U.S. patent application number 11/746164 was filed with the patent office on 2008-11-13 for sweetening and cleaning system for lapping machines.
This patent application is currently assigned to DANIEL L. BOWERS CO., INC.. Invention is credited to Keith Alan Urban.
Application Number | 20080280537 11/746164 |
Document ID | / |
Family ID | 39969971 |
Filed Date | 2008-11-13 |
United States Patent
Application |
20080280537 |
Kind Code |
A1 |
Urban; Keith Alan |
November 13, 2008 |
SWEETENING AND CLEANING SYSTEM FOR LAPPING MACHINES
Abstract
A sweetening and cleaning system that is used with one or more
lapping machines to sweeten a lapping compound in a sweetening
mode, and to clean parts of the system itself and parts of the one
or more lapping machines with a cleaning compound in a cleaning
mode. The system includes a virgin receptacle for holding the
lapping compound, a cleaning receptacle for holding the cleaning
compound, a waste receptacle for holding waste, and at least one
pump.
Inventors: |
Urban; Keith Alan; (Sylvan
Lake, MI) |
Correspondence
Address: |
JAMES D. STEVENS;REISING, ETHINGTON, BARNES, KISSELLE, P.C.
P.O. BOX 4390
TROY
MI
48099
US
|
Assignee: |
DANIEL L. BOWERS CO., INC.
Rochester Hills
MI
|
Family ID: |
39969971 |
Appl. No.: |
11/746164 |
Filed: |
May 9, 2007 |
Current U.S.
Class: |
451/36 ;
451/444 |
Current CPC
Class: |
B08B 9/00 20130101; B24B
37/00 20130101; B24B 55/00 20130101 |
Class at
Publication: |
451/36 ;
451/444 |
International
Class: |
B24B 1/00 20060101
B24B001/00 |
Claims
1. A sweetening and cleaning system for one or more lapping
machine(s), comprising: a virgin receptacle holding a lapping
compound and being piped to the lapping machine(s); a cleaning
receptacle holding a cleaning compound and being piped to the
lapping machine(s); a waste receptacle holding waste that is piped
from the lapping machine(s); and a first pump that pumps the
lapping compound from said virgin receptacle to the lapping
machine(s) during part of a sweetening mode of the sweetening and
cleaning system, and that pumps the cleaning compound from said
cleaning receptacle to the lapping machine(s) during part of a
cleaning mode of the sweetening and cleaning system.
2. A sweetening and cleaning system as defined in claim 1, further
comprising a second pump that pumps waste from the lapping
machine(s) to said waste receptacle during part of both the
sweetening and cleaning modes of the sweetening and cleaning
system.
3. A sweetening and cleaning system as defined in claim 2, further
comprising: a first level sensor located in a machine reservoir of
the lapping machine(s) that is adjustable so that said first level
sensor is set to determine the amount of waste that is pumped out
of the machine reservoir by said second pump during the sweetening
mode; and a second level sensor located in the machine reservoir
that is set to determine the amount of lapping compound that is
pumped into the machine reservoir by said first pump during the
sweetening mode.
4. A sweetening and cleaning system as defined in claim 2, further
comprising: a first skid constructed to carry said virgin
receptacle, said cleaning receptacle, said waste receptacle, and
said first pump; and a second skid constructed to carry said second
pump.
5. A sweetening and cleaning system as defined in claim 1, wherein
said first pump is a single peristaltic pump that is piped to both
said virgin receptacle and said cleaning receptacle.
6. A sweetening and cleaning system as defined in claim 5, further
comprising a three-way valve having a first inlet port connected to
said virgin receptacle, a second inlet port connected to said
cleaning receptacle, and an outlet port connected to said
peristaltic pump, said first inlet port being selectively open
during part of the sweetening mode, and said second inlet port
being selectively open during part of the cleaning mode.
7. A sweetening and cleaning system as defined in claim 1, further
comprising: a first two-way valve having an inlet port connected to
the lapping machine(s) and an outlet port connected to said
cleaning receptacle, said ports being selectively open during part
of the cleaning mode; and a second two-way valve having an inlet
port connected to the lapping machine(s) and an outlet port
connected to said waste receptacle, said ports being selectively
open during part of both the sweetening and cleaning modes.
8. A sweetening and cleaning system as defined in claim 7, further
comprising: a third two-way valve having an inlet port connected to
said first pump and an outlet port connected to the lapping
machine(s), said ports being selectively open during part of both
the sweetening and cleaning modes; and a fourth two-way valve
having an inlet port connected to said first pump and an outlet
port connected to said cleaning receptacle, said ports being
selectively open during part of the cleaning mode.
9. A sweetening and cleaning system as defined in claim 1, further
comprising: a first filter located downstream the lapping
machine(s) and upstream said cleaning receptacle that filters
cleaning compound during part of the cleaning mode; and a second
filter located downstream a machine reservoir of the lapping
machine(s) and upstream a machine cell of the lapping
machine(s).
10. A sweetening and cleaning system as defined in claim 1, further
comprising a programmable logic controller (PLC) that communicates
with the lapping machine(s), reads inputs from various components
of the sweetening and cleaning system, sends outputs to control the
various components, and employs a human-machine interface
(HMI).
11. A sweetening and cleaning system as defined in claim 1, further
comprising a plurality of pipes connecting said virgin receptacle,
said cleaning receptacle, said waste receptacle, and the lapping
machine(s), wherein said pipes share a generally uniform diameter
throughout their length and change directions through about
45.degree. laterals and sweeping radiuses that is a multiple of 6
times said pipe diameters.
12. A sweetening and cleaning system as defined in claim 1, wherein
said virgin receptacle is piped to a three-way valve, said cleaning
receptacle is piped to said three-way valve, said three-way valve
is piped to said first pump, and said first pump is piped to the
lapping machine(s).
13. A method of sweetening and cleaning one or more lapping
machine(s), comprising: providing a virgin receptacle that holds a
lapping compound, a cleaning receptacle that holds a cleaning
compound, and a waste receptacle that holds waste; in a sweetening
mode, removing waste out of a machine reservoir of the lapping
machine(s) and pumping the waste directly to said waste receptacle;
in the sweetening mode, adding the lapping compound to the machine
reservoir; in a cleaning mode, purging the lapping machine(s) by
removing waste out of the machine reservoir and pumping the waste
to said waste receptacle, and adding the cleaning compound to the
machine reservoir; and in the cleaning mode, priming the lapping
machine(s) by adding the lapping compound to the machine
reservoir.
14. A method of sweetening and cleaning as defined in claim 13,
wherein the purging further comprises recirculating the cleaning
compound from said cleaning receptacle to a bypass loop that
bypasses the lapping machine(s) and back to said cleaning
receptacle for a predetermined amount of time to clean said bypass
loop, and concurrently recirculating the cleaning compound through
the lapping machine(s).
15. A method of sweetening and cleaning as defined in claim 13,
wherein the purging further comprises emptying the cleaning
compound out of the machine reservoir.
16. A method of sweetening and cleaning as defined in claim 13,
further comprising providing a first pump that pumps the lapping
compound out of said virgin receptacle and pumps the cleaning
compound out of said cleaning receptacle, and a second pump that
pumps waste from the machine reservoir to said waste
receptacle.
17. A method of sweetening and cleaning as defined in claim 13,
further comprising, in the sweetening mode, removing the waste out
of the machine reservoir for a predetermined amount of time and
adding the lapping compound to the machine reservoir for a
predetermined amount of time.
18. A method of sweetening and cleaning as defined in claim 13,
wherein the purging further comprises removing waste out of the
machine reservoir to a set low level in the machine reservoir, and
adding the cleaning compound to the machine reservoir to a set
second level in the machine reservoir.
19. A method of sweetening and cleaning as defined in claim 18,
wherein the purging further comprises continuing to remove waste
out of the machine reservoir after the set low level for a
predetermined amount of time.
20. A method of sweetening and cleaning as defined in claim 13,
wherein the sweetening mode is automatically initiated after a
predetermined event, and the cleaning mode is automatically
initiated after a predetermined event.
21. A sweetening and cleaning system for one or more lapping
machine(s), comprising: a virgin receptacle holding a lapping
compound and being piped to the lapping machine(s); a cleaning
receptacle holding a cleaning compound and being piped to the
lapping machine(s); a waste receptacle holding waste that is piped
from the lapping machine(s); a first pump piped to said virgin
receptacle, to said cleaning receptacle, and to the lapping
machine(s), said first pump pumping the lapping compound from said
virgin receptacle to the lapping machine(s) and pumping the
cleaning compound from said cleaning receptacle to the lapping
machine(s); a second pump piped to said cleaning receptacle, to
said waste receptacle, and to the lapping machine(s), said second
pump pumping waste from the lapping machine(s) to said waste
receptacle; and a three-way valve located downstream said virgin
and cleaning receptacles and upstream said first pump, said
three-way valve regulating fluid-flow between said virgin
receptacle, said cleaning receptacle, and said first pump.
Description
TECHNICAL FIELD
[0001] This invention relates to lapping machines and more
particularly to sweetening and cleaning systems for lapping
machines.
BACKGROUND OF THE INVENTION
[0002] Lapping machines are conventionally used to rub two surfaces
together with an abrasive lapping compound between them. In the
automotive industry, gears are often lapped together to, among
other things, produce smooth surfaces and tight tolerances between
the gears. Over time the lapping compound can become contaminated
and less effective, and build-up can accumulate in piping
components.
[0003] One example of a slurry managing system is U.S. Pat. No.
5,799,643 to Miyata et al. The system is used with wire saws for
cutting wafers. A mixing tank mixes base oil from a dispersing tank
with abrasive grains from a hopper to produce a mixed slurry. The
mixed slurry is held in a reserve tank before it is pumped through
the wire saws and then to a slurry waste tank. From the waste tank,
the waste is decanted and filtered, and the remaining slurry is
directed back to the mixing tank. Simultaneously, fresh slurry is
provided to the wire saws, thus replacing the waste. This slurry
managing system, however, does not have both a sweetening and
cleaning mode.
SUMMARY OF THE INVENTION
[0004] One aspect of the invention includes a sweetening and
cleaning system that can be used with one or more lapping machines
to sweeten a lapping compound in a sweetening mode, and to clean
parts of the system itself and parts of the one or more lapping
machines with a cleaning compound in a cleaning mode. The system
may comprise a virgin receptacle to hold the lapping compound, a
cleaning receptacle to hold the cleaning compound, a waste
receptacle to hold waste, and at least one pump to pump the
compounds and the waste throughout the system.
[0005] Another aspect of the invention provides a method of
sweetening and cleaning one or more lapping machines which may
comprise a virgin receptacle for holding a lapping compound, a
cleaning receptacle for holding a cleaning compound, and a waste
receptacle for holding waste. The method comprises at least a
sweetening mode and a cleaning mode. The sweetening mode may
include removing waste out of the one or more lapping machines and
putting it into the waste receptacle, and adding the lapping
compound to the one or more lapping machines. The cleaning mode may
include purging the one or more lapping machines of waste, and
priming the one or more lapping machines with the lapping
compound.
[0006] Yet another aspect of the invention includes a sweetening
and cleaning system that can be used with one or more lapping
machines that may comprise a virgin receptacle for holding a
lapping compound, a cleaning receptacle for holding a cleaning
compound, a waste receptacle for holding waste, a first pump, a
second pump, and a three-way valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Preferred exemplary embodiments of the invention will
hereinafter be described in conjunction with the appended Figure
which is a schematic representing a sweetening and cleaning system
of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0008] Referring now to the Figure, it shows an embodiment of a
sweetening and cleaning method and system 10 that can be used with
one or more lapping machines 12, such as a group of six lapping
machines (not shown). The system may be retrofitted on a group of
lapping machines, or installed as part of the original equipment of
the machines. In any case, the sweetening and cleaning system 10
sweetens a lapping compound that is used in the lapping machines 12
by routinely improving the lapping compound during a sweetening
mode, and the system 10 cleans parts of itself and parts of the
lapping machines 12 by using a cleaning compound during a cleaning
mode. The sweetening and cleaning system 10 may include a virgin
receptacle 14 that holds the lapping compound, a cleaning
receptacle 16 that holds the cleaning compound, and a waste
receptacle 18 that holds waste. Various piping components may also
be included that control fluid-flow between the receptacles and the
lapping machines 12, and a programmable logic controller (PLC) 20
may be included to serve as the control center for the system.
[0009] The lapping machines 12 are commonly used to lap surfaces
such as gears for an automobile. As mentioned, the sweetening and
cleaning system 10 can be retrofitted on one or more lapping
machines 12. If so, the system's hardware components are installed
to the existing lapping machines 12, and the system's software is
programmed to communicate with software on the lapping machines 12,
and vice versa. Each lapping machine 12 may include a machine cell
22 where the actual lapping of the parts takes place, and a machine
reservoir 24 to collect and hold lapping compound as it is being
used in the machine. Some lapping machines have a high level sensor
26 and a low level sensor 28 to sense when the compound in the
machine reservoir 24 is at a respective high and low level. In
addition to communicating with these level sensors, the sweetening
and cleaning system 10 may further include a first level sensor 30
and a second level sensor 32 that are equipped in the machine
reservoir 24. The first level sensor 30 is one that can be manually
adjusted, such as the known vertical stem type. This way the
machine operator can calibrate, or set, the sensor to determine the
amount of waste that is pumped out of the machine reservoir 24
during the sweetening mode as will be described below. The second
sensor 32 is set to a desired level to determine the amount of
lapping compound that is pumped into the machine reservoir 24 also
during the sweetening mode. Lastly, a machine pump 34 may be
included with each lapping machine 12 to circulate compound through
the machine.
[0010] In other embodiments, the PLC 20 could be programmed for
timed events. For example, in the sweetening mode, the system pumps
could be energized for a predetermined amount of time in order to
pump waste out of the machine reservoir 24, and then to pump
lapping compound into the machine reservoir. Here, the first and
second level sensors 30 and 32 may still be provided, but are only
in use when the compound or waste level reaches them and the
particular fluid level in the machine reservoir needs to be
corrected. In other words, the timed events may result in a fluid
level that is either below the first level sensor 30 or above the
second level sensor 32. This can occur because of a circumstance
known as drift, whereby one or more pumps produces an inexact (less
or more) amount of fluid into or out of the machine reservoir 24.
In one example, during a timed event in the sweetening mode,
lapping compound may reach the second level sensor 32 before the
timed event has expired. In this case, the PLC 20 would cut-short
the timed even such that the fluid level in the machine reservoir
24 does not exceed the second level sensor 32.
[0011] The virgin receptacle 14 holds and stores the virgin, or
pure, lapping compound for the sweetening and cleaning system 10.
Suitable receptacles will be known to those skilled in the art. In
this embodiment, the virgin receptacle 14 is a single 275 gallon
receptacle, but more than one (larger or smaller) can be used. For
example, two virgin receptacles can be stacked one on top of the
other with an automatic control valve between the two that can be
set to open by the PLC 20 when a level sensor in one indicates a
low level. The lapping compound itself will depend on, among other
things, the particular lapping application. One lapping compound
that is suitable for automotive gears is composed of silicon
carbide crystals, mineral oil, and other additives, and is supplied
by Foretech Products, Inc. in Whitmore Lake, Mich. A low level
sensor 36 may be provided in the virgin receptacle 14 to sense when
the lapping compound is at a predetermined low level. The low level
sensor 36 is set so that when it is triggered, enough lapping
compound remains in the virgin receptacle 14 to complete the
sweetening mode in one lapping machine 12. Similarly, an emergency
low level sensor 38 may be provided in the virgin receptacle 14 and
set below the low level sensor 36 to trigger when the receptacle
needs to be refilled or replaced with lapping compound. Both of
these level sensors can be of the known doppler type, tuning fork
type, or the like. Furthermore, a quick-connect fitting (not shown)
may be provided on the virgin receptacle 14 to connect and
disconnect the receptacle with the piping components.
[0012] The cleaning receptacle 16 holds and stores the cleaning
compound for the sweetening and cleaning system 10. Like the virgin
receptacle, the cleaning receptacle 16 is a single 275 gallon
receptacle and there can be more than one that is larger or
smaller. The cleaning compound itself is a solution that removes
build-up in the piping components and the lapping machines 12 from
the particular lapping operation. One suitable cleaning compound is
mineral seal oil. The cleaning receptacle 16 may have a low level
sensor 40 and a high level sensor 42. The low level sensor 40 is
set to trigger when the cleaning compound in the cleaning
receptacle 16 is low and needs to be refilled or replaced, and
conversely the high level sensor 42 is set to trigger when the
cleaning compound is at a high level. Again, these sensors can be
of the known doppler type, tuning fork type, or the like. The
cleaning receptacle 16 may also have a quick-connect fitting (not
shown) to connect and disconnect the receptacle with the piping
components.
[0013] The waste receptacle 18 holds and stores waste for the
sweetening and cleaning system 10. It too is a single 275 gallon
receptacle and there can be more than one that is larger or
smaller. The waste itself is a mixture of used lapping compound
which may contain metallic fines removed during the lapping
process, dulled silicon carbide crystals, tramp oils including
machine lubrications, and the like, coming from the lapping
machines 12; essentially the waste comprises lapping compound that
is now less effective due to the lapping process. A high level
sensor 44 and an emergency high level sensor 46 may be provided in
the waste receptacle 18. The high level sensor 44 is set to trigger
when the waste in the receptacle reaches a high level while still
having enough volume to complete a sweetening event in one lapping
machine 12. And the emergency high level sensor 46 is set to
trigger when the waste reaches a predetermined higher level
indicating that the waste receptacle 18 needs to be emptied. These
sensors can be of the known doppler type, tuning fork type, or the
like. A quick-connect fitting (not shown) may also be provided on
the waste receptacle 18 to connect and disconnect the receptacle
with the piping components.
[0014] As mentioned, the sweetening and cleaning system 10 may
include various piping components including a first pump 48 that
pumps the lapping compound from the virgin receptacle 14 and also
pumps the cleaning compound from the cleaning receptacle 16; and a
second pump 50 at each lapping machine 12 that pumps waste from the
respective lapping machine directly into the waste receptacle 18.
In this embodiment, both pumps are of the positive displacement
type, specifically a peristaltic pump. But those skilled in the art
will appreciate that other types of pumps with different flow rates
can be used depending on the particular lapping operation. Examples
of suitable peristaltic pumps include those supplied by
Watson-Marlow Bredel (www.watson-marlow.com) like the SPX 40 style
pump for the first pump 48 and the SPX 25 style pump for the second
pump 50. The first pump 48 is set to produce a laminar flow when
activated in the sweetening mode, and a turbulent flow when
activated in the cleaning mode. And the second pump 50 is set to
produce a laminar flow when activated. Of course, the exact flow
rates can differ from application-to-application, and may depend
on, among other things, the pumps and pipes used. Likewise,
sustaining laminar and turbulent flow in a particular application
may depend on, among other things, pipe diameter and pipe routing.
Furthermore, running the pumps at constant flow rates provides
constant displacement rates which simplifies some system
calculations including the length of time that the pumps should be
energized to empty or fill the machine reservoir 24 during some
embodiments of the sweetening and cleaning modes.
[0015] The first pump 48 is a single pump located near the
receptacles and is piped through other piping components to the
virgin receptacle 14, the cleaning receptacle 16, and the lapping
machines 12, and then eventually to the waste receptacle 18. In
particular, the virgin and cleaning receptacles are piped to the
pump's inlet, and the pump's outlet is piped to the lapping
machines 12. In other embodiments, the first pump 48 could be a
pair of pumps with one directly connected to the virgin receptacle
14 and the other directly connected to the cleaning receptacle 16,
and then both leading to the lapping machines 12. The second pump
50, on the other hand, is located near each lapping machine 12 and
piped to the waste receptacle 18, and the lapping machine 12, and
could be piped to the cleaning receptacle 16. The lapping machine
12 is piped to the second pump's inlet, and the pump's outlet can
be piped to both the cleaning and waste receptacles 16 and 18.
[0016] Other piping components may include various valves and
filters installed in the piping of the sweetening and cleaning
system 10. As shown, a three-way valve 52 is installed between the
virgin receptacle 14 and the cleaning receptacle 16, and the first
pump 48. One example of a suitable three-way valve is an automatic
pneumatic valve with a first inlet port, a second inlet port, and
an outlet port (none specifically shown) and include those supplied
by Co-ax Valves Inc., Penndel, Pa. (www.coaxvalves.com); another
example of a suitable three-way valve is of the rubber-lined pinch
type. The three-way valve 52 permits or prevents fluid-flow between
the virgin and cleaning receptacles and the first pump by being
deactuated, or deenergized, open from the first inlet port to the
outlet port allowing fluid-flow between the virgin receptacle 14
and the first pump 48, and being actuated, or energized, open from
the second inlet port to the outlet port allowing fluid-flow
between the cleaning receptacle 16 and the first pump 48. That
being so, the three-way valve 52 is located downstream the virgin
receptacle 14 having the first inlet port piped to the virgin
receptacle, downstream the cleaning receptacle 16 having the second
inlet port piped to the cleaning receptacle, and upstream the first
pump 48 having the outlet port piped to the first pump.
[0017] A first two-way valve 54 is installed downstream the lapping
machines 12, particularly downstream the second pump 50, and
upstream the cleaning receptacle 16 to permit or prevent fluid-flow
therebetween. Preferably, the first two-way valve 54 is installed
close to the cleaning receptacle 16 in order to inhibit fluid from
settling and drying therebetween. One example of a suitable two-way
valve is an automatic pneumatic valve having an inlet port piped to
the second pump 50 and an outlet port piped to the cleaning
receptacle 16; another example of a suitable two-way valve is of
the rubber-lined pinch type. The first two-way valve 54 is
deactuated, or deenergized, closed to prevent fluid-flow, and
actuated, or energized, open to allow fluid-flow. A second two-way
valve 56 is installed downstream the lapping machines 12,
particularly downstream the second pump 50, and upstream the waste
receptacle 18 to permit or prevent fluid-flow therebetween.
Preferably, the second two-way valve 56 is installed close to the
waste receptacle 18 in order to inhibit fluid from settling and
drying therebetween. An inlet port is piped to the second pump 50
and an outlet port is piped to the waste receptacle 18. The second
two-way valve 56 is deactuated, or deenergized, closed to prevent
fluid-flow, and actuated, or energized, open to allow
fluid-flow.
[0018] A third two-way valve 58 is installed downstream the first
pump 48 and upstream each lapping machine 12 to permit or prevent
fluid-flow therebetween. An inlet port is piped to the first pump
48 and an outlet port is piped to the lapping machine 12. The third
two-way valve 58 is deactuated, or deenergized, closed to prevent
fluid-flow, and actuated, or energized, open to allow fluid-flow.
Furthermore, a fourth two-way valve 60 is installed downstream the
first pump 48 and upstream the cleaning receptacle 16 to permit or
prevent fluid-flow therebetween. An inlet port is piped to the
first pump 48 and an outlet port is piped to the cleaning
receptacle 16. The fourth two-way valve is deactuated, or
deenergized, closed to prevent fluid-flow, and actuated, or
energized, open to allow fluid-flow. All of the above two-way
valves can be of the automatic pneumatic type, the rubber-lined
pinch type, or the like, and can be supplied by the above Co-ax
Valves Inc.
[0019] A first filter 62 may be installed downstream the lapping
machines 12, particularly downstream the second pump 50, and
upstream the cleaning receptacle 16 to remove impurities in the
cleaning compound during the cleaning mode. Likewise, a second
filter 64 may be installed downstream the machine reservoir 24 of
each lapping machine 12 and upstream the machine cell 22,
particularly downstream the machine pump 34 to remove impurities in
compound traveling therethrough. One example of suitable filters
for the first and second filters can be of the liquid bag type like
those supplied by Filtration Group Inc., Joliet, Ill.
(www.filtrationgroup.com).
[0020] Still other piping components may include numerous ball
valves installed in the sweetening and cleaning system 10. The ball
valves manually permit and prevent fluid-flow by turning a handle.
All the ball valves are normally open, and can be closed to isolate
a particular section of the system or a particular component in
order to service that section or component. One example of suitable
ball valves are of the known manual full port type that open and
close to respectively permit and prevent fluid-flow. As shown, a
ball valve 66 is installed in the piping exiting the virgin
receptacle 14, and a ball valve 68 is installed in the piping
exiting the cleaning receptacle 16. Another ball valve 70 is
installed before the first pump 48, and a ball valve 72 is
installed after the first pump 48. A ball valve 74 is installed
downstream the first pump 48, and a ball valve 76 is installed
downstream the third two-way valve 58. A ball valve 78 is installed
in the piping past the machine reservoir 24, a ball valve 80 is
installed before the second pump 50, and a ball valve 82 is
installed after the second pump 50. Furthermore, three ball valves
are installed downstream the second pump 50: a ball valve 84 is
installed in the piping past the second pump 50, a ball valve 86 is
installed in the piping upstream the second two-way valve 56, and a
ball valve 88 is installed in the piping upstream the first two-way
valve 54.
[0021] Moreover, the sweetening and cleaning system 10 may include
a pair of pressure relief valves to protect the first and second
pumps 48 and 50. One example of suitable relief valves can be of
the known spring-loaded type. To protect the pumps, a relief valve
90 is installed in the piping immediately after the first pump 48
to provide a first relief path 92 leading back to, or near, the
first pump's entrance; and a relief valve 94 is installed
immediately after the second pump 50 to provide a second relief
path 96 leading back to, or near, the second pump's entrance. Each
of the relief valves are set to open at a predetermined pressure
such as 75 p.s.i., and are fitted with a sensor (not shown), such
as a proximity sensor, to sense when the particular relief valve is
opened. For example, if the third two-way valve 58 fails to open
during one of the modes, pressure can build-up in the piping over
75 p.s.i. thus triggering the relief valve 90 located adjacent the
first pump 48. This way the pressure in the piping is kept under
about 75 p.s.i. The sensor sends an electrical signal to the PLC 20
to inform the machine operator of a possible failure or
malfunction.
[0022] A compound analog vacuum gauge 98 and a vacuum switch 100
may be installed immediately before the respective first pump 48,
and a compound analog vacuum gauge 102 and a vacuum switch 104 may
be installed immediately before the second pump 50. An additional
pressure gauge 106 may be installed immediately after the first
pump 48, and a pressure gauge 108 may be installed immediately
after the second pump 50. All of the gauges and switches can be
fitted with a diaphragm isolator to prevent fluids from contacting
the components. The vacuum gauges measure the vacuum at their
respective locations and send that reading to the PLC 20, and the
vacuum switches trip (close the switch) and can be calibrated to
about 15 in Hg or more or less depending on the particular
application. Furthermore, a pulsation dampener 110 may be installed
after the first pump 48, and a pulsation dampener 112 may be
installed after the second pump 50. The pulsation dampeners reduce
hydraulic shock in the sweetening and cleaning system 10 that can
come from those pumps. A single pressure transducer 114 may be
installed after the first pump 48 to sense a fluid pressure thereat
and produce an associated electrical signal to the PLC 20. In some
instances, fluid in a particular valve may harden or otherwise clog
a valve. This condition would be sensed by the pressure transducer
114 because of an associated build-up of pressure. When this
happens, the PLC 20 can be programmed to pulse the particular valve
open and close, while increasing the pressure thereat by energizing
a pump. This will usually loosen up the clogged valve. Suitable
pressure transducers can be supplied by Ashcroft.
[0023] The piping itself is designed to reduce hydraulic shock in
the sweetening and cleaning system 10. For example, all of the
pipes in the system have a uniform diameter such as 1.5 inches, and
the pipes change directions at about 45.degree. laterals instead of
T-connections. In some embodiments, the pipes change directions in
a sweeping radius that is a multiple of six times their diameter.
Pipes 116 supply the lapping compound and the cleaning compound to
the lapping machine 12, and pipes 118 discharge waste and the
cleaning compound to the respective waste receptacle 18 and
cleaning receptacle 16. A rubber hose (not shown) may be looped
between the pipes 116 close to the first pump 48. The looped hose
can also reduce hydraulic shock. And all of the pipes in the
sweetening and cleaning system 10 can be provided with
quick-connect fittings (not shown) to connect and disconnect the
pipes to other piping components, such as those supplied by
Victaulic, Easton, Pa. (www.victaulic.com).
[0024] As mentioned, the PLC 20 serves as the control center for
the sweetening and cleaning system 10. The PLC 20 communicates with
the sweetening and lapping system by reading inputs from the system
including, for example, the various level sensors in the
receptacles and the machine reservoir, the pressure transducer 114,
and the like. Also, the PLC 20 is programmed to send outputs to
control the various piping components including, for example,
energizing and deenergizing the first pump 48 and the second pump
50, and energizing and deenergizing the three-way valve 52 and the
two-way valves 54, 56, 58, and 60. Moreover, the PLC 20
communicates with the lapping machines 12 by, for example, reading
inputs from the high and low level sensors 26 and 28. A
human-machine-innerface (HMI) 120 may be provided with the PLC 20
to interact with the machine operator by allowing everyday controls
including manually switching between the modes, giving the status
of the sweetening and cleaning system 10, reporting alarms, and the
like. As shown, the HMI 120 is located near the receptacles or at
the lapping machines 12. Various controls panels (not shown) may
also be provided in the sweetening and cleaning system 10 to house
various electrical components of the PLC 20.
[0025] A first skid 122 and a second skid 124 may be provided in
the sweetening and cleaning system 10 to carry and transport the
components of the system. In this embodiment, the first skid 122 is
constructed of steel to carry the virgin receptacle 14, the
cleaning receptacle 16, the waste receptacle 18, the PLC 20, and
the first pump 48. Likewise, the second skid 124 is constructed of
steel to carry the second pump 50 and the other various piping
components adjacent the second pump including the pressure gauge
108, pulsation dampener 112, and others. The second skid 124 can be
equipped with wheels (not shown) on its bottom, and the various
piping components can be fitted with rubber, or otherwise be
flexible, so that the second skid can be moved. The first skid 122
is located farther away from the lapping machines 12 than the
second skid 124.
[0026] Once the sweetening and cleaning system 10 is installed and
activated, the system routinely improves the lapping compound used
in the lapping machines 12, and routinely cleans itself and parts
of the lapping machines 12. To do this, the PLC 20 is programmed to
control the sweetening and cleaning modes. For example, the PLC 20
automatically initiates the sweetening mode after, among other
possible events, a certain number of parts have been lapped in a
particular lapping machine 12. For instance, after fifty parts are
lapped, the lapping machine 12 temporarily stops lapping parts
while the sweetening mode is run on that machine. The PLC 20 also
automatically initiates the cleaning mode after, among other
possible events, a certain amount of time has lapsed. For instance,
after fourteen or thirty days, the particular lapping machine 12
temporarily stops lapping parts while the cleaning mode is run on
that machine. The PLC 20 issues a command to clean each lapping
machine 12. The operator at each machine can then either accept or
reject that command. If accepted, that lapping machine ceases
lapping parts while the cleaning mode is performed; and if
rejected, the machine continues lapping parts. In this sense, the
sweetening and cleaning system 10 is automatic--both the sweetening
and cleaning modes are initiated after certain events. Still, the
sweetening and cleaning system 10 can be manually operated. That
is, the sweetening and cleaning modes can be initiated by the
machine operator at anytime. For example, the machine operator can
run the cleaning mode before the predetermined days through
commands on the PLC 20 .
[0027] As explained, the sweetening and cleaning modes are run on a
single lapping machine 12 at a time in a sequential order, that is,
beginning with the lapping machine located physically closer to the
first skid 122. This way the particular fluid is already stacked,
or loaded in the pipes, for the next lapping machine which can save
pumping work as compared to starting at the lapping machine farther
away without stacked fluid. If two lapping machines 12 of the group
are triggered for the sweetening mode at similar times, the one
that triggers first in time will be sweetened first while the one
that triggers second in time will be sweetened second. In other
embodiments with piping, the sweetening or cleaning mode could be
run on more than one lapping machine 12 simultaneously.
[0028] When the sweetening and cleaning system 10 is first
installed on one or more lapping machines 12, the system and the
machines have to be initially prepared, or primed, before the
system is activated. Priming essentially involves filling the
system with the lapping compound. This procedure can also
constitute one part of the cleaning mode as will be described
below. The sweetening and cleaning system 10 and the lapping
machines 12 are filled with the lapping compound by deenergizing
the three-way valve 52 to allow fluid-flow from the virgin
receptacle 14, energizing the first pump 48 on, and energizing the
third two-way valve 58 open. The other valves 54, 56, and 60 are
closed, and the second pump 50 is deenergized off. The lapping
compound is pumped from the virgin receptacle 14, through the first
pump 48, through the pipes 116, and added into the machine
reservoir 24. The machine reservoir 24 is filled with the lapping
compound until the second level sensor 32 triggers; or until the
predetermined time has expired; then the first pump 48 is
deenergized off and the third two-way valve 58 is deenergized
close. Now the sweetening and cleaning system 10 is ready for the
sweetening mode.
[0029] As mentioned, the sweetening mode can be initiated after a
certain event. Once initiated, the waste is first removed out of
the machine reservoir 24. The second pump 50 is energized on and
the second two-way valve 56 is energized open. The other valves 54,
58, and 60 are closed, and the first pump 48 is deenergized off.
The waste is pumped from the machine reservoir 24, through the
second pump 50, through the pipes 118, and into the waste
receptacle 18. The waste is pumped out of the machine reservoir 24
until the first level sensor 30 triggers or until the predetermined
time has expired; then the second pump 50 is deenergized off and
the second two-way valve 56 is deenergized close. After the waste
is removed, the lapping compound is added to the machine reservoir
to improve the compound therein. To do this, the three-way valve 52
is deenergized to allow fluid-flow from the virgin receptacle 14,
the first pump 48 is energized on, and the third two-way valve 58
is energized open. The other valves 54, 56, and 60 are closed, and
the second pump 50 is deenergized off. The lapping compound is
pumped from the virgin receptacle 14, through the first pump 48,
through the pipes 116, and added into the machine reservoir 24
until the second level sensor 32 triggers or until the
predetermined time has expired. Now, waste has been pumped out of
the machine reservoir 24 and replaced by lapping compound thus
improving the compound in the lapping machine 12 and thus
completing a sweetening event for that machine.
[0030] Once the cleaning mode is initiated, the lapping machine 12
is first purged. The waste is removed out of the machine reservoir
24 and into the waste receptacle 18. The second pump 50 is
energized on and the second two-way valve 56 is energized open. The
other valves 54, 58, and 60 are closed, and the first pump 48 is
deenergized off. The waste is pumped out of the machine reservoir
24 until the low level sensor 28 triggers until all of the level
sensors 32, 30 and 28 show no fluid; then the waste is continually
pumped out of the reservoir for a predetermined amount of time, for
example 20 seconds, to scavenge any remaining waste to ensure that
the waste is almost entirely emptied out of the reservoir. After
the predetermined 20 seconds, the cleaning compound begins being
added to the machine reservoir 24. To do this, the three-way valve
52 is energized to allow fluid-flow from the cleaning receptacle
16, the first pump 48 is energized on, and the third two-way valve
58 is energized open.
[0031] The cleaning compound continues being added to the machine
reservoir 24 after the predetermined 20 seconds for another
predetermined amount of time that is sufficient to replace the
volume of fluid in the pipes. The reservoir is filled until the
second level sensor 32 triggers. If the second level sensor 32
triggers before the predetermined amount of time has expired, then
the first pump 48 is deenergized so that cleaning compound is no
longer added to the machine reservoir. In any case, cleaning
compound can be added to the machine reservoir 24 and the
associated pipes, including pipes 116 and 118, so that cleaning
compound is substantially the only fluid in the pipes and
reservoir.
[0032] Now, the cleaning compound is continuously recirculated
through a bypass loop and through the lapping machine 12 to clean
the associated flow-paths. The bypass loop is created by energizing
the three-way valve 52 to allow fluid-flow from the cleaning
receptacle 16, energizing the first pump 48 on, energizing the
fourth two-way valve 60 open, and energizing the first two-way
valve 54 open. The second and third two-way valves 56 and 58 are
closed, and the second pump 50 is deenergized off. The cleaning
compound is continuously recirculated through the bypass loop to
remove build-up and the like therein for a predetermined amount of
time. Particularly, the cleaning compound is pumped from the
cleaning receptacle 16, through the first pump 48, through the
pipes 116, past the fourth two-way valve 60, through the pipes 118,
through the first filter 62, and back into the cleaning receptacle
16. Simultaneously, the cleaning compound is continuously
recirculated through the lapping machine 12 for the same
predetermined amount of time. The machine pump 34 pumps the
cleaning compound from the machine reservoir 24, through the second
filter 64 (if provided), through the machine cell 22, and back into
the machine reservoir 24. After the predetermined time is up, the
now-used cleaning compound is routed to the waste receptacle 18,
and the sweetening and cleaning system 10 and the cleaned lapping
machines 12 are then primed with the lapping compound as described
above.
[0033] The bypass loop is also used when the machine operator
selects a bypass mode on the PLC 20. The bypass mode then diverts
fluid-flow away from the particular lapping machine 12, for
example, for servicing the lapping machine or in case of a failure.
This way the sweetening and cleaning system 10 is not shutdown
altogether and the other lapping machines in the group that are not
being serviced are sweetened and cleaned.
[0034] Those skilled in the art will appreciate that the above
description of the sweetening and cleaning system and method can
vary with different lapping operations. For example, the above
described components may not necessarily be installed in the
particular location described or even exist in other systems while
still coming within the scope of this invention. And indeed, the
sweetening and cleaning modes may be performed in different ways
while still coming within the scope of this invention.
[0035] It is to be understood that the foregoing description is not
a definition of the invention, but is a description of one or more
preferred exemplary embodiments of the invention. The invention is
not limited to the particular embodiment(s) disclosed herein, but
rather is defined solely by the claims below. Furthermore, the
statements contained in the foregoing description relate to
particular embodiments and are not to be construed as limitations
on the scope of the invention or on the definition of terms used in
the claims, except where a term or phrase is expressly defined
above. Various other embodiments and various changes and
modifications to the disclosed embodiment(s) will become apparent
to those skilled in the art. All such other embodiments, changes,
and modifications are intended to come within the scope of the
appended claims.
[0036] As used in this specification and claims, the terms "for
example," "for instance," and "such as," and the verbs
"comprising," "having," "including," and their other verb forms,
when used in conjunction with a listing of one or more components
or other items, are each to be construed as open-ended, meaning
that the listing is not to be considered as excluding other,
additional components or items. Other terms are to be construed
using their broadest reasonable meaning unless they are used in a
context that requires a different interpretation.
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