US3482313A - Oral vacuum system - Google Patents

Description

Dec. 9,1969 G. HA STRAM 3,482,313

ORAL VACUUM SYS TEM Filed` April 12 1967 4 Sheets-Sheet l IMul" I' ..Ilnl'm' /za ...MP `Il 'lm L -33 l'r ,N l l@ i 4e se 74 s4 1|| 4e i Il L v l2 i 32 8.4 l "I" Y' l* 9Y72- I lo 54 hl- QF- flfs GEORGE H. STRAM ATTORNEY Dec. 9, 1969 G, H sTRAM 3,482,313

ORAL VACUUM SYSTEM Filed April l12 1967 l4 sheets-sheet 2 FIG.4

INVENTOR GEORGE H. STRAM mfL h ATTORNEY Dec. 9, 41969 cs. H. sTRAM 3,482,313

' 4 ORAL VACUUM SYSTEM Filed April 12 196'? 4 Sheets-Sheet 5 INVENTOR y GEORGEl H. STRAM i ATTORNEY Dec; 9, 1969 H@ STRAM 3,482,313

lORAL VACUUM SYSTEM Filed April 12, 19e? 4 sheets-sheet 4 INVENTOR GEORGE HSTRAM BY j f ATTORNEY United States Patent O 3,482,313 ORAL VACUUM SYSTEM George H. Stram, Hellam, Pa., assignor, by mesne assignments, to Dentsply International Inc., York, Pa., a corporation of Delaware Filed Apr. 12, 1967, Ser. No. 630,398 Int. Cl. A61c 1 7 04 U.S. Cl. 32-33 9 Claims ABSTRACT OF THE DISCLOSURE Oral vacuum system including an oral evacuator handpiece, saliv-a ejector and/or cuspidor connected to liquid ring pump by flexible hoses, the capacity of the pump relative to the size of the flexible tubes producing high vacuum with a relatively low volume of air, permitting use of a small diameter suction tube which can readily be coiled upon a reel. A safety relief valve is located directly in the suction handpiece to limit the vacuum level and incidentally permitting purging of the tube even if stoppage at the nozzle occurs.

CROSS-REFERENCE TO RELATED APPLICATION Application, Ser. No. 498,547, led Oct. 20, 1965, Thornton et al., relates to a Dental Console having facilities to accommodate a vacuum system of the type to which the present invention pertains. Patent No. 3,280,- 458, dated Oct. 25, 1966, also relates to a Dental Equipment Stand and shows, somewhat broadly, means to accommodate a vacuum system of the type to which the present invention pertains. Also, Patent No. 3,295,148, dated I an. 3, 1967 pertains to a dental cuspidor of a type which may be attached to the system comprising the present invention.

BACKGROUND OF THE INVENTION For many years, suction systems of low capacity have been utilized by dentists in connection with saliva ejectors which require only a low range of suction to withdraw very limited quantities of uid, such as saliva, from the oral cavity of a patient. In an effort to provide greater patient comfort during the past several decades, attention has been focused upon pain resulting from the heat generated by dental burs and the like while cutting and drilling teeth, llings, etc. The provisions of cooling water sprays in association with such operations has partly solved this problem but has created a need for greater evacuation capacity. The relatively recent advent of high speed handpieces for drilling and cutting during the past decade has required even greater need for cooling and flushing spray Water, as well as means to withdraw such greater quantities of water in which an appreciable amount of cut or ground solid material is entrained from such high speed operation. Such high speed operations also result in the water spray being broken up into a clouding mist which must also be evacuated so the dentist can suitably view his operations.

To meet such increasing need for evacuating greater quantities of mist and liquid with entrained solids from the oral cavity, evacuating units and systems of greater capacity than those used heretofore have been devised and customarily are employed during most if not all of the drilling or cutting operations. Typical examples of such current type of evacuating units are illustrated in U.S. Patents Nos. 3,012,322 and 3,012,323, dated Dec. l2, 1961. The source of suction in such system is the standard air fan of a well known type of domestic vacuum cleaner which has a maximum capacity of moving 8 c.f.m. of air and producing a static suction not in excess of inches of mercury. Since the fan is such that liquid cannot be passed fr' j ICC directly through the same, it is necessary to apply the suction effect to a container in a manner to by-pass the fan and this is less efficient than would result from passage directly through the fan incident to passing the discharge to a sewer.

Since the operation of the aforementioned systems also depends upon a relatively low degree of static suction but relatively large volume, the inlet tube from the evacuating nozzle to the solids trap of the system necessarily must be of a relatively large diameter which is such it cannot be effectively or compactly coiled so as readily to store it out of sight when not in use. Accordingly, the tube usually merely hangs in a depending loop from a bracket for the nozzle and the housing of the unit which frequently is supported on the wall of the operatory.

Certain other currently used evacuation systems employ a liquid seal pump only and this requires a suction relief valve located directly at the pump of the system. Said relief valve functions when the inlet end of the evacuator nozzle is closed, as by accidentally engaging tissue such as a cheek or tongue of a patient. Under such circumstances, where the vacuum is of a relatively high range, damage can result to the patient, such as a blister or bruise being caused before the relief valve functions, due to the length of the tube between the pump and nozzle. Further, if the pump is stopped after such an occurrence the tube still contains debris and liquid between the pump and nozzle.

SUMMARY OF THE INVENTION The evacuating system comprising the present invention includes, in combination, a liquid ring pump having a rotor operable in a pump chamber having inlet and outlet ports directly therein and fluids, both liquid and gaseous, which are pumped thereby pass directly through said chamber and are impelled directly by said rotor; a solids trap or collector provided with a conduit which extends between the outlet thereof and said pump inlet port; and a flexible tube or conduit of relatively small diameter, highly capable of being compactly coiled upon a reel to store the same when not in use, which extends from the inlet of said solids trap to an evacuator nozzle or aspirating handpiece unit.

Said unit also includes a nozzle of adequate size readily capable of evacuating substantial quantities of liquid and gaseous iluids, and mist formations thereof, and also solids such as bits of tooth material, metals and the like entrained in such liquid. A relief valve is mounted directly in the handpiece or holder for the nozzle so as to function instantaneously upon stoppage of ow through said nozzle to decrease the suction level to an unharmful range. This minimizes possible injury to the patient and, in addition, permits continuous purging of the entire tube and conduit system as long as the pump functions.

The system also preferably includes a liquid inlet connected to a suitable source and arranged to discharge liquid, such as water, at a predetermined rate continuously into the system, preferably into the inlet means of the solids collector. This supply has the plural objectives of maintaining a liquid wall or seal in said pump, and continuously flowing cleansing fluid through the solids collector container to dissolve soluble waste and thus continuously keep the collector reasonably clean of any waste material. A strainer in the container of the collector prevents solids above a predetermined size from passing to the pump. Said strainer also is readily removable when the container, which is cup-like, is removed from the collector elements. The strainer normally is enclosed in the container when the latter is removed to recover any desired solids, clean the strainer, and discard unwanted, retained solids such as tooth particles. Such cleaning of the strainer may readily be done simply by flushing the same while temporarily held in such cup-like container during such ilushing thereof.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic, diagrammatic view of an exemplary dental evaeuating system embodying the principles of the present invention.

FIGS. 2 and 2a respectively are vertical front and side elevations of an exemplary cabinet containing the liquid ring pump and solids collector illustrated somewhat diagrammatically in FIG. 2a, and also showing exemplary dental instruments supported by said cabinet, including typical suction devices to which the invention pertains.

FIGS. 3 and 4 respectively are enlarged scale side and front elevations of the liquid ring pump, solids collector, and the air and water separator of the system shown in FIG. 1 to illustrate the cooperative relationship thereof in a preferred arrangement.

FIG. 5 is a top plan view of the arrangment shown in FIGS. 3 and 4.

FIG. 6 is an enlarged transverse sectional view of the impeller chamber of the pump shown in the preceding figures as seen on the line 6-6 of FIG. 4.

FIG. 7 is an enlarged vertical sectional view showing details of the solids collector.

FIG. 8 is a fragmentary, partially sectioned side elevation of the base of the evacuator handpiece shown in FIG. 1 which supports the evacuator nozzle, the inner ends of the latter being shown connected to the base of the handpiece.

FIG. 9 is a longitudinally sectioned view of the evacuator handpiece arrangement shown in FIG. 8.

FIG. 10 is a transverse sectional view of the handpiece as seen on the line 10-10 of FIG. 9.

FIG. 11 is a transverse sectional view of part of the relief valve mechanism in the base of the evacuator handpiece shown in FIGS. 8 and 9, as seen on the line 11--11 of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. l, the principal elements of the entire system are described as follows. The liquid ring pump 10, which is sometimes referred to as a liquid seal pump, is driven by a suitable electric motor 12. The pump 10 has an inlet tube or conduit 14 leading from the exit of a sol-ids collector or trap 16. The inlet to the solids trap is a conduit 18 which extends to a hollow, central shaft which communicates with one or more rotary joints 20 associated with several reels 22 and 24 mounted for rotation about the axis of the hollow shaft communicating with the rotary joint 20.

The reel 22 is of suitable size to permit coiling thereon of the ilexible suction tube 26 which communicates with the base member or handle of the evacuator handpiece 28, from which a suitable suction nozzle 30 is connected. The evacuator handpiece 28 has a manual control valve and an automatically operable relief valve therein, details of which are described hereinafter. The nozzle 30 and suction tube 26 are of such size relative to the pumping capacity of the liquid ring pump 10, that appreciable volumes of liquid and debris particles entrained therein are capable of being withdrawn from the oral cavity, the same traveling at a very high rate of speed, especially through the tube 26, which insures continual cleanliness of said tube.

Solid particles of a predetermined minimum size are retained in the solids collector 16 by means to be described in detail hereinafter, while the liquid waste and solids material smaller than said predetermined minimum size are carried through the pump 10 by conduit 31 to a separator 32 wherein liquids and solids are separated from the air introduced into the system through the nozzle 30. The air preferably is discharged to atmosphere after iirst passing through a muffler 34. If available, such discharge might be directed into a suitable stack. Because of the relatively high static suction capacity of pump 10, which makes it possible to utilize a suction tube 26 of relatively small diameter, said suction tube readily is coiled compactly upon a relatively narrow reel 22 of reasonable diameter.

Reel 24 is of suitable size to receive and have coiled thereupon a triple-conduit line 36. As in regard to the suction tube 26 however, the suction capacity imposed upon the system by the relatively high static suction of the pump 10 makes it possible for the diameter of all of the conduits of the line 36 readily to be coiled upon the reel 24 within a relatively compact space. One of the conduits of line 36 leads to the discharge of a portable cuspidor 38 which preferably is held in the hand of the patient. Also extending from the cuspidor is a conduit 40 which is connected at one end to saliva ejector 42 and the opposite end communicates with one of the suction conduits of the line 36. The remaining, third conduit of line 36 is arranged to deliver water to the cuspidor 38 for purposes of continually ushing it while in use. The supply of water to said third conduit is obtained through a conduit 44 and ow is controlled preferably by a solenoid valve 46. The conduit 44 is connected to a suitable source of water at city pressure, for example.

In order that the pump 10 may be insured of a cylindrical wall of liquid such as water around the interior periphery thereof, a supply of water is delivered through conduit 48 leading from a suitable control valve 50, preferably solenoid-actuated, and otherwise connected to a source of water at city pressure, for example. The conduit 48 discharges into the inlet fitting 52 by which conduit 18 is connected to the solids collector 16 for the discharge of liquid and debris thereinto. Such arrangement not only insures delivery of a predetermined amount of water continuously to the pump 10 while it is operating, but results in the additional advantage of liquid waste such as pus, blood, etc. continually being diluted for ready flushing through the collector 16 for delivery to the pump 10 and ultimately for discharge to separator 32, from which liquid waste is expelled to a sewer connection, such as by conduit S4.

LIQUID RING PUMP The basic principles of a liquid ring pump per se are old. Essentially, by reference to FIG. 6 in particular, it will be seen that the pump 10 comprises a cylindrical housing having a circular -inner wall 56. Eccentric to the axis of the inner wall is an impeller shaft 58 to which the hub 60 of the radially bladed impeller 62 is connected for rotation by the electric motor 12. The blades or vanes 64 of the impeller 62 are of uniform length with respect to the axis of shaft 58 which is the drive shaft of motor 12. Due to the introduction of so-called cooling water through the conduit 48 into inlet tting 52 at a relatively small but constant rate when solenoid valve 50 opens incident to suction being desired, said water passes through the solids collector 16 and discharges through inlet conduit 14 to the pump cavity 66. The volume thereof is such that a cylindrical wall of water is constantly moved around the interior of the cavity 66, said wall of water being substantially defined by an inner diagrammatic circle 68. Said wall of water is of substantially uniform thickness and is coaxial with the axis of the cylindrical inner wall 56 but is eccentric to the shaft 58 of impeller 62. This eccentricity is used to advantage for the followmg purposes.

One end of the housing of the pump 10 which defines an end of the pump cavity 66 is provided with an inlet opening 70 and outlet opening 72. The shapes of these cavities are somewhat similar and somewhat resemble onehalf a crescent. As positioned in the end wall of the housing, they are mirror images of each other as viewed in plan view as seen in FIG. 6. 'The area of the inlet opening or port 70 is larger than the area of the outlet opening of port 72. Also, the aforementioned circular wall of water within the cavity 66, as defined by the circular outline 68, is of such thicknses that the tips of the blades I64 all extend into said wall of water a substantial amount but said amounts vary in accordance with the eccentric position of the impeller 62 relative to the cylindrical inner wall 56 of the pump chamber. This also is readily envisioned from FIG. 6. As a result of this arrangement, segmentally shaped spaces 74 occur between successive blades and extend outwardly from the roots thereof. Said spaces are for purposes of entrapping air to cause the apparatus to serve as a pump for lsaid air by functioning in the following manner.

As the segmental space between a pair of blades 64 is moved into communication with the smaller end of the inlet port 70, as viewed approximately at about 4 oclock in FIG. 6, when the impeller is moving lin the direction of the arrow shown in said ligure, said segmental space will rapidly expand radially outward, due to the constant thickness of the wall of water and the increasing width of the inlet port 70, until the larger, trailing end of said inlet port is reached. At this point in the path of movement of any individual pocket of entrapped air, the volume and pressure thereof will remain substantially constant until for a brief period, at about 1l oclock as viewed in said ligure the larger end of the outlet port 72 is reached, at which location the discharge of air from said successive pocket of entrapped air commences. The outer perimeter of the outlet port 72 is substantially coextensive with the inner circular outline 68 of the wall of water within the pump cavity 66 and it will further be seen from FIG. 6 that as said pockets of air continue to move clockwise, said spaces decrease in radial dimension so as to compress the air in the entrapped spaces and thus force the same outward through the outlet port 72, in compressed condition.

The ability of the system to employ a suction tube 26 of such small diameter that it may readily be coiled upon reel 22 is dependent upon the capacity of pump 10. To facilitate coiling tube 26, it is also preferred that the wall of the tube be relatively thin to render it readily flexible. In practice, it has been found that a flexible tube made from rubberlike material and having an inner diameter of approximately 5/16 and an outer diameter of approximately 1/2 is well suited to the system described above to achieve the result of the pump producing a relatively high static suction, at the pump, but the static suciton at nozzle 30 being limited to a suitably safe level.

As an exemplary but non-restricting illustration of the system, when the pump is driven at a normal speed of 3450 r.p.m. by a 3%; h.p. motor, it develops a static pressure of between approximately and 12 of mercury at the pump inlet. The air volume capacity is not appreciably in excess of 6 cu. ft. per minute under such circumstances. The static suction at the nozzle inlet is approximately 8 of mercury.

The principal advantage of the type of operation described above which involves relatively high static suction pressure to withdraw relatively low volumes of air is that a flexible tube of smaller than conventional inner diameter, which is readily capable of being coiled upon a reel of relatively compact size, may be used with the inlet nozzle of the oral evacuator without reducing the static suction pressure below a satisfactory, relatively high operative level at the nozzle. This results in the fluid and entrained debris which is drawn into the nozzle traveling at a very high speed, such as approximately 190 per second. A further distinct advantage arises from this high speed in that it insures not only continual but practically instantaneous cleansing of the tube when the system is operating, thus eliminating any possibility of accumulation of foul matter upon the inner walls of the tube 26.

Notwithstanding, such relatively high static suction at the nozzle 30, when complete or even full blocking of inlet to the nozzle occurs, such as by engaging the inner surface of the cheek or tongue of a patient with the tip of the nozzle, no serious possibility of injury or discomfort to the patient occurs because of the instantaneous operation of the relief valve in the evacuator handpiece 28 which reduces the static suction pressure to a safe level. The relief valve is described in detail hereinafter. However, it is to be noted that it is located only a few inches from the nozzle inlet tip and is preferably regulated to function upon an increase of static suction caused when the nozzle 30 is placed against mouth tissue. The nozzle tip may be easily removed from its contact with the flesh, at the resulting reduced suction level, whereby normal suction then is restored and the relief valve instantly closes.

SOLIDS COLLECTOR Details of the solids collector are best shown in FIG. 7. The entire assembly of the collector unit 16 includes a cuplike receptacle or enclosure 76 which, for serviceability and utility may be formed from stainless steel. The rim 78 preferably is received within a groove-like flanged perimeter 8-0 of the top cover 82. A suitable gasket 83 is mounted within the groove of perimeter 80 for liquid-tight engagement by the rim 78 of enclosure 76. Disengageable positioning means are described below.

Preferably, the top cover 82 is securely supported by a suitable bracket 84 which is shown in exemplary manner in FIGS. l, 3 and 4. Projecting upward from said bracket is a metal tube 86. Aixed to the upper end thereof is one end of a rigid metal U-shaped gooseneck 88, the opposite end thereof being rigidly connected to a preferably metal, or at least a still, discharge tube which terminates at its, lower end a short distance from the bottom of the cuplike enclosure 76. The top cover 8-2 also is provided with an opening defined by an annular flange 92 through which the discharge tube 90 extends and to which it is rigidly connected, whereby the tube 86 and gooseneck 88, in conjunction with discharge tube 90, form the support for the top cover 82.

Also connected to the top cover 82 is an inlet distributor tube 94 which preferably is rigid, such as a suitable metal tube. The inlet tube 94 extends through another opening in the top cover 82 defined by the annular flange 96, to which the upper end of tube 94 is fixed. The upper end of tube 94 preferably projects above flange 96 for connection thereto of one end of inlet litt-ing 52, the opposite end thereof being connected to inlet conduit 18 which extends from the passages in the reel assembly and described hereinabove. Inlet fitting 52 also is provided with a transversely-extending, smaller inlet member 98, to which the discharge end of conduit 48 is connected for the introduction of cooling water for the pump into the solids collector 16.

From FIG. 7, it will be seen that the lower, discharge end of the inlet distributor tube 94 is tapered. The shape thereof, for example, `may be formed -by cutting a metal tube on the bias, preferably at an acute angle to the longitudinal axis of the tube, whereby -a diagonal shape of discharge end 100 is formed. Such shape is highly beneficial for purposes of evenly distributing the incoming fluid which is to be evacuated to the separator 32, from which the fluid portion thereof is discharged to a sewer. It is desirable that relatively even discharge of the incoming liquid and entrained solid particles occur throughout substantially the entire vertical length of the enclosure 76, particularly for purposes of subjecting said liquid and particles to the action of the elongated filter or strainer 102.

The strainer 102 preferably is formed lfrom suitably sized wire gauze or mesh. The opposite ends thereof respectively are fitted with an upper rigid metal collar 104, and a bottom imperforate cap 106 which also may be formed from metal. The opposite ends of the cylindrical strainer 102 are connected, such as by solder, respectively to the collar 104 and cap 106. A coiled metal spring 108 also is disposed on the interior of the strainer to lend rigidity thereto and also to exert limited pressure in axial direction respectively against the collar 104 and cap 106,

thereby maintaining the strainer 102 in stable, cylindrical shape so as to withstand suction forces imposed thereon by the flow of liquid through the strainer into the lower end of discharge tube 90.

The collar -104 has a central opening defined by a Short cylindrical guide and positioning flange 109 which extends around the discharge tube 90. Though the fit between the flange 109 and tube 90 preferably is relatively close, when the enclosure 76 is removed, the strainer assembly readily -falls by gravity from the tube 90. To

maintain the strainer assembly in operative position rela-4 tive to tube 90, a short coiled compression spring 110 is connected 'at its upper end to an appropriate projection on the bottom cap 106 and the Ilower end of the spring engages the bottom of the enclosure 76 to place the spring under light compression and thereby operatively positions the strainer assembly or unit relative to the discharge tube 90 within the enclosure 76.

The details of the apparatus within and adjacent the solids collector 16, as described hereinabove, is of such nature that relatively even collection of solid particles will occur upon the exterior of strainer 102, substantially for the full length thereof, primarily because of the relatively even distribution of incoming liquid and entrained particles, in a vertical direction, which is caused by the shape at the diagonal discharge end 100 of the inlet tube 94. Under conditions where the suction apparatus of the entire system is fairly actively used in the course of a day, best operation thereof will dictate that the Solids collector be emptied and cleaned about once each day.

The continua-l flow of liquid through the solids collector, especially in view of the constant introduction of water through the inlet member 98 whenever the vacuum system is used, will insure a minimum accumulation of soluble waste matter in the collector because the same will constantly be dissolved and passed from the solids co1- lector to the pump 10 and from there to the sewer after passing through the separator 32. Solid matter will accumulate either in the bottom of the cup-like enclosure 76 or upon the exterior of the strainer 102.

At any given time when cleaning of the solids collector occurs, it will be found that the cup-like enclosure 76 will be only partially filled with Iliquid and any entrained material. Upon disconnecting the enclosure 76 from the top cover 82, the strainer -assembly will fall automatically by gravity from the discharge tube 90 and remain in the enclosure 76. By placing the enclosure and strainer in a sink, for example, and flushing it by tap water from -a faucet, most if not all of the accumulated debris will be removed and substantially no foul odor or messy contents will exist with respect to the removed apparatus. An ordinary tooth brush is use-ful to clean the strainer, if necessary. Accumulated solid material may be dumped from the enclosure 76 and the strainer assembly and enclosure then may quickly be replaced in their operative position with respect to discharge tube 90 and top cover 82.

Relative to maintaining the cup-like enclosure 76 in operative position against the top cover 82, simple clamping means of the type shown in exemplary manner in FIGS. 3 and 4 may be employed in which it will be seen that a short arm 112 is pivotally mounted at one end for movement -about the metal tube 86. The outer end of arm 112 carries a threaded clamping screw 114 having a suitable knob on the lower end thereof by which the screw may be threaded upward into engagement with the bottom of the enclosure 76 to maintain it securely against the top cover 82. By lowering the screw 114 from engagement with the enclosure 76 and swinging the arm 112 to one side, said enclosure and the strainer mechanism readily may be removed for emptying and cleansing. Equivalent clamping means, such as a pivoted bail, not shown, may be used in lieu of the means specically described and illustrated.

8 ASPIRTING HANDPIECE AND NOZZLE The vacuum produced by the system comprising the present invention is partly utilized to evacuate the portable cuspidor 38 and the saliva ejector `42, as described above. Under normal circumstances in modern dental operatories however, the lmajor use of the vacuum system at present normally is in connection with operating the so-called high volume oral evacuator comprising the handpiece 28 and nozzle 30. These are shown in their overall relationship with the entire system, diagrammatically, in FIG. l. For details of such evacuator however, attention is directed to FIGS. 8-10, which details now will be described.

The handpiece 28 essentially comprises a shelllike housing or handle 116 which, in addition to providing a handle engaged by the operator such as a dental assistant or dentist, also contains a flow-control valve 118 and an automatically operable relief valve 120. The tubular housing 116 may be formed from suitable material Such as metal, for example, and the forward end or nose member 122, may be formed from synthetic resin or the like, if desired. The rearward end of member 122 is connected to the forward end of housing 116 as shown in FIGS. 8 and 9. Fixedly mounted within and spaced slightly inward from the rear end of housing 116 is -an automatically operable relief va-lve comprising a disc-like ported valve member 124 which is provided on its rearward end with a coupling extension 126, the same having a central passage 127 therethrough. The Ivalve member 124 also preferably has a guide sleeve 128 surrounding the inner end of said central passage 127 which receives the rearward end of an interior inlet tube 130 and supports the same coaxially within housing 116.

The coupling extension 126 primarily comprises coupling means over which one end of the suction tube 26 extends, the same being clamped thereon by a threaded clamping collar 132, the inner end of which threadably engages an annular enlargement 134 on the coupling eX- tension 126. The relief valve comprises a circular disc having a forwardly extending guide sleeve 136 thereon which is readily slidable upon the guide sleeve 128 which also comprises an inlet tube. The valve disc is apertured also to receive sleeve 128 and the rearward face thereof nearest the valve member 124 has a flat, annular gasket-like member 138 fixed to the valve member 120 for direct engagement with the inner surface of the valve member 124. A compression spring 140 of suitable strength extends between the inner face of member 122 and the inner surface of valve member 120 as shown in FIG. 9.

Suction nozzle 30 is preferably a metal tube of suitable diameter, the diameter thereof illustrated in FIG. 9 closely approaching actual size. The outer, inlet end 142 thereof preferably is on the bias as shown in said figure. The opposite end 144 of said nozzle is tted into the outer vend of circular passage 146 which extends axially entirely through the forward end member 122, the rear end of said passage terminating in closely spaced relationship to the forward end of guide sleeve 128. The end 144 of the nozzle is firmly but releasably held within the forward end of passage 146 by appropriate means such as an O-ring 148 shown in FIG. 9. If desired, collar or flange 150 may be fixed to the outer end of member 122 to minimize Wear upon the tip of said member which might result from insertion of the nozzle within the passage 146.

The forward end member 122 preferably supports the flow-control valve 118. Said valve comprises a movable valve member 152 which is best shown in plan view in FIG. 10. Preferably, the valve member is of uniform thickness such as shown in FIG. 9 and is somewhat of a so-called butterfly shape, having an arcuate inner surface 154. Member 152 oscillates about a pivot pin 156 which is parallel to but offset laterally from the passage 146. Preferably, the member 122 is fitted at its rearward end into the forward end of the sleeve-like housing 116 and is connected thereto preferably by complementary threaded means 158. The pivot pin 156 is inserted within a suitable longitudinal hole extending inward from the rearward end face of member 122, the outer end of pin 156 preferably being enlarged and threaded for engagement with complementary threads in member 122, thereby retaining the pin in operative position and also permitting ready removal thereof.

Valve member 152 is accommodated within a recess 160 which is transverse to the axis of handpiece 28 and is complementary in width to the valve member and the innermost wall 162 thereof is generally as illustrated in FIG. lO. The opposite ends of said Wall subtend a substantial obtuse angle and respectively comprise stop surfaces engageable by the opposite sides of the valve member 152 when moving the same between open and closed positions relative to the central passage 146 in lmember 122.

Valve member 152 is provided with a valve opening 164 preferably of the same diameter as the portion of the passage 146 which is intersected by the recess 160. When the valve member 152 is in the position shown in full lines in FIG. l0, the flow-control valve will be open due to the registry of opening 164 with the passage 146. When, however, the valve member 152 is moved to the closed position shown in dotted lines in FIG. 10, the valve opening 164 will be out of registry with the passage 146 and the valve will be closed.

To facilitate releasably maintaining the valve member 152 in its closed and open positions or any intermediate position, relatively simple friction means are utilized which are shown in FIGS. 9 and 10. The exemplary fraction means thus shown comprise a pair of similar friction buttons 166, having reduced inner ends thereon and formed by molding or otherwise from synthetic resin for example. A short compression spring 168 of appropriate strength extends between the buttons 156 and urges them apart equally in opposite directions respectively for slidable, frictional engagement with the parallel side walls of the recess 160. Various other types of appropriate position-maintaining means may be used in lieu of the buttons 156, if desired.

In operation, suction within the evacuator handpiece 128 and nozzle 30 is induced by the negative pressure present in the suction tube 26, which negative pressure is imposed upon the nozzle by means of the passage 146 and sleeve 128 which extend between said nozzle and the coupling extension 126 to which the tube 26 is connected. The static suction present in the evacuator 28 'and the volumes of fluid which it is capable of passing at predetermined rates are ofthe order as set forth hereinabove. Particularly the volume of fluid capable of being passed through the evacuator 28 may be at least partially controlled depending upon the degree to which the flow-control valve 118 is opened. For example, if it is only partially opened, it is obvious that less volume `will be passed through the evacuator 28 than when the valve is fully opened.

If, during the operation of the evacuator unit 28, the inlet end 142 of the nozzle should more or less squarely contact a tissue surface on the interior of the oral cavity in which the evacuator is being operated, either partial or complete stoppage of the passage of iiuid through the nozzle 30 and evacuator handpiece will occur. Such a situation is 'capable of producing harmful results upon A"the patient such as by raising blisters, bruising the tissue, or otherwise. In certain existing types of vacuum systems used by the dental profession at present, automatically operable relief valves are located at the pump or suction blower. Under such circumstances, it is obvious that a certain time delay will occur before the relief valve opens,

`due particularly to the length of the suction hose and the various passages and tubes between the suction nozzle and the pump. Y

The present invention obviates such difficulty and minimizes the possibility of danger occurring by providing directly in the handle or housing 116 of the evacuator 28, the automatically operable relief valve 120 described hereinabove. The valve member 124 of said relief valve is provided with a circular arrangement of inlet ports 170, the size and arrangement thereof being shown best in FIG. l0. In normal operation, the ports 170 are closed by the gasket member 138 upon the movable valve member 120. The yielda'ble spring 140 normally maintains the valve closed.

The strength of the spring 140 is carefully calibrated so that upon stoppage of passage through the nozzle 30 or substantial reduction of the passage of fluid therethrough occurring at any instant, the suction normally imposed upon the interior of the evacuator 28 by the negative pressure in suction tube 26 will cause such negative pressure to draw atmospheric air through the annular passage 172 adjacent the rear end of the housing 116 for direct communication with the inlet ports 170.

The application of such air against the relief valve 120 forces it instantly to open position and the resulting introduction of atmospheric air therethrough to the interior of the housing 116 immediately reduces the suction upon the nozzle 30 to a safe level so that there is little if any possibility of any substantial injury or even noticeable discomfort experienced by the patient. The tip of the nozzle is always open to atmosphere so that, normally, the static suction pressure at the very tip is substantially atmospheric. However, when the tip engages tissue so as to substantially block inlet of air therethrough, the safety relief valve 120 will open due to the increase in static suction pressure thus created across the valve face. The ingress of air results in the static suction pressure not exceeding approximately 8 of mercury which causes no injury and permits purging of the line 26 and also permits removal of the tip of the nozzle from the tissue without discomfort. Immediately upon the outer end of the nozzle 142 being removed from engagement with the tissues which resulted in the initial opening of the safety relief valve 120, the spring 140 will instantly force the valve 120 closed and full suction immediately will be restored to the nozzle 30.

The arrangement of the structure described above also provides another advantageous result in that, by providing the emergency, automatic relief valve 120 within the evacuator handpiece housing 116 per se, rather than near the pump, results in the in rush of atmospheric air to the suction tube 26 effecting a purging or cleansing of said tube by drawing any fluid matter present therein, at the time the stoppage of the nozzle 30 occurred, to the pump 10 or at least to some location in the tube 26 between the evacuator 28 and the pump, whereby, immediately upon restoration of normal suction through the nozzle 30, continued movement of the partially removed uid in the tube 26 will occur.

ELECTRIC CIRCUIT One suitable and convenient electric circuit operable to furnish current to the various elements requiring the same as illustrated, for example, in exemplary manner in FIG. 1, is shown diagrammatically in the lower portion of said figure. Referring to said illustration, the current supply line to the circuit is represented by the conductors 174 and 176. A customary fuse or circuit breaker 178 is included in one of said conductor lines. Included preferably in this same line is a manually operable control switch 180, the operating element of whichis conveniently located upon the cabinet for the system shown in FIGS. 2 and 2a. Said cabinet also is provided with a suitable single receptacle 182 of adequate size or a plurality of individual receptacles to receive the evaculator 28 and cuspidor 38. Positioned adjacent each of the receptacles is the actuating member for additional control switches 186 and 188 so as to cause said switches to be activated when either the evacuator or cuspidor are removed from the receptacles therefor.

In the circuit diagram of FIG. 1, it will be seen that the switches 186 and 188 are substantially in parallel and serve to complete the circuit for the operation of the motor 12 of the pump regardless of whether the oral evacuator or cuspidor, or both, are withdrawn from the receptacle for use with a patient. The circuit also may include, if desired, a suitable time delay device 190 which includes an additional switch 192. The operation of said time delay device and the switch therein is such that when the circuit to the motor 12 is established, the switch 192 of the time delay device 190 also will close.

Following the completion of use of either the cuspidor or the oral evacuator, and replacing the same within the receptacle therefor, the switch 186 or 188 associated therewith will `be opened for purposes of disrupting the circuit to the motor 12 but, as will be seen diagrammatically in FIG. 1, the switch 192 will remain closed for a predetermined period of time, such as five or ten seconds, as controlled by the setting desired for the time delay device, and thereby cause the pump motor 12 to continue to run for that period of time to insure complete purging of all suction lines in use in regard to the operation of any of the suction instruments and devices before the operation of the pump 10 stops.

I claim:

1. An oral vacuum system comprising in combination:

(a) a liquid ring pump having a motor to drive the same at a predetermined speed and having inlet and outlet ports connected to the pump chamber,

(b) discharge conduit means extending at one end from said exit port of said pump chamber and the other end being interconnectable to sewer means,

(c) flexible inlet conduit means interconnected at its discharge end to the inlet port of said pump chamber, and

(d) an aspirating unit comprising:

(1) a valve housing having inlet and discharge means on the opposite ends thereof, said discharge means being connected to said inlet conduit means,

(2) an inlet nozzle connected to the inlet end of said housing and insertable in the oral cavity of a patient to aspirate spray and liquid and any entrained solids therefrom,

(3) a manually operable valve in said valve housing normally operable to control the llow of liquid to said inlet nozzle, and

(4) an automatically operable relief valve interconnected to said valve housing and operable upon -ow through said inlet nozzle being impeded sufficiently to open said valve and thereby permit the inlet of air to said flexible inlet conduit means to permit purging said system and prevent injury to the patient, said valve housing having an internal inlet tube extending axially therein in communication with said inlet nozzle and relief valve having a spring of predetermined force surrounding said tube and operable against a valve member normally to maintain said valve closed, said spring being compressible by suction operable against said valve member when ow through said inlet tube is impeded as aforesaid, said valve member has a radial ange and is centrally apertured to receive and move axially along said internal inlet tube, said valve housing having inlet port means adjacent said inlet end thereof arranged at least partially around the axis of said internal inlet tube and positioned to be closed by said radial flange of said valve member when said valve member is urged into closed position by said spring.

2. The vacuum system according to claim 1 in which said inlet port means comprises a series of similar substantially evenly spaced ports arranged circumferentially around said axis of said internal inlet tube.

3. An oral vacuum system comprising in combination:

(a) a liquid ring pump having a motor to drive the same at a predetermined speed and also having inlet and outlet ports connected to the pump chamber,

(b) discharge conduit means extending at one end from said exit port of said pump chamber and the other end being interconnectable to sewer means,

(c) iiexible inlet conduit means interconnected at itS discharge end to the inlet port of said pump chamber,

(d) aspirating means connected to said inlet conduit means,

(e) a collector unit comprising a collector casing having inlet and discharge means connected to the upper portion thereof,

(f) means connecting said inlet and discharge means in said collector unit between said aspirating means and said pump,

(g) water inlet means connectable at one end to a source of flushing fluid and connected at the other end to said inlet means of said collector unit and operable to pass water through said collector unit to dissolve and entrain soluble material passing from said aspirating means to said pump and thereby free said collector unit from such soluble material and also provide said fluid as a liquid ring in said pump to cause it to function normally, and

(h) means in said collector unit operable to prevent the passage of solid material larger than a predetermined size to the discharge means of said collector unit.

4. The vacuum system according to claim 3 in which said discharge means for said collector unit extends toward the bottom of said collector casing and said aforementioned means to prevent passage of solid material comprising screen means arranged relative to said discharge means in said collector unit to prevent the passage thereto of said solid material in excess of a predetermined size, and means on said inlet means of said collector unit operable to distribute incoming iluid and entrained debris relatively evenly to the surface of said screen means.

5. The vacuum system according to claim 4 in which said discharge means for said collector unit comprises a tube extending downward from the top and the inlet end of said tube being spaced a limited distance above the bottom of said collector casing, said screen means surrounding said discharge tube to restrict the size of material entering the same, said inlet means of said collector unit comprising a tube extending downward from the top of said casing, and said means on said inlet means to distribute incoming uid comprising arranging the extremity of said inlet tube diagonally within a plane disposed at an acute angle to the axis of said tube, the apex of said angle being at the lower end of said inlet tube.

6. The vacuum system according to claim 4 in which said collector casing comprises a cup-like receptacle detachably connectable at its upper end to a top and said inlet and discharge means comprising tubes extending substantially perpendicularly through said top, said screen means also surrounding said discharge tube and said screen means and receptacle being interengageable to maintain said screen means in operative position relative to said discharge tube and said screen means also being capable of freely dropping from said discharge tube for disposition in said receptacle when the latter is removed from said top to service said collector unit. Y

7. The vacuum system according to claim 6 in which said screen means is a sleeve having end members lconnected to the opposite ends thereof and inner means resistant to inward radial movement and operable to prevent collapsing of said screen sleeve, and said collector casing also having means engaging the lower end of said Screen means to hold the same in operative position with 1 3 said discharge tube as long as said receptacle remains connected to said top for said casing.

8. The oral vacuum system according to claim 3 further including:

(a) an electric circuit for said motor,

(b) means to support said aspirating means when not in use,

(c) switch means in said motor circuit operable incident to removing said aspirating means from the support therefor to activate said motor circuit and deactivate said circuit upon restoring said aspirating means to said support, and E (d) time delay means in said motor circuit operable upon restoration of said aspirating means to said support to delay the disruption of said motor circuit for a predetermined period of time sufficient to permit said pump to purge the inlet line thereto from said aspirating means.

9. An oral vacuum system comprising in combination:

(a) an evacuator nozzle insertable into the oral cavity to remove debris from dental cutting and the like,

(b) a power operated liquid ring pump of high suction capacity and having a pump chamber operable to directly receive lluid and air from said nozzle and discharge it to sewer means,

(c) a flexible inlet tube connected at its inlet end to,

said nozzle to receive liuid and air therefrom, said tube having an interior diameter no greater than substantially .375 in diameter,

(d) a reel of limited diameter and a width complementary to the outer diameter of said inlet tube mounted for rotation about its axis and arranged to receive said tube to be coiled upon and uncoiled from said reel and having means to connect one end of said tube thereto,

(e) means connected to said reel and operable to rotate the same in one direction to coil said tube within a single plane upon said reel and permit rotation of said reel in the opposite direction when uncoiling said tube therefrom,

(f) conduit means extending between said reel and pump chamber,

(g) a rotary connector between said flexible tube and reel and connected to said conduit to permit transmittal of uid material through said tube and conduit for entry into said pump chamber, and

(h) discharge conduit means connected at one end to said pump chamber and the other end being connectable to a sewer, said pump having a normal operating capacity in relation to the inner diameter of said exible tube to evacuate fluid and air at the rate of not substantially in excess of 6 c.f.m. and develop a status suction at the pump of not substantially less than 10 inches of mercury, whereby the speed of such Huid and air through said flexible tube is at least 100'/sec. and said speed insures substantially continuous complete evacuation from said tube when said system is operating, and

(i) collector means for solid material of predetermined maximum size arranged between said reel and said pump, said collector means having water inlet means connectable to a source of water, and means to control the delivery of a continuous predetermined amount of water to said collector means for delivery to said pump to cool the same and maintain a liquid ring in said pump while the system is operating.

References Cited UNITED STATES PATENTS 2,784,717 3/1957 Thompson 128--276 2,885,782 5/1959 Groves 32-33 3,108,738 10/1963 Luhmann 230--79 3,112,061 11/1963 Breer l28-278 X 3,208,145 9/1965 Turner 32-33 3,280,458 10/1966 Deeley 32-22 LOUIS G. MANCENE, Primary Examiner C. R. WENTZEL, Assistant Examiner

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