Pumps – Condition responsive control of pump drive motor – With condition responsive control of pump fluid valve
Reexamination Certificate
2001-04-06
2003-03-25
Freay, Charles G. (Department: 3746)
Pumps
Condition responsive control of pump drive motor
With condition responsive control of pump fluid valve
C417S044100, C417S279000, C137S907000, C119S014010
Reexamination Certificate
active
06537033
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
REFERENCE TO A “MICROFICHE APPENDIX” (SEE 37 CFR 1.96)
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an open loop control apparatus for a vacuum controlled system for providing vacuum stability within a predetermine range of vacuum levels and more particularly relates to a vacuum relief regulator for use in a vacuum controlled milking system wherein the vacuum relief regulator includes a transducer for producing output signal which is applied to a control device for producing a control signal for controlling speed of a variable speed motor which drives a vacuum pump at various speeds to maintain enough vacuum reserve to allow efficient vacuum relief operation thereby maintaining the vacuum level of the vacuum system within a predetermined range of vacuum levels.
2. Description of the Prior Art
Vacuumed controlled milking systems are well known in the prior art. Typical vacuum controlled milking are disclosed in U.S. Pat. Nos. 5,141,403; 5,284,180 and 4,011,838.
U.S. Pat. Nos. 5,141,403 and 5,284,180 disclose a low-energy-consuming apparatus and method for controlling vacuum levels in milking machines. The milking machine includes a high vacuum reserve including an adjustable speed drive motor driving a vacuum pump, a low-vacuum reserve which operates the milking appears, and a dual vacuum controller. The dual vacuum controller senses vacuum disturbances in the low-vacuum end and adjusts the flow rate of air from the low-vacuum end to the high vacuum reserve. The high vacuum reserve portion of the apparatus includes a vacuum transducer which senses the vacuum in the high volume reserve which varies in response to the vacuum level in the low-vacuum-reserve, to control the speed of the adjustable speed motor thereby providing a controlled vacuum level with minimum pressure variance and energy savings due to a reduction in demand.
U.S. Pat. No. 4,011,838 discloses a milking machine system which includes a flow rate sensing device, a timing device and a system control means for varying the character of the working and massage vacuums during the milking process. The system uses a conventional vacuum pump and vacuum regulator.
U.S. Pat. Nos. 4,955,408; 4,944,249; 4,273,154; 3,938,547; 3,482,593 and 2,667,856 disclose various vacuum regulator devices which utilize a diaphragm and air ports for controlling vacuum levels in a typical milking system.
U.S. Pat. Nos. 4,191,090; 4,166,476; 3,982,553; 3,583,779 and 3,527,241 disclose various vacuum-pressure regulating devices and pressure regulating devices which utilize a diaphragm for controlling vacuum or pressure levels in a vacuum or pressure system requiring controlled vacuums or pressures. U.S. Pat. No. 4,191,090 discloses the use of an elecro-mechanical transducer located in a vacuum line and separate from a vacuum regulator.
None of the vacuum regulators or systems using vacuum regulators anticipate, disclose, teach or suggest affixing a transducer, such as for example a linear stroke transducer, which produces an output voltage which varies linearly as a function of the displacement of the diaphragm within or inside of the mechanical vacuum controller, to sense the movement of the diaphragm.
In addition, two references which disclose vacuum controlled milking systems having variable or adjustable drive motors for driving a vacuum pump at controlled speeds are: (1)
Adjustable Speed Drive for Diary Vacuum Pumps
, Pages 1-6 Published by, the EPRI Industrial & Agriculture Business Unit—No. 2, 1996 (the “EPRI Reference”); and (2)
Smart Technology for Vacuum Pump Control Saves Money and Reduces Noise
; Sales Brochure, Sides 1 and 2, Dltech, Inc., 1997 (the “DLtech Reference”). The EPRI Reference appears to disclose the same information subject of U.S. Pat. Nos. 5,141,403 and 5,285,180 discussed above.
The Dltech Reference discloses use of a sensing system which functions as a vacuum control in a milking system by controlling the speed of a variable speed frequency motor which drives a vacuum pump. The vacuum control senses vacuum levels in the vacuum system and in components of the milking system, excluding the vacuum regulator. The vacuum control increases or decreases the speed of the variable speed motor as required to increase or decrease the vacuum level. The sensing system detects the attaching of milking units to the milking system and causes the motor speed to increase increasing the vacuum level to match airflow. The sensing system detects completion of attaching of milking units to the milking system and reduces the speed of the motor decreasing the vacuum level.
FIG. 1
, labeled Prior Art, depicts a known vacuum controlled system using a milk claw. In
FIG. 1
, a vacuum source shown by dashed box
20
produces a controlled vacuum by means of a motor
22
driving a vacuum pump
24
at a constant speed. The vacuum is maintained by state-of-the art vacuum regulator
28
which admits or bleeds air at atmospheric pressure into the vacuum system to correct and/or maintain the vacuum level. The vacuum regulator
28
is typically a vacuum controller which is used to mechanically regulate the vacuum levels, an example of which is the vacuum controller disclosed in U.S. Pat. No. 3,938,547.
The vacuum source
20
is used to provide a regulated vacuum to a milking system shown generally as
30
. A typical milking system includes a vacuum reservoir
32
, milking claws
34
, having pulse controlled inflations
38
, pulsator
40
, appropriate vacuum control lines, milking lines and a collection vessel such as a milk jar
44
. Such vacuum controlled milking systems are well known in the art and need not be described in detail herein.
FIG. 2
labeled Prior Art illustrates a known prior art apparatus for use as the vacuum source in lieu of the vacuum source
20
shown in FIG.
1
. This vacuum source is likewise illustrated by dashed box
20
in FIG.
2
. In
FIG. 2
, a vacuum pump
50
is driven by a three phase AC variable speed motor
52
, the rotational speed of which is controlled by a variable frequency drive
56
. In the prior art apparatus, a control device
60
is responsive to a vacuum transducer
64
which detects the absolute vacuum level and sends a signal representative of the absolute vacuum level to the control device
60
which is responsive thereto to vary the speed of the motor. A vacuum controller
68
is used to mechanically regulate the vacuum level.
The present invention relates to an improved vacuum controller for regulating the vacuum level and to a transducer which is adapted to be operatively connected to the vacuum controller for providing an output signal which represents an instantaneous position of the diaphragm, a valve and valve opening in the vacuum controller. The output signal is used to generate or produce, as the case may be, a control signal to control the speed of the AC variable speed motor driving the vacuum pump. In the Prior Art apparatus as illustrated in
FIG. 2
, the signal may be used to control the speed of the variable drive motor.
SUMMARY OF THE PRESENT INVENTION
The present invention discloses and teaches a new, novel and unique open loop control apparatus for a vacuum controlled system for providing vacuum stability within a predetermined range of vacuum levels. The control apparatus includes a vacuum regulator having a diaphragm including a valve member having a valve opening or input port which changes position as a function of the vacuum level within the vacuum system for controllably admitting or bleeding air into the vacuum system to adjust the vacuum level within the system. A transducer is operatively coupled to the diaphragm for producing an output signal which represents the instantaneous position of any one of the diaphragm, valve member, the valve opening or input port. A control device having a pair of inputs and an output, has applied to one of the pair of inputs a set point signal representing a programmed vacuum level for the system. Applied to the o
Brazil Lionel H.
Jackson Donald
Meaney, Jr. Daniel J.
Western Dairies Incorporation
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