liquid and has the approximate bulk of the usual dental mirror and pro-,,ides for the uses. afforded by such mirror is provided in the instxument accordin to my invention. - @g it is, an object of the invention to provide a dental 35 instrument adapted to b@- used by@ the dentist @in his left hand for 4pplication in the oral cavity and tbat. has the apprcximate bulk of a dental mirror yet p)rovides for controlled applica.tion of cooling and waswng liquid and gas. in a field of operation, without any interference,. with 40 the operation and at the same time permits use of a dental mirror that ma-y be associated thereviith witholt its be.-ominfo-ged or splashed. Another object of my invention is to provide, a dental instrument of the approximate size of a dental. mirror 45 which permits application of liquid and gas at a selected field of pperation and-, at the same tim@- permits of the coop,erating use of a d.-ntal mirror or tongue deprmor y,et is easily fabricated. at 1 w cost so that a number I Q may be emp C@ joyed by- th dentist and at the same time -50 each suc4- instrument is easily detached fro-@n its associated connections forsterilization. A- fuol@er obect of nly, invention is to- provide: in a dental instr4iii@ent- oz dispensing gas and liqiiid, a swivehy 55 molinl,ed, dis ens,n- nozzle which. p@armifs the control ... I p of- the: dire @ction of application. of such fluid in, a dental @op ,-pT4aon a t a desij-.ed point or field without causin- any @pl@shinAnother Q@@ject of m invention is, to provide a den_y tal, instrumqnt for a -sire4 pioint so 60 -pplyiga fluid at a,. de tjaa.t the f@'uid in, cas . i@ is a liquict may: l@e applied to the a-di4qQpt tooth oT mouth p.ort@on such that it flows by capillary- a@-tion. and performs a. coolin@ and@ washina f-unction. A fur@her object of ni-y- inventi@on is to, providf, a, dental 65 instrument with a- dispensin- heacl. for applyipg fluid and. whi@;h may carty! a rei)laceable@ ton.-ue di@penser@ or an easily replajqeable-dental rnirror- and wherein. the head, mir.r,or. or- to4gue, depressor are-- read.ily adjqstc@d for the 70 moo - efficient: use- in c4rryin- ou a dental operation. A still. further obiqct of iny inveation is to provide, 2 a dental instrumeiqt for use, by the dentist in his left hand which wiR apply seleletively wash and cooling liquid or compressed air in a controlled mann.er to so assist in a,,dental operation that the operating time is reduced a @marked amount and the patient is at the-. same time afforded more comforl. StiR further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter., It should be understood, however@ that the detailed description and specific examples are given by way of ihustration only and, while indicating preferredembodiments of the invention, are not given by way of limitation, since various changes- and modifications within, the spirit and scope of the invention will become, apparent to those skilled in the art from this detailed description. For a more comple,te understanding of the nature and scope of my invention reference may be had to the dra-,vings in- which: Fig. 1 is a top plan view of the dental instrument assembly; Fig. @ is a top plan view of the instrument in Fig. 1 with nlirror removcd and on an enlarged scale; Fig. 3, is a slightly enlarged cross sectional view along line 3-3 of Fi@. 1; Fig. 4 is an enlarged cross sectional view of the head of the, instrument along line 4-4 of, Fig. 1; Fig. 5 is a cross sectional view. alon.- line 5-5 of Fig. 4; Fig. 6@ i-s a fragmc@ntary cross sectional view sh,olwing a socket mounting for a mirror or a tongue depressor alon@ line 6-6 of Fig. 2 on an enlarged scale-, -Fig. 7 is an enlarged cross sectional view of the exchan,-e chamber of the instrument alona. line 7-7, of Fig. 1; Fig. 8 is a view of a mirror adadted' to be removalbly attached to the instrument; Fig-. 9 is a plan view of a tongw depre@@sor adapted to be repiaccably attached to the instrument, Fig. 10 is a perspective view of the instrum,ent with niirror attached in use on an upppr tooth to apply liqtiid; Fig. 11 is a perspective vic@w. showing the use of the instrument with ton-,ue d,er)ressor in use in applying air under pressure in a tooth-i'ifling oppration to prevent seepage under a matrix band; Fi,@. 12 is a schematic partial view of the gas- and liquid lines lead;ng to the instrument, and Fig. 13 is a schematic view of solenoid actuated valves in the@ gas and liquid lines leading to. the instrument. Throughout the description like Tefpren.cp num c@rals refer to similar parts. The dental instrum.-nt according to my, invention: is gener-.ally indicated at 10 and comprises i,n general the, handpie@ce- 1-1 detachably connected to the exchanchamber @e 12 at one end and having a dispensing tube leadin there9 through and out the other end as at 13 having attached to its outer end a dispensinhead@ 14 for gas and liquid. This instrument 10 has the -ene,ral shape and bulk of the normal dental niirror which is customar.ilv manii)ulated by the dentist in his left hand when operating. The usual dental mirror is used as a depressor and retract,or along with its main use as a mirror Nvhen operating on the upper teeth in the oral cavity. I have made available in my dental instrument an instrument of about the bulk of the usual dental mirror with its handle and provided therein a dispensing means for compressed air and coolant liquid which may be readily used by the dentist without impairing his use of his left hand to hold at the same time- a mirror or a tongue depressor or the like. Thus, the, dentist is able to accomplish dental operations in a mozc expeditious manner and with- more comfort to the

2,809,429 3 patient. Two uses are illustrated in Figures 10 and 11 for the instrument as examples of some of its many uses and its facility of usal-C. In designin- and clinically using this instrument, it has been the primary objective of the development to have a li.-ht-wei.-ht instrument which may be easily sterilized, is not bulky and yet provides for application of either compressed gas or coolant liquid along with the use of a mirror or a tongue depressor. Applicant is aware of prior devices for carrying out some of these features but .not with the facility and with the control oi' applying the cooling fluid at the point or field desired and at the same time not splashing the mirror or causing it to fog. The dispedsing head 14 and its nozzle 15 may be read y adjusted to any particular attitude with reference to the hand -piece 11 and the mirror 16 or the tongue depressor 17 when either is in place. The dispensing tube 13 has an upper threaded end 13' and receives thereover the tubular hand-piece 11 having aperturcd end pieces 11' and 11" which receive the tube 13 in sliding engagement. Dispensing tube 13 is about 5 inches in length while the overall len.-th of 'Lhe instrument is about 61/2 inches which is the overall length of the usual dental mirror. Spaced in from the lower end of the tube 13, namely, the head end thereof, there is attached in fixed engagement with the tube 13 a conicallike shaped stop 18 a,-ainst which the hand-piece tube 11 rests. This stop piece 18 is knurled as at 18', see Fig. 1, where it engages with the closed-off end 11' of hand-piece 11. The other end 11" of the hand-piece 11 is slightly recessed to receive a knurled nut 19 having an inwardly tapered outer surface to be received within the end of tubular hand-piece 11 adjacent the inset closed end 11" so as to be ti,-htened thereagainst and to set the hand.piece tube 11 a.-ainst the knurled stop 13 so as to hold it firmly in any selected position of the dispensing tube 13 therein. This is important when it is necessary to orient the hand-piece 11 to position the mirror and ton,-Ue depressor carrying sockets 55 and 56 with respect to the head 14 of tube 13. The dispensing head 14 is arran,-ed in fixed engagement on !he end of tube 13 at an angle of about 165' as indicated at A in Fig. 3. It has been found that this an,-Ular attitude of the head which has a swivel connect,ion as will be described serves admirably in all positions of desired use. The head 14 comprises a base portion 20-of cylindrical shape which is apertured at 21 to receive the end of tube 13 which provides a connection with an annular passageway 22 formed in the base 20 from its inner face 20'. An annular boss 23 is formed by the annular passageway 22 and it has a cutaway shoulder 23', see Fig. 4, and an annular semi-circular recess 24 formed in the annular face 20' to receive an 0-rin.- packing. As an alternative construction, this 0-ring packing may be formed of the metal or it may be a protruding semicircular portion of the base 20. The boss 23 has a central recess which is thieaded as at 23" to receive a cap screw as will be described. To complete the swivel head 14 there is a cooperating cap 25 of like shape to the base 20 and havin.- an annular recess 26 cooperating with the recess 22. A central boss 27 is formed by the annular recess 26 and it has a shoulder portion 27' thereon cooperating with the shoulder 23' and apertured at 28' to receive a securing cap screw 28 which is received within a recess 29 formed in the cap 25@ In the wall of the cap 25 there is an aperture 30 extending therethrough which connects with the nozzle 15 which is set into the cap 25 in the recess 25" so that it projects out in a radial manner such as shown in Fi,-. 1. The cap 25 is formed with a semi@circular cooperating recess 25' in the face thereof to receive the 0-ring 24. In this construction of the head 14 it wiE be noted that the cap 25 carrying the radially projecting nozzle 15 may swivel through 360 de.-rees and in any set position willdispense fluid throu,-h the nozzle 4 ing of the tubular member 13 within the hand-piece 11, the tubular mcinber 13 may be oriented by merely loosening up of the knurled nut 19 so that the handpiece may be rotated above the tubular member 13. The tubular member 13 may be rotated to move the head 14 by means of its threaded end 13'. The hand-piece 11 and the tube 13 form a unit and are received in the threaded end of the exchange chamber 12. The exchan.- e chamber 12 serves the purpose of con10 ductin.- gas or a liquid to the tube 13 leading to head 14. This exchan.- e chamber 12 is formed with an outer cylindric al sleeve 31 which receives therein a core mernber 32 having a hoflow passage way 32' extendin g longitudi nally therein and connecti ng with a threaded aperture 33 15 in the end cap 34 thereof. The aperture 33 receives the threaded end 13' of the tube 13 in tightfitting enga,@e ment so that -@io leaks occur. Passage way 32' extendin g Ion.- itudinally of the core member 32 is undercut a s ght amount so that its bore is of about the same diameter 20 as the internal diameter of the tubular member 13 permittin g smooth flow of the fluid into the tube, 13. Core member 32 is formed with radial aperture s 35 which connect with an annular recess 36 formed about the circumfe rence thereof. The core member 32 has a plurality of 25 spacedapart circumfe rential recesses 37 forined therein to receive packin, @ 38 therein of composit ion material. The opposite end member to the head 34 of the core member 32 is formed with a shoulder 39 and it has a central recess aperture 40 formed therein whch is 30 threaded . Receive d over the shoulder portion 39 is the end washer 41 and against this there bears the cap screw 42 which is received in the threaded recess 40. Betwee n the head 34 and the outer cylindric al portion 31 there is a fiber washer 43 which fornis a seal at that end. It will 35 be noted that the out@-r portion of the cap 34 as sbo@vn in Fig. I is knurled so that the core member 32 may be rotated Nvithin the sleeve 31. It will be noted that the outer tubular portion or sleeve 31 is so mounted that it may be rotated on the central core 32 and stih fluid will 40 pass through the radial aperture s 35 on into the central core 32' from the circumfe rential passage way 36. Connectin- t the passageway 36 and the outer sleeve 31 which is provided @vith suitable adertures are tubular members 44 and 45. Each of these tubular members 44 45 and 45 extends in bifurcated arran,@eme nt transverse and -outward frori the exchange chamber 12 as shown in Fig. 7. These tubular members 44 and 45 diverge outward at their outer ends where they are attached to a cylindrical fitting - enerally indicated at 46 coinpiising a 50 cylind rical cupshape d end 47 having fixed therei n as by solderi ng a core 48 provid ed with longitu dinal space dapart apertu res 48' exten ding theret hroug h and a centra l apertu re 49 while the outer end of the core 48 exten ds out beyon d the cap 47 and is thread ed to receiv e a 55- similar cap 50 having a thread ed inner portio n 50' which abuts agains t a washe r 51 placed over the core 48 and receiv ed betwe en the adjace nt ends of the memb ers 47 and 50 to form a seal. Recei ved within the centra l bore 49 of the core 48 is a valve stem 51' of the valve gen60 erahy indicated at 51 and having a conical head 51" and a guide 51a. ne head 51" is received within an aperture d and conical recess 52' formed in a valve seat 52 seated in the bottom end of the cap member 50. The bottom end of the cap member 50 is connect ed by a tube 53 having an intumed end 53' which receives a flexible hose connecti on 54 that may be attached to the air supply or the liquid supply as desired. A similar member to 46 is indicated at 46' and it serves the same purpose as the member 46, namely, as a check valve to prevent reverse TO flow of fluid in the lines 54-54'. The arrow shown in Fig. 7 in each of these Enes is the normal direction of flow of the fluid in each of the lines through the check valves 46'. Thus, it will be observed in the cutaway portion in Fig. 7 of the check valve 46 that any reverse 15 as wW hereinafter, be described. So also in the mount@5 flow will act against the planar face of tho valve raember