Abstract:
A fluid flow indicator including a disk and spring assembly positioned within a fluid conduit whereby the pulsing force a fluid input biases the disk and spring against an electrical contact thereby completing an electrical circuit and illuminating a visual indicator.

Description:
PRIORITY APPLICATION 
     This application claims the benefit of prior application Ser. No. 60/373,729, filed Apr. 18, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to fluid flow indicators and specifically to an indicator that provides a visual indication of a pulsating fluid flow. 
     It is common to include lubrication devices in the design of industrial machinery. Specifically, lubricant may be provided to bearings, journals, chains, sprockets and other machine components. The lubrication devices may include pumps that meter lubricant to the machine at a predetermined level or at predetermined time intervals. The lubricant is typically stored in a lubricant supply source, such as a tank and then delivered by a conduit to a pump. The amount of lubricant in the tank or other supply source may be monitored by a sight gage, float gage, or similar device. A second conduit directs the lubricant from the pump either to the machine or to a lubricant manifold where it may be subsequently sent to multiple locations on the machine. 
     In most applications if the supply tank is full, it is assumed that lubricant is being delivered to the machine component. However, if the supply conduit breaks or the pump malfunctions, there is typically no indication of lack of lubricant flow until a machine component fails. There is a need for a device that monitors fluid flow downstream of the lubricant pump and provides a confirming signal that fluid is flowing from the pump outlet. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a device for monitoring fluid flow from a pressurized fluid output, such as the output from a pump or metering device. The fluid flow indictor activates an indicator, such as a light emitting diode, in response to a predetermined increase in the pressure of the fluid flowing through a conduit. Specifically, a pulse is generated by an increase in fluid pressure across a specified plane within a cavity or chamber, followed by a pressure drop across the plane, and then equalization of the pressure across the plane. This pulse translates into instantaneous force acting on the plane. A disk is placed in the plane causing the pulse to be amplified. The disk is then unidirectionally linearly dampened with a conical spring, resulting in displacement of the disk along a linear axis from an initial position to a second position. 
     The invention utilizes a power supply, such as one or more button cell batteries, and a visual indicator, such as a light-emitting diode (LED), in a closed loop circuit with the spring and the disk. The spring and disk assembly functions as switch, closing the circuit when the fluid pressure reaches a predetermined level. This results in illumination of the indicator. Thus, as pressurized fluid flows through the conduit, the device allows for a continuous visual monitoring of the fluid flow in a display on the LED. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the fluid flow indicator of the present invention; 
     FIG. 2 is an exploded perspective view of the fluid flow indicator; 
     FIG. 3 is a side elevational view of the indicator assembly installed in a typical fluid flow circuit. 
     FIG. 4 is a cut-away side elevational view of the indicator with no fluid flowing; and 
     FIG. 5 is a cut-away side elevational view of the indicator during fluid flow. 
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, the fluid flow sensor assembly of the present invention is designated generally by the reference numeral  10 . A housing  11  has a longitudinal through bore  12  extending from the housing  11  top surface  13  to its bottom surface  15 . A pair of counter bores  23  is formed inwardly from both the top surface  13  and the bottom surface  15 . The counter bore  23  at the top surface is preferably provided at its inlet end with threads  17  engageable with a threaded pipe nipple  20 . The counter bore  23  at the lower end of the bore  12  is provided with threads  18  engageable with an outlet pipe nipple  21 . (See FIGS. 4 and 5.) The nipples  20  and  21  are threaded to a conduit  14  located in a fluid flow line emanating from a tank of fluid to be sensed by the sensor assembly  10  (not shown). 
     An elongated milled slot  26  is formed in the front face  16  of the housing  11 . Two large counter-bores  30  and  31  are sized to each hold a pair of batteries  19   a  and  19   b , and are further configured to define the slot  26 . The respective axes of the counter-bores  30 ,  31  preferably lie substantially perpendicular to the axis of the longitudinal bore  12 . 
     Referring next to FIG. 2, a smaller diameter counter-bore  34  is formed parallel to and between the aforementioned larger counter-bores  30 ,  31  and is arranged to retain a light-emitting diode (LED)  36 . Within the uppermost larger counter-bore  30 , there is a centrally located small diameter bore  38  (see FIG.  4 ). The small diameter counter-bore  38  extends diametrically across the longitudinal bore  12  to intersect with the shoulder  24  formed at the junction of counter bore  23  and the bore  12 . The bore  38  is arranged to receive a wire lead  40  emanating from the battery  19   a  and having a flat contact portion  40   a  resting on the shoulder  24  and lying transversely across the diameter of the counter bore portion  23  of the bore  12 . The housing  11  is preferably fabricated from acetyl or other non-conducting material. 
     A contact disk  42  is secured to a conical spring  44  and the assembly is inserted into the upper opening or fluid inlet end of the bore  12  in the housing  11 . The disk  42  and spring  44  are preferably fabricated from brass and stainless steel, respectively. The electrically conductive wire battery lead  40  provides a stationary contact for electrically mating with the contact disk  42  through spring  44  during fluid flow pressing against the disk  42 . The lead  40  is inserted within the bore  38  in the upper battery pocket  30 , extending across the counter bore  23  to rest on the shoulder  24 . The end of the push wire lead  40  is bent over allowing a battery  19   a  to be inserted into the battery pocket  30 . The light emitting diode  36  has two leads  46 ,  47 . Lead  46  is known as the anode and lead  47  is known as the cathode. The anode lead  46  is trimmed to a length of {fraction (21/32)} inches. The cathode lead  47  is trimmed to a length of {fraction (5/16)} inches and then bent at substantially right angle as shown in FIGS. 1,  4  and  5 . The LED  36  is inserted into the LED counter bore  38 . In a preferred embodiment ,the LED  36  is a high efficiency green at  45  degrees cone angle LED that is daylight visible. 
     The batteries  19   a  and  19   b  supply power to the indicator assembly  10 . In the preferred embodiment, the batteries are conventional silver oxide button cell batteries having a predetermined power rating. Each battery  19   a ,  19   b  is placed into its respective battery pocket, or counterbore  30  and  31 . The counter-bores  30  and  31  are each dimensionally contoured to accommodate a respective button cell battery  19   a  and  19   b . An electrically conductive battery jumper tab  22  retains the batteries  19   a ,  19   b . The tab  22  is placed over the batteries  19   a ,  19   b  and is retained by a pair of drive mounting studs  25  (See FIG.  2 ). The studs  25  engage with a friction fit into openings  27  formed in the housing  11 . It should be noted that the tab  22  has a central opening  29  formed therein. The LED  36  passes through the central opening  29  when the tab or jumper  22  is installed. 
     Finally, a conventional, epoxy-based potting compound  49  is mixed and poured into the milled slot  26  and over the above-described components. Care must be taken to insure that the potting compound  49  does not coat the LED  36  or overflow from the slot  26 . The potting compound  49  cures in approximately 12 hours, during which time the indicator assembly  10  should remain on a flat surface. 
     As best seen in FIGS. 4 and 5, the helical spring  44 , push wire lead  40 , contact disk  42 , LED  36 , batteries  19   a ,  19   b  and jumper tab  22  form an electrical circuit. The batteries  19   a ,  19   b  are connected in series by the jumper tab  22 . The push wire lead  40  connects the upper battery  19   a  to one end of the helical spring  44 . The helical spring  44 , coupled to the contact disk  42  forms a switch in conjunction with lead wire  46  of the LED  36 . The other lead wire  47  (cathode), emanating from LED  36 , is connected to the other battery  19   b . When the disk  42  contacts the anode lead  46  of the LED  36 , the electrical circuit is closed thereby illuminating the LED  36 . When the disk  42  retracts under the force of spring  44 , the circuit is opened and the LED  36  is no longer illuminated. 
     Again referring to FIGS. 4 and 5, the indicator assembly  10  is installed between a fluid inlet  48  and a fluid outlet  50 . Fluid flows under a predetermined pressure into the indicator  10  from a source, such as a PURGEX® metering pump, manufactured by OIL-RITE® CORPORATION of Manitowoc, Wis. As the fluid contacts the disk  42 , the fluid pressure overcomes the resistance of the spring  44  attached to the disk  42 . The disk  42  is displaced from its initial position to a second position where it contacts the lead wire  46  as shown in FIG. 5, thereby completing the electrical circuit. When the electrical circuit is closed, the LED  36  illuminates. As the pressure from the pulse of the fluid diminishes, the spring force overcomes the fluid force and the disk  14  moves back to its initial position as shown in FIG.  4 . When the metering pump expels the next fluid pulse, the electrical circuit will be completed again and the LED  36  will be illuminated. The illuminated LED  36  provides a visual indication that fluid is flowing through the indicator assembly  10 . 
     The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention.