Abstract:
A nozzle for a mist lubricator system has an emitter head located in a tubular housing. The emitter head has tapered passageways terminating at an end from which lubricant drops are directed to a target to be lubricated. The emitter head can be incorporated in lubricator systems of various types, including those utilizing a cycling feed metering system. A nozzle constructed in accordance with the present invention can be used in reduced airflow systems and exhibits substantially lessened lubricant loss during low and no airflow periods.

Description:
The present invention relates to a new and improved nozzle for a lubrication apparatus and to an emitter element therefor. 
     BACKGROUND OF THE INVENTION 
     The provision of lubrication to a particular location in an apparatus, such as a knitting machine, loom, or the like, is often required. Such lubrication is often provided by a lubricant mist directed towards the targeted area, but the stream is often difficult to direct with accuracy. The lubricant provided by a mist system also often coagulates into drops of various sizes. The presence of a spray of drops having a range of sizes impedes control over the amount of lubricant dispersed and its accurate delivery. Other systems dispense a pulsed series of lubricant “slugs” or drops of varying size. 
     In U.S. Pat. No. 5,639,028 to the present inventor and assignee, an improved nozzle apparatus for use in lubricant mist systems is disclosed. The nozzle set forth therein generates a lubricant stream of small, consistently sized drops that can be accurately directed to a part to be lubricated. Dripping from the nozzle is substantially eliminated, and the nozzle can be used over a wide range of air pressures, including reduced airflow lubrication systems of the aerosol type. 
     Mist generator systems in which the nozzle of the &#39;028 Patent are employed may have a plurality of nozzles connected to a single generator, with the number of nozzles approaching 30 in number. With increasing energy costs, the cost of providing compressed air to such a plurality of nozzles can be a considerable operational expense. While limiting the amount of air passing through the nozzle would appear to be an obvious solution to such increasing costs, insufficient extraction of lubricant from the aerosol can occur as the air pressure is lowered, leading to excessive lubricant loss and thus mitigating the value of the nozzle apparatus. 
     The cycling of air through a plurality of nozzles can also conserve the amount of air required. U.S. Pat. No. 6,571,918 discloses a lubricant distributor that meters lubricant into precise individual volume amounts and directs individual volumes to a distribution and spray system. Such cycling systems can lessen air costs, but can lead to lubricant accumulation and run-off through a nozzle when the airflow is either off or below the designed operational threshold pressure for the nozzle. Such run-off results in lubricant loss as well as insufficient lubrication for the targeted area. 
     It is accordingly a purpose of the present invention to provide a new and improved nozzle assembly particularly adapted for use in reduced airflow situations in oil mist lubrication systems of the type disclosed in the &#39;028 Patent. 
     A further purpose of the present invention is to provide a nozzle of the general type disclosed in the &#39;028 Patent in which lubricant loss is substantially lessened, if not eliminated, during low airflow and no airflow periods. 
     Yet a further purpose of the present invention is to provide an emitter head for mist lubrication nozzles, such as those of the type set forth in the &#39;028 Patent, that allows the nozzle to meet the aforementioned purposes and goals. 
     Yet a further purpose of the present invention is to provide a nozzle and emitter head which are of simple and economical construction, and which can be used in connection with existing lubricator equipment, including those of the type utilizing a cycling feed-type metering system, such as set forth in U.S. Pat. No. 6,571,918. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In accordance with the above and other objects and purposes, a nozzle in accordance with the present invention has a tubular housing having an emitter head that converts a sheet-like flow of lubricant into a series of lubricant drops that are directed to a lubricant target by an accompanying carrier gas flow. The emitter head has one or more passageways along which the lubricant and carrier gas flow. The passageways are of a tapered configuration, having a wide width entrance area to effect efficient collection of the lubricant and carrier gas, and an exitway of narrowed size, allowing the lubricant to be delivered to a needle-like end at the head where the drops are formed and from which the drops are propelled to the target by the carrier gas in the form of a series of consistently-sized drops. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A fuller understanding of the present invention will be obtained upon consideration of the following detailed description of a preferred, but nonetheless illustrative embodiment thereof, when review in conjunction with the annexed drawings, wherein: 
         FIG. 1  is a perspective view of a lubrication nozzle incorporating the present invention, an inner core having the inventive emitter head being shown in phantom; 
         FIG. 2  is an elevation view of the inner core of  FIG. 1 ; 
         FIG. 3A  is a section view taken along line A-A in  FIG. 2 ; 
         FIG. 3B  is an elevation view taken from the left end of  FIG. 2 ; 
         FIG. 4  is a detail view of the emitter head of the invention; and 
         FIG. 5  is a schematic presentation of a mist lubrication system in which the present invention can be used. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With initial reference to  FIG. 5 , in accordance with the teachings of U.S. Pat. No. 5,639,028, the contents of which are incorporated herein by reference, nozzle  10  of the present invention may comprise a part of an oil mist lubrication system. Such a system typically includes an oil mist source  12  connected to the nozzle  10  by means of a flexible mist transporting tube  14 . The nozzle  10  is mounted in an appropriate support structure, and is positioned to direct its oil droplet output towards an intended portion of a machine to be lubricated, as illustrated by the mechanism  16 . 
     As seen in  FIG. 1 , the nozzle  10  may comprise an outer tubular sleeve or housing  18 , typically formed of a plastic, with a core element  24 , typically of brass, mounted in the housing. The housing may be joined at a first end to a coupling  20 , which joins the nozzle to a pipe or hose from the oil mist source  12 . The oil mist or aerosol enters the nozzle through coupling  20 , the nozzle extracting the lubricant from the aerosol and converting it into a series of lubricant drops that form on the needle-like end  22  of nozzle core  24  to be carried by the carrier gas exiting from the nozzle to the intended target. 
     As set forth in the &#39;028 Patent, nozzle core  24  functions as an element for separating suspended oil from the carrier gas and for collecting the separated oil and channeling the oil into the interior of the carrier gas stream exiting from the nozzle. With further reference to  FIG. 2 , the core includes helical portion  26  joined through neck portion  30  to emitter head  28 , which terminates in needle point  22 . Helical portion  26  may be formed as a series of thread turns about stem  32 . The threads of helical portion  26  engage the inner wall of the housing, as seen in  FIG. 1 , forming a helical passageway between the core and the inner surface of the housing wall. The helical portion serves as a means for separating oil particles in the supplied oil mist stream from the carrier gas flow. The coalesced droplets collect and flow along the housing wall inner surface to the emitter head  28 . 
     The emitter head  28 , further detailed in  FIG. 4 , may have a main, generally cylindrical body portion  34  and a generally conical exit portion  36  terminating in needle  22 . The main body portion may also be tapered at its leading end  38  to form a smoother transition from neck  30 . The outer surface  40  of the main body is in contact with the inner surface of housing  18 . One or more grooves  42  are formed in the head, forming lubricant/gas passageways between the head and the housing. Each passageway has a relatively wide entranceway  44 , tapering into central/exit portion  46 . In a nozzle with a main body portion diameter of 0.064 inch and a neck diameter of 0.030 inch the central/exit groove portion may have a width of 0.015 inch. 
     As seen in  FIG. 4 , the central/exit groove portion  46  may extend along the main axis of the emitter head and nozzle core, which is normally co-axial with the main longitudinal axis of the nozzle. 
     The entranceway  44  is offset from the central/exit portion  46  of the passageway, with an asymmetrical inwardly tapering cross section, tapering inward from a widened mouth to the central/exit portion of the passageway by way of helical wall surface  48 . The helical wall surface preferably has the same rotational sense as the helical portion  26 . The bottom of the passageway may be at or slightly below the surface of the neck  30 , as seen in  FIG. 3A , further dropping or slanting downward towards the needle tip  22  as it passes through exit area  46  of the emitter head, as seen in  FIG. 3B . The maximum width and cross-sectional area of the entranceway may be 2 to 3 times the width and cross-sectional area of the central/exit portion. 
     The passageway grooves may be three in number, located equidistantly about the periphery of the head, with each of the entranceway helical walls being of the same sense as the helix of helical portion  26 . The grooves  42 , by virtue of their tapering construction, accelerate the gas flow passing through the nozzle, thus providing for more efficient flow of the lubricant sheet along the grooves surfaces and entrainment and transport of the lubricant droplets forming on the needle tip  22  to the intended target. In addition, the helical wall of the entranceway, having the same sense of the helical portion  26 , minimizes momentum loss of the gas carrier as it passes into the head, thus improving overall nozzle efficiency. 
     As the oil reaches the head assembly, it passes from the housing wall onto the facing surface of the main body portion and spreads over the surface of the passageway grooves, continuing to be driven forward along the passageways by the carrier gas. As the passageways exit onto the tapered exit portion  36  of the head, the oil film travels to its needle point  22 . It collects there, forming a droplet of growing diameter, until the force exerted upon the droplet by the exiting carrier gas is sufficient to remove it from the point, carrying the droplet with the carrier gas flow to the target to be lubricated. 
     The passageway grooves have an uneven cross-sectional area, the cross-section of the groove lessening towards the exit edge  50  of the housing  18 . This causes any lubricant that remains in that portion of the groove when gas flow is interrupted to be drawn back towards the wider entranceway portion  44  of the groove by surface tension. Thus, nozzle dripping is minimized. 
     The head construction depicted in  FIG. 4  can be machined with a CNC lathe milling head. A construction in which the entranceway is more offset with respect to the central/exit portion of the groove, as generally depicted in  FIG. 1  with a pair of opposed helical wall portions, requires more complicated milling procedures, but may have a marginally higher efficiency. 
     While the embodiments presented in the Figures depicts the emitter head as part of a unitary nozzle core construction including a helical portion  26 , it is to be appreciated that other embodiments and adaptations of the invention are possible without departing from the intended scope of the invention, including utilizing the emitter head in a lubrication system in which a discrete element for coagulating lubricant from a mist into a liquid flow is not present, or is separate from an emitter head element. Thus, the present invention may be used in a variety of lubrication systems, including those in which lubricant is distributed in a liquid form using a metering device of U.S. Pat. No. 6,571,918, as well as the constructions depicted in FIGS. 5-7 of U.S. Pat. No. 5,639,028.