Patent Publication Number: US-2012034116-A1

Title: Compressor

Description:
INTRODUCTION 
     This invention relates to a compressor and, more particularly, to a diaphragm compressor used generally with a diesel heater and which compressor is used to provide the necessary air under pressure in order to draw fuel into an atomizing fuel nozzle. 
     BACKGROUND OF THE INVENTION 
     Powered heaters which use diesel fuel can take many different forms. The present heater with which the compressor is used is a powered heater with an atomizing type nozzle. The use of air under pressure when introduced to the nozzle creates a negative pressure or suction which draws fuel into the nozzle which fuel is then mixed with the air and forms a cone shaped spray emanating from the nozzle with fine particles of fuel. The spray is ignited by a flame rod which is electronically activated. 
     The compressor is important in such a vaporizing type burner. Any variation of the pressure from the compressor affects the spray pattern and, hence, the combustion characteristics of the burner which, in turn, will adversely will affect BTU output and the emission output from the burner or any heater within which it is positioned. The compressor must not only maintain appropriate characteristics throughout a range of operation but it also must be robust for long life. Its operating characteristics must remain consistent over the life of the compressor and this is particularly so for military operations which use such a burner. 
     Previously, compressors have been used with various problems arising. One problem is that the valves on such compressors are usually made from a petroleum based material. Upon exposure to diesel laden fumes from the heater, the valves are adversely affected which lowers the life of the valves and, during the period before failure of the valves and adversely affects the operating profile of the compressor. A further problem with existing compressors is that the motors which power the piston and diaphragm are susceptible to overheating due to long hours of compressor use. The overheating is passed to the valve material which adversely affects the valve operation and may cause premature failure. Yet a further motor problem is that the compressor starts and stops many thousands of times with the heater being turned off and on to effect the heating of coolant used both for space heating and for heating potable water for use in showers and the like. If the motor does not have sufficient robustness, flat spots will occur between the brushes and the windings which will prevent the compressor from being operated. Yet a further problem lies in the interface between the valves and the compressor head where the valves alternatively open and close. It is important that this interface maintain integrity in both the open and closed positions to properly maintain the pressure from the compressor when the valves are open and to allow the pressure to be reduced when the valve is closed. Previously, due to heat on the compressor head, the interface could deform thus adversely affecting the seal between the valve and the seat. Adversely affecting this seat adversely affects the characteristics of air emanating from the compressor. Yet a further problem with existing compressors is that they are specifically designed for maintaining specific pressure. If a different pressure is required, the compressor must be replaced or substantially modified. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, there is provided a compressor used for supplying air to a nozzle, said compressor comprising a motor with an extending shaft to power said compressor, an eccentric crank connected to said shaft, a crank rod connected to said eccentric crank, a counterbalance connected to said eccentric crank and used to offset the force generated by the rotation of said crank rod and said eccentric crank, a body portion within which said crank rod moves and which includes a body head, a valve head portion housing inlet and outlet openings with flapper valves allowing the opening and closing of said inlet and outlet openings, a spacer portion having inlet and outlet passageways allowing egress and ingress of air moving through said inlet and outlet openings, a diaphragm between said body head and spacer portions which diaphragm is moved upwardly and downwardly by said crank rod, a seal between said valve head and spacer portions and first and second generally flat flappers opening and closing said inlet and outlet passageways, one of said flappers being connected to said valve head portion and the other of said flappers being connected to said spacer portion. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Specific embodiments of the invention will now be described, by way of example only, with the use of drawings in which: 
         FIG. 1  is a diagrammatic isometric view of the compressor and motor according to the invention in its closed position and further illustrating the inlet port with air filter fitting attached to the head; 
         FIGS. 2A and 2B  are diagrammatic isometric and side views of the compressor of  FIG. 1  particularly illustrating the counterweight connected to the motor shaft and the plug closing the opening in the body of the compressor; 
         FIG. 3  is a diagrammatic isometric view particularly illustrating the head of the compressor and the components within in head; 
         FIG. 4  is a diagrammatic isometric view of the compressor particularly illustrating the flapper valve of the compressor used for the outlet; 
         FIG. 5  is a diagrammatic cutaway view of the compressor illustrating its principal components as well as the crank rod connected to the eccentric; and 
         FIG. 6  is a diagrammatic schematic view of the operating components of a diesel fueled air aspirated burner which includes the compressor according to the invention. 
     
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENT 
     Referring now to the drawings, a burner is generally illustrated at  100  in  FIG. 6 . The components that are included in such a burner  100  include a nozzle  101  to disperse the air and fuel, a fuel solenoid  102  used to prevent fuel flow back from the nozzle  101 , a fuel regulator  103  known as a zero pressure regulator, a fuel pump  104  used to pump fuel from the fuel supply (not illustrated) to the zero pressure regulator  103  and thence to the nozzle  101  and a fuel filter  110  to filter the diesel fuel coming from the fuel supply (not illustrated). A combustion fan  111  draws ambient air into the burner  100  and provides this air into the combustion chamber shown generally at  112 . The air provided by the combustion fan  111  is intended to create a forced air flow through the combustion chamber  112  so as to provide optimal combustion for the air and fuel. An igniter  113  is provided to provide an infrared glow so as to ignite the fuel-air mixture emanating from nozzle  101 . 
     A compressor  120  is operably mounted so as to provide a constant air supply to the nozzle  101  at a specific and predetermined pressure and flow rate. A filter  121  filters the ambient air before it enters the compressor  120 . 
     Referring now to the compressor generally illustrated at  120  in  FIG. 1 , a motor  122  is connected to the body portion  123  of compressor  120  with screws or bolts  124  ( FIG. 2A ). Motor  122  has a shaft  130  ( FIG. 2B ) protruding from one end. The shaft  130  extends through a bearing  131  ( FIG. 5 ) mounted within a crank rod  132  which reciprocates when the motor  122  is operating. The crank rod  132  has a piston head  133  with a rubber or synthetic flexible diaphragm  134  connected thereto by way of a circular keeper  140  and bolt  141  extending through the keeper  140  and into the piston head  133  to retain the diaphragm  134 . 
     Inlet and outlet passageways  142 ,  143 , respectively, extend through the valve head portion  144 , thence through a spacer  150  and into the cavity  151  formed between the spacer  150  and the diaphragm  134 . A pair of generally flat flapper valves  152 ,  153  made from thin spring steel are provided so as to allow air egress and air ingress to the cavity  151 . The use of spring steel for the flapper valves  152 ,  153  allows for a long lasting and diesel resistant operation. Flapper valve  152  is connected to the head portion  144  by a screw or bolt (not illustrated) so as to move in a cantilever type motion and opens and closes the outlet passageway  143 . Flapper valve  153  is connected to the spacer portion  150  in the same manner and opens and closes the inlet passageway  142 . O-rings  154  are provided within machined grooves in the spacer  150  and serve to reduce the noise of the flapper valves  152 ,  153  as they open and close and also to lend additional effectiveness to the sealing ability of the compressor  120  when the respective flapper valves  152 ,  153  are in their closed positions. 
     Spacer  150  is sandwiched upon assembly between valve head portion  144  and body head portion  160 . Four bolts  161  ( FIG. 1 ) extend from the head  144 , through spacer  150  and diaphragm  134  into the body head portion  160  of body  123  to tightly seal the three components. An o-ring  162  is positioned within a machined groove in spacer  150  and surrounds the outlet passageway  143  in spacer  150  to ensure all air emanating from the outlet passageway  143  in spacer  150  exhausts through outlet passageway  143  and to ensure sealing integrity. 
     The body  123  has a circular opening  163  machined in one side ( FIG. 3 ) so as to allow access to the interior of the body  123  for assembly and servicing operations. A removable rubber plug  164  ( FIG. 1 ) is used to close the opening  163  after assembly to prevent the ingress of contamination though the opening  163 . To service or inspect the components within the body  124 , the plug  164  is manually removed. 
     A counterweight  170  ( FIG. 3 ) is connected to the shaft  171  of the eccentric  172  ( FIG. 5 ). The counterweight  170  operates to offset the force created by the rotation of the eccentric  172 . 
     Air filter  121  ( FIG. 3 ) is provided to filter the air entering into the inlet passageway  142  of compressor  120 . 
     Fins  173  are provided on the outside of the valve head  144  ( FIG. 1 ) to allow better dissipation of the heat buildup which takes place during compression. 
     Operation 
     In operation, the power switch (not illustrated) is turned on to provide power to the heater  100  ( FIG. 1 ). The igniter  113  will begin to glow and the combustion fan  111  will remain in the off condition. For a HURRICANE (Trademark) heater manufactured by International Thermal Research Ltd. of Richmond, British Columbia, Canada, the igniter  113  will remain on for a period of approximately ten (10) seconds to allow it to reach ignition temperature. 
     The air compressor  120 , fuel pump  104 , fuel solenoid  102  and combustion fan  111  will then be turned on. 
     The motor  122  of compressor  120  will rotate and the shaft  130  of the motor  122  will rotate the eccentric  172  mounted to the shaft  130  ( FIGS. 1 and 5 ). The shaft  171  of eccentric  172  will provide the reciprocating motion to the crank rod  132  and the crank rod  132  will rotate at the same rpm as the motor  120 . Upwardly and downwardly movement is therefore provided to diaphragm  134 . As the diaphragm  134  moves downwardly as viewed in  FIG. 5 , flapper  153  will open as air is drawn into the inlet air passageway  142 , through the opening created by the now open flapper valve  153  and into cavity  151  in the spacer  150 . 
     When the diaphragm  134  reaches its most downwardly position and crank rod  132  begins to move upwardly as seen in  FIG. 5 , flapper  153  will close under the positive pressure in cavity  151  and flapper  152  in outlet passageway  143  will open. Air will therefore exhaust through outlet passageway  143  under a predetermined pressure and at a predetermined flow rate according to the size of the cavity  151 , the speed of the motor  122  and the sizes of the inlet and outlet passageways  142 ,  143 . 
     The air under pressure will leave the outlet passageway  143  and enter the nozzle  101  ( FIG. 6 ). The solenoid  102  will be in the open position to allow fuel to pass from the fuel regulator  103  to the nozzle  101 . The compressed air is guided over the tip of the nozzle  101  where a negative pressure is created. The negative pressure will draw fuel from the fuel regulator  103  to the nozzle  101 . The nozzle  101  creates a fine cone pattern spray which is ignited by the igniter  113 . 
     Fuel pump  104  pumps fuel to the fuel regulator  103  and a fuel filter  110  is provided to filter the fuel entering into fuel pump  104  from a fuel supply (not illustrated). 
     The combustion fan  111  draws in outside ambient air which creates a forced air flow through the combustion chamber  112  and to exhaust the combustion gasses through an exhaust system (not illustrated). 
     When the operation of the burner  100  is terminated, the solenoid  102  is closed to prevent fuel from being drawn from the nozzle  101 . This allows a cleaner ignition of the fuel when the burner  100  commences operation. 
     Many modifications will readily occur to those skilled in the art. For example, the inlet passageway  142  in the valve head  144  ( FIG. 5 ) may be fitted with an air bleeder hole  174  which extends from the outside of the valve head  144  and through the space  180  ( FIG. 5 ) between the air inlet cavity  181  and the air outlet cavity  182  as is illustrated by the broken lines in  FIG. 5 . A set screw (not illustrated) would be inserted into the air bleeder hole  174  and would allow adjustment of air passing between the inlet air chamber  181  and the outlet air chamber  182 . This would allow for the pressure provided to the nozzle  101  by the compressor  120  to be adjusted depending upon the fuel combustion characteristics desired by the specific nozzle  101  that might be used in the heater. 
     While the compressor  101  is made from aluminum to prevent rusting and to provide lightened weight, it is contemplated that other suitable materials might also be used. For example, stainless steel could be used or the entire compressor  101  could have the components molded in an appropriate synthetic plastic. The use of molded materials could also enhance the sound deadening qualities of the compressor  101  and would reduce costs for large quantities of production. 
     It is important for the flapper valves  152 ,  153  to be of the appropriate thickness for the characteristics of the compressor  101 . If the thickness of the flapper valves  152 ,  153  is too great, the cantilever action will be restricted and thereby reduce the air traveling through the inlet and outlet chambers which, in turn, will reduce the pressure emanating from the compressor  101 . A thickness for the flapper valves  152 ,  153  which is too small will result in inadequate sealing strength when the flapper valves are closed or it may result in damage to the flapper valves since they would be too think to accept a certain amount of punishment during operation. 
     Many further modifications will readily occur to those skilled in the art to which the invention relates and the specific embodiments herein described should be taken as illustrative of the invention only and not as limiting its scope as defined in accordance with the accompanying claims.