referring first to fig1 , there is shown a system schematic diagram of a portion of a typical milking system , generally at reference number 100 . a vacuum pump 102 is connected to a vacuum regulator 104 and to a vacuum header or distribution manifold 106 . vacuum pump 102 may be of any type well known to those of skill in the art of vacuum systems , such as model no . m7 . 5 , manufactured by masport , inc ., the exact specification of vacuum pump 102 forming no part of the instant invention . vacuum regulator 104 is shown schematically as a bypass regulator , such as model no . 350 , manufactured by western dairy research , inc ., but any other form of vacuum regulator such as an in - line regulator or a variable - speed vacuum pump drive system may also be used . a pulsator 108 is connected to header 106 by pulsation line 110 . main vacuum line 112 connects header 106 to a milk receiver 116 via a moisture trap 114 . milk receiver 116 is shown connected to a milk line 118 which is , in turn connected to milking machine 120 shown connected to the teats of an animal 122 . milk pump 124 pumps milk from milk receiver 116 to a holding tank , not shown , for further processing . a typical milking system such as that shown in fig1 may have hundreds of feet of vacuum lines and many interconnections . consequently , there are numerous points where vacuum leakage may occur . while vacuum regulator 104 normally keeps the vacuum level within predetermined limits , no vacuum monitoring tracks either the instantaneous or long - term performance . developing leaks or degradation of vacuum pump 102 or vacuum regulator 104 , therefore , can not be detected until the milking performance is badly degraded . the method of the present invention provides comprehensive vacuum system monitoring to detect the earliest stages of system performance degradation , whether from developing leaks or from degradation of a system component . the vacuum system capacity is monitored and evaluated in a number of independent ways . referring now to fig2 , there is shown a simplified version of the milking system of fig1 , having vacuum monitoring devices in accordance with the present invention . vacuum pump 102 , vacuum regulator 104 , header 106 , pulsator 108 and milk receiver 116 are still present in the same arrangement as described hereinabove . a vacuum sensor 202 is shown disposed in vacuum line 214 adjacent vacuum pump 102 but before the point vacuum regulator 104 is connected . another vacuum sensor 204 is placed leader 204 , typically relatively close to regulator 104 . additional vacuum sensors 206 , 208 are disposed in vacuum line 118 . still another vacuum sensor 210 is placed in pulsation line 110 . vacuum sensors are off - the - shelf commercial vacuum sensors adapted to produce an electrical output representative of a vacuum level present thereat . a model no . px241 vacuum sensor , manufactured by omega or equivalent , has been found satisfactory for the application . although not specifically shown in fig2 , vacuum sensors 202 , 204 , 206 , 208 , 210 are each electrically connected to a monitor 300 ( fig3 ) as described in detail hereinbelow . an air admission device 212 is attached to vacuum line 214 , also adjacent vacuum pump 102 and before the point of attachment of vacuum regulator 104 . air admission device 212 is designed to open vacuum line 214 to a predetermined amount of air and may be a solenoid - operated valve with a calibrated orifice , not shown . the orifice may have either a fixed or variable diameter , depending upon the actuation method used . any other device through which a predetermined amount of air may be admitted to vacuum line 214 may be utilized . air admission device 212 is also operatively connected to controller 300 as described hereinbelow . it will be recognized that while five vacuum sensors have been shown for purposes of disclosure , other numbers of sensors , even as few as one sensor , may be required depending upon the size and complexity of the vacuum system installed in a particular milking parlor . in fact , no sensor is required when the system operates on the basis of mass flow . also , while the vacuum system of a milking parlor has been chosen to describe the inventive methods , these methods are also applicable to vacuum systems in other environments . referring now to fig3 , there is shown a schematic diagram of a monitoring and control system suitable for practicing the method of the invention , generally at reference number 300 . a monitor / controller 302 , hereinafter controller , is schematically shown . as will be recognized by those of skill in the art , controller 302 may be implemented in many configurations and the invention is not considered limited to the exact controller 302 shown for purposes of disclosure . controller 302 accepts electrical output signals from vacuum sensors 202 , 204 , 206 , 208 , 210 ( fig2 ) and using signal conditioning and / or conversion circuitry , not shown , converts incoming electrical signals to actual vacuum readings . these readings may be selectively provided on a display 304 . a keypad 306 may be used to monitor individual ones of sensors 202 , 204 , 206 , 208 , 210 and / or a flow meter , not shown , placed , for example , between vacuum regulator 104 and vacuum pump 102 . key pad 304 or programming interface 310 may be used to preload acceptable ranges for each of vacuum sensors 202 , 204 , 206 , 208 , 210 typically when the vacuum system is first installed . a control output 308 is provided to electrically actuate air intake device 212 ( fig2 ) upon command from controller 302 . it will be recognized that while electrical actuation of air intake device 212 has been chosen for purposes of disclosure , mechanical , hydraulic , or pneumatic action could also be used to accomplish the actuation . it is anticipated that controller 302 is a microprocessor - based controller utilizing non - volatile memory to store instructions , fixed data , and accumulated data from the vacuum sensors 202 , 204 , 206 , 208 , 210 . controller 302 implements several different monitoring functions . in a first monitoring method , air intake device 212 is periodically activated . the effect of this activation on the vacuum level at sensor 204 or another of vacuum sensors 206 , 208 , 210 ( i . e ., in the controlled section of the vacuum system ) is observed . if measured vacuum at sensor 204 , etc . does not drop below a predetermined value , the capacity of the system is deemed to be acceptable . in other words , vacuum pump 102 and vacuum regulator 104 are probably both operating properly and it is likely that no significant leaks occur in the vacuum system . the acceptable vacuum level is predetermined , typically at the time the monitored system 200 is installed . if , however , the actuation of air intake device 212 causes vacuum loss at sensor 204 , etc ., an alarm is generated . this alarm may be a visual indicator 312 or an internal , audible alarm , not shown . in addition , an alarm signal line 314 may be used to actuate a remote alarm . another measurement of vacuum system status is performed by controller 302 as the vacuum system is first started . the time necessary for the vacuum level to rise from approximately 10 % to approximately 90 % of the nominal vacuum level can be measured . the measurement of this slew rate is another way of evaluating the overall health and integrity of the vacuum system . as described , an unacceptable slew rate at vacuum system startup may trigger an alarm . another way in which the inventive system may monitor vacuum system health is by developing statistics regarding normal vacuum excursions and establishing a baseline of normal vacuum system behavior and , optionally , evaluating the statistics to determine trends . controller 302 may then monitor vacuum level excursions on an ongoing basis and evaluate excursions to determine the fall in an acceptable range of values . still another way the method of the invention uses to evaluate vacuum system health is to monitor total mass flow rate , which should remain within a predetermined set of limits . mass flow rate is easily monitored by readily available commercial products . a typical mass flow measurement consists of a rotary vane placed in the air ( or vacuum ) stream to be measured . rotation of the vane is easily monitored and correlated to the mass flow of the air stream causing the van rotation . another method of evaluating vacuum system performance is to compare the vacuum level at or near the vacuum pump 102 ( e . g ., at vacuum sensor 202 ) to the vacuum level on the regulated side of the system ( e . g ., at one of vacuum sensors 204 , 208 , 208 , 210 ). that ratio should remain relatively constant if the capacity of vacuum pump 102 has not been reduced or if the vacuum system 200 otherwise has not been degraded . another method of assessing the performance of the vacuum system 200 is to compare the vacuum level of remote sections of the system ( e . g ., at vacuum sensors 206 , 208 , 210 ) to the area near the vacuum regulator ( e . g ., vacuum sensor 204 ). again , that ratio should remain within specific limits if the vacuum system 200 is operating at a normal , acceptable capacity ( i . e ., vacuum system 200 is not degraded ). since other modifications are changes varied to fit particular operating conditions and environments or designs will be apparent to those skilled in the art , the invention is not considered limited to the examples chosen for purposes of disclosure , and covers changes and modifications which do not constitute departures from the true scope of this invention . having thus described the invention , what is desired to be protected by letters patents is presented in the subsequently appended claims .
there is provided a method for monitoring a vacuum system such as that used in a dairy milking system . several independent measurements are made whereby a long term degradation of the vacuum pump or other component in the vacuum system may be identified before system performance drops below acceptable limits . baseline data generated when the vacuum system is known to be in good working order . the baseline data is used to compare operation of the vacuum system . an alarm signal or other indication may be generated to alert an operator that vacuum system performance has degraded beyond an acceptable limit . such predictive failure techniques allow maintenance to be performed on the vacuum system long before performance degrades to a point where a system becomes inoperative .