U.S. patent application number 11/130974 was filed with the patent office on 2005-10-06 for fuel pump gasket.
This patent application is currently assigned to Suntec Industries Incorporated. Invention is credited to Hunsberger, Dale L., Price, Jack A..
Application Number | 20050220633 11/130974 |
Document ID | / |
Family ID | 35054477 |
Filed Date | 2005-10-06 |
United States Patent
Application |
20050220633 |
Kind Code |
A1 |
Hunsberger, Dale L. ; et
al. |
October 6, 2005 |
Fuel pump gasket
Abstract
Provided is a gasket for a fuel pump unit configured with a
second outlet port for accommodating a pressure sensor to monitor
the downstream pressure of pumped fuel. The gasket is adapted for
placement between a pump cover incorporating the second outlet port
and a pump body containing a gear pump. Providing fluid
communication between a first outlet port downstream of the gear
pump and the second outlet port is a passageway disposed through
the pump cover and pump body. To avoid obstructing the passageway,
the gasket includes an aperture. To prevent high pressure fuel from
being forced through the gasket and leaked from the pump unit, the
gasket includes a leakage collection channel having a first leg, a
second leg and an intermediate portion surrounding the aperture.
The leakage collection channel is adapted to return leaked fuel to
a low pressure reservoir between the pump cover and pump body.
Inventors: |
Hunsberger, Dale L.;
(Bowling Green, KY) ; Price, Jack A.; (Freeport,
IL) |
Correspondence
Address: |
REINHART BOERNER VAN DEUREN LTD.
483 NORTH MULFORD ROAD
SUITE 7
ROCKFORD
IL
61107
US
|
Assignee: |
Suntec Industries
Incorporated
Glasgow
KY
|
Family ID: |
35054477 |
Appl. No.: |
11/130974 |
Filed: |
May 17, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11130974 |
May 17, 2005 |
|
|
|
10461152 |
Jun 13, 2003 |
|
|
|
60571834 |
May 17, 2004 |
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Current U.S.
Class: |
417/279 |
Current CPC
Class: |
F04C 2/086 20130101;
F04C 15/0034 20130101; F04C 2/101 20130101 |
Class at
Publication: |
417/279 |
International
Class: |
F04B 049/00 |
Claims
What is claimed is:
1. A fuel pump unit for pumping fuel from a fuel tank to a
combustion chamber, the fuel pump unit comprising: a gear pump
adapted to pump fuel; a pump body housing the gear pump, the pump
body including an outlet port downstream of the gear pump for
outputting pumped fuel; a pump cover mounted to the pump body; a
local reservoir defined between the pump body and the pump cover,
the local reservoir being upstream of the gear pump; a pressure
gauge port in the pump cover connected by a passageway extending
through the pump cover and the pump body to communicate with the
outlet port; and a gasket between the pump body and the pump cover
to seal the local reservoir, the gasket including an aperture
corresponding to the passageway to allow communication
therethrough, the gasket including a leakage collection channel
partially surrounding the aperture, the leakage collection channel
having a first straight leg, a second straight leg, and a straight
intermediate portion interconnecting the first and second straight
legs, the leakage collection channel adapted to communicate and
return leaked fuel from the passageway to the local reservoir to
prevent external fuel leakage.
2. The fuel pump unit of claim 1, wherein the leakage collection
channel is located partially between aperture and an outer
periphery of the gasket.
3. The fuel pump unit of claim 2, wherein the gasket includes a
sealing ring of gasket material surrounding the aperture, the
sealing ring separating the aperture and the leakage collection
channel and adapted to prevent leakage of fuel from the passageway
between the pump cover and the pump body, and in the event of
leakage past the sealing ring leaked fluid is adapted to be
collected in the collection channel and returned to local
reservoir.
4. The leakage channel of claim 3, wherein at least one leg is in
fluid communication with the local reservoir.
5. The fuel pump unit of claim 4, wherein the intermediate portion
is arranged between the aperture and the external environment, the
first and second straight legs projecting inward from the
intermediate portion toward the reservoir.
6. The fuel pump unit of claim 1, wherein the gasket comprises a
generally planar sheet, the collection channel extending completely
through the generally planar sheet.
7. The fuel pump unit of claim 1, wherein the gasket includes a
second redundant aperture and a second redundant leakage collection
channel proximate the second redundant aperture symmetric to the
first aperture and first leakage connection channel, the redundant
aperture and the redundant leakage collection channel being
non-functional when mounted between the pump cover and the pump
body.
8. A pump gasket for sealing a low pressure local reservoir defined
between a pump body having a downstream high pressure outlet port
and a pump cover having a passage, the gasket comprising: a
generally planer gasket sheet having an outer periphery and an
inner periphery defining an opening; an aperture disposed through
the gasket sheet, the aperture corresponding to the passage and the
outlet port; and a leakage collection channel in the gasket sheet,
the leakage collection channel including a first straight leg, a
second straight leg, and a straight intermediate portion
interconnecting the first and second straight legs, the leakage
collection channel partially surrounding the aperture and adapted
to communicate with the low pressure local reservoir when the pump
gasket is mounted between the pump body and the pump cover.
9. The pump gasket of claim 8, wherein the first and second legs
are located on opposing sides of the aperture.
10. The pump gasket of claim 9, wherein the leakage collection
channel is disposed through the gasket sheet.
11. The pump gasket of claim 8, wherein the outer periphery is
generally rectangular and the inner periphery is generally
circular.
12. The pump gasket of claim 11, further comprising a plurality of
bolt holes, each bolt hole corresponding a corner of the
rectangular outer periphery.
13. The pump gasket of claim 8, wherein the gasket sheet is
distinguished into an upper first quarter, an upper second quarter,
a lower first quarter, and a lower second quarter, and wherein the
aperture and the leakage collection channel are located in the
upper first quarter.
14. The pump gasket of claim 8, wherein the first straight leg and
the second straight leg intersect the straight intermediate portion
at defined corners.
15. The pump gasket of claim 13, further comprising a second
redundant aperture and a second redundant leakage collection
channel, the second aperture and second leakage collection channel
located through the upper second quarter.
16. The pump gasket of claim 15, wherein the second redundant
leakage collection channel includes a first straight leg, a second
straight leg, and an straight intermediate portion interconnecting
the first and second legs.
17. The pump gasket of claim 16, wherein the gasket sheet is
symmetrical between the upper and lower first quarters and the
upper and lower second quarters.
18. A pump gasket for sealing a low pressure local reservoir
defined between a pump body having a downstream high pressure port
and a pump cover having a slanted passage oriented at a
non-perpendicular angle to the mating surfaces of the pump body and
pump cover, the gasket comprising: a generally planer gasket sheet
having an outer periphery and an inner periphery defining an
opening; an aperture disposed through the gasket sheet, the
aperture corresponding to the passage and the outlet port; a
leakage collection channel in the gasket sheet, partially
surrounding the aperture and in fluid communication with low
pressure reservoir; and means in the planar gasket sheet between
the channel and the aperture for providing sufficient strength
planar gasket sheet to prevent leakage along the slanted passage to
the channel when mounted between the pump body and pump cover and
when the slanted passage is subjected to high fuel pressure.
19. The pump gasket of claim 18, further comprising a plurality of
bolt holes disposed through the gasket sheet material.
20. The pump gasket of claim 19, wherein the gasket sheet has a
rectangular outer periphery and a circular inner periphery.
21. The pump gasket of claim 19, wherein the means includes a
plurality of legs, each adjacent set of said legs intersecting at a
defined corner.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 10/461,152, entitled "Port Configuration for
Fuel Pump Unit for Facilitating Pressure Feedback" filed on Jun.
11, 2003. This patent application claims the benefit of U.S.
Provisional Patent Application No. 60/571,834, filed on May 17,
2004.
FIELD OF THE INVENTION
[0002] The present invention relates generally to sealing devices
and more particularly to gaskets for sealing fuel pumps. The
present invention finds particular use in fuel pumps having a port
configuration of the type disclosed in U.S. application Ser. No.
10/461,152.
BACKGROUND OF THE INVENTION
[0003] Fuel oil pump units are used to pump fuel oil to oil burning
furnaces for heating residential and commercial buildings. By
virtue of the application and where furnaces are located, fuel oil
pump units often are required to fit a small confined area of a
predetermined package size. Examples of fuel oil pump units are
disclosed in U.S. Pat. Nos. 3,360,190; 3,446,230; 3,446,231;
3,446,232; 3,566,901; 4,021,155; 4,171,939; 4,255,093; 4,391,580;
4,685,871; 4,728,271; 4,856,553; 4,858,884; 4,898,523; 4,958,997;
5,145,328; 5,316,457; 5,346,174; and 5,692,680, and application
Ser. Nos. 10/017,153 and 10/115,742, all assigned to the present
assignee and all of which are hereby incorporated by reference in
their entireties.
[0004] As disclosed in these patents and applications, the basic
structural design for a fuel oil pump unit typically comprises a
pump body often formed of cast iron and a pump cover often formed
of aluminum. The pump body typically contains a crescent type gear
pump that pumps fuel oil from a local reservoir defined between the
pump body and pump cover that is supplied oil from a fuel oil
storage tank. A gasket may be provided for sealing the local
reservoir. The downstream portion of the gear pump is in
communication with a nozzle outlet passage in the pump body that is
adapted to be connected to the combustion chamber of a furnace. The
basic structural design has been incorporated in one or more
standardized package configurations in which the dimensions and
port configurations are largely pre-determined.
[0005] To monitor and provide electronic feedback regarding the
fuel oil pump unit, vacuum and pressure sensors may be incorporated
with the fuel oil pump unit upstream and downstream of the gear
pump. Incorporation of the sensors is problematic, however, because
the sensors must not alter the standardized package configuration
of the pump unit.
[0006] One solution to incorporating the pressure sensors into
existing standardized package configurations is provided in U.S.
application Ser. No. 10/461,152 assigned to the present assignee
and herein incorporated by reference in its entirety. The invention
disclosed in U.S. application Ser. No. 10/461,152 provides for an
additional outlet port disposed through the pump cover and
connected via a passageway to the nozzle outlet passage downstream
of the gear pump. A sensor attached to the additional outlet port
is therefore in fluid communication with downstream pressure
generated by the gear pump.
[0007] Since the passageway must pass through the pump cover and
pump body to communicate with the nozzle outlet passage, there
exists a potential for fuel leakage between the pump body and
cover. Specifically, because the passageway experiences a higher
pressure than the surrounding environment, fuel oil may be forced
along the mating surfaces of the pump body and pump cover and leak
or spray from the pump unit. This results in an extremely hazardous
condition where the leaked fuel may ignite causing an explosion. It
is therefore desirable to prevent such fuel leaks from
occurring.
SUMMARY OF THE INVENTION
[0008] The present invention prevents fuel leakage between the pump
cover and pump body by providing a gasket for placement
therebetween. The gasket, which may also seal the local reservoir,
is specially adapted to seal the passageway between the pump cover
and the pump body. To provide communication along the passageway
between the second outlet port and the nozzle outlet passage, the
gasket includes an aperture that aligns with the passageway.
Surrounding the aperture is a sealing ring of gasket material that
seals the passageway.
[0009] Because fuel oil may be forced through or around the sealing
ring, the gasket also includes a leakage collection channel
surrounding the aperture and spaced therefrom by the sealing ring.
The leakage collection channel is formed from a plurality of
straight legs generally set in the gasket in a generally U-shaped
arrangement. The collection channel is positioned between the
aperture and the outer periphery of the gasket and includes a first
leg and a second leg arranged so as to communicate with the low
pressure local reservoir upstream of the gear pump when the fuel
oil pump unit is assembled. Accordingly, any fuel oil forced past
the sealing ring will be collected in the leakage collection
channel and returned to the local reservoir.
[0010] An advantage of the present invention is that the gasket
enables downstream pressure to be communicated across the
passageway to the second outlet port. Another advantage is that
high pressure fuel oil in the passageway is substantially sealed
therein by a sealing ring. Another advantage of the present
invention is that fuel oil forced from the passageway is collected
into a leakage collection channel and returned to the low pressure
local reservoir. These and other advantages and features of the
present invention will be apparent from the detailed description
and accompanying drawings.
[0011] Other aspects, objectives and advantages of the invention
will become more apparent from the following detailed description
when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings incorporated in and forming a part
of the specification illustrate several aspects of the present
invention and, together with the description, serve to explain the
principles of the invention. In the drawings:
[0013] FIG. 1 is a schematic representation of a oil pump unit
incorporated in a oil pumping system for a furnace or boiler, in
accordance with a preferred embodiment of the present
invention;
[0014] FIG. 2 is a perspective view of the oil pump unit shown in
FIG. 1 as it is hooked up to a burner according to an embodiment of
the present invention;
[0015] FIG. 3 is a top view of the oil pump unit shown in FIG.
1;
[0016] FIG. 4 is a frontal view of the oil pump unit shown in FIG.
2;
[0017] FIG. 5 is a bottom view of the oil pump unit shown in FIGS.
2 and 4;
[0018] FIG. 6 is a cross section of FIG. 5 taken about line 6-6
with a different type of regulating valve shown in comparison to
FIG. 1;
[0019] FIG. 7 is a cross section of FIG. 4 taken about line
7-7;
[0020] FIG. 8 is an exploded view of an embodiment of a pump unit
employing a gasket between the pump body and pump cover;
[0021] FIG. 9 is a front elevational view of the gasket illustrated
in FIG. 8; and
[0022] FIG. 10 is a rear elevational view of a pump cover for use
with a pump unit employing a gasket of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0023] As shown in the drawings, the invention is embodied in a
fuel oil pump unit 10 of the type used to supply fuel to the
combustion chamber 11 of a burner such as might be incorporated
into a furnace or boiler. The unit 10 includes a gear pump 15 that
draws fuel oil or other suitable fuel from an oil supply such as a
tank 12 through an intake line 13.
[0024] The gear pump 15 is contained within a pump housing that is
comprised of a pump body 14 (preferably made of case iron) and a
pump cover 16 (preferably made of aluminum). The pump cover 16 is
bolted to the pump body 14. The gear pump 15 is illustrated as the
conventional crescent type and includes an inner gear 17 within the
housing that is attached to a drive shaft 18 and that is
eccentrically disposed with respect to an outer gear 19. A
crescent-shaped member 20 is disposed between the non-engaging
portions of the teeth on the gears for the purpose of sealing the
expanding fluid chambers defined by the gears from the contracting
fluid chambers in a well known manner.
[0025] The pump shaft 18 is journalled in the pump body 14 and is
sealed with respect thereto by an elastomeric sealing member which
herein is shown in the form of a lip seal 22. The lip seal 22 is
disposed within and seals off a lubrication chamber 23 in the
housing.
[0026] The pump 15 includes an inlet side that communicates with a
local fuel oil reservoir 26 that receives fuel oil from the main
oil supply or tank 12. The pump cover defines an inlet port 28 to
which the intake line 13 (often provided by copper tubing) from the
storage tank 12 may be connected. The local fuel oil reservoir 26
is defined in a chamber formed between the pump body 14 and the
pump cover 16. More specifically, the pump cover 16 includes a
front side 48 and a rearwardly extending sidewall 50 that spaces
the front side 48 forward of the pump body 14 and that encloses the
fuel reservoir 26.
[0027] A suitable strainer 30 may be located within the reservoir
26 between the inlet port 28 and the pump inlet 25 to filter the
fuel oil as it is drawn from the tank to the pump 15. The pump 15
pressurizes the fuel oil and outputs fuel into an outlet passage 32
along the downstream side of the pump 15. A bleed valve 33 may be
disposed along the outlet passage 32. The outlet passage 32
ultimately delivers fuel oil to a main regulating valve assembly 34
that serves to regulate the pressure of fuel oil and causes fuel
flow to the burner 36 to be of a substantially constant
pressure.
[0028] The regulating valve assembly 34 is located in the pump body
14 and serves to control the fuel flow from the outlet passage 32
to an outlet port 41 defined by the pump body 41. A fitting 39 may
be mounted into the outlet port 41 of the pump body 14. Copper
tubing 38 or other suitable conduit means is mounted to the fitting
39 to connect the outlet port 41 of the pump body 14 to the burner
36.
[0029] The fitting 39 also provides a valve seat 40 for the
regulating valve assembly 34. The valve seat 40 is adapted to be
closed by a spring biased hollow piston 42. The piston 42 is
slidably mounted in a pressure chamber 44 and is spring biased to
regulate fuel flow enter the chamber 44.
[0030] The opening and closing of the regulating valve assembly 34
is controlled with a solenoid valve 58 that is mounted to the top
side of the pump body 14. As shown herein, the solenoid valve 58 is
of the blocking type, but it alternatively may be of the bypassing
type or other suitable control arrangement. The solenoid valve 34
controls opening of the regulating valve assembly 34 (i.e., the
outlet port of valve assembly 34) to the outlet passage 32 upon
startup and controls closing of the regulating valve assembly 34
upon shut down. The solenoid valve 58 includes an electrical
control element 66 drives a movable valve element 62 between open
and closed states to cause pressure to build or be relieved such
that the spring biased piston 42 either opens or closes a bypass
passage 60 that recirculates fuel to either the tank 12 or local
reservoir 26.
[0031] The electric control element 66 may include a thermistor
providing a desired time delay for switching the solenoid valve
between states. Alternatively, an electronic control (not shown)
for the burn may provide the means to control activation of the
solenoid control element. In either event, a delay is typically
provided in order to provide sufficiently high pump speed and fuel
pressure; and also to allow the speed of the blower (not shown),
which is driven by the same shaft 18 as the pump 15 to be
sufficient to establish a good draft up the chimney 72 of the
burner 36.
[0032] The disclosed embodiment may also or alternatively include a
diaphragm valve 74 or other similar bypass mechanism arrange in
parallel circuit with the first bypass mechanism of the solenoid
valve 58 and/or the regulating valve assembly 34. in the disclosed
embodiment, the diaphragm valve serves as a redundant backup to the
solenoid valve 58 to better ensure the proper opening of the fuel
regulating valve assembly 34 at an appropriate time. Such a
redundant bypass arrangement is disclosed in patent application
Ser. No. 10/017,153 filed on Dec. 14, 2001. The diaphragm valve 74
causes the pump 15 to reach a high start-up rpm before the
regulating valve assembly 34 opens and causes the regulating valve
assembly to close after the pump 15 falls below a certain rpm upon
shutdown. The diaphragm valve 74 is adapted to open or close a
second return passage 81 leading back to the pump reservoir 26 (or
alternatively to the tank 12). To provide for proper operation of
the diaphragm valve, a cone valve 82 is arranged upstream of the
diaphragm valve to provide a restriction and pressure drop that
determines when the diaphragm valve 74 closes the second return
passage 81.
[0033] As long as the speed of the pump 15 is relatively low, the
diaphragm valve 74 remains open to prevent a build up of pressure
in the chamber 44 of the regulating valve assembly 34 sufficiently
such that the regulating valve assembly 34 remains closed via the
spring biased piston 42. However, as the pump speed increases, the
increased flow past the cone valve 82 causes a pressure
differential in the diaphragm valve to overcome the force of a
seeping and close the diaphragm valve causing all of the fuel flow
to flow from the pump 15 through the outlet passage of the pump
body 14 to the regulating valve assembly 34.
[0034] In the disclosed embodiment, the diaphragm valve 74 acts as
a back up for the solenoid valve 58 to better ensure that smoking
or soot production does not occur in the combustion chamber 11. The
regulating valve assembly 34 remains closed as long as either the
diaphragm valve 74 remains open or the solenoid valve 58 remains
closes, thereby causing the piston 41 to be wide open and cause
flow to bypass along bypass passage 60. The regulating valve
assembly 34 opens and outputs fuel to the furnace only after the
diaphragm valve 74 closes and the solenoid valve 58 opens. Once
this happens (which is typically very quickly), all of the fuel
flow is pumped by the gear pump 15 through the outlet passage 32
and the outlet port 41.
[0035] In accordance with the present invention, the oil pump unit
10 provides a port arrangement that substantially maintains size
package of prior solenoid type models, while also accommodating
inlet side and outlet side electronic pressure gauges 84, 86. As is
evident from the foregoing, one inlet port 28 is provide to receive
fuel from the tank 12, and one outlet port 41 is provided to output
pressurized fuel o the burner 36.
[0036] To accommodate the inlet side electronic pressure gauge 84
at least one additional inlet side port 88 is provide in the bottom
side of the pump body 14. The inlet side port 88 is constantly in
fluid communication with the local reservoir 26 and subject to the
pressure experienced in the local reservoir 26 upstream of the pump
15. As a result, the pressure experienced at the inlet side
pressure gauge 84 is the vacuum pressure that is upstream of the
pump 15. The inlet side pressure gauge 84 provides electronic
feedback representing sensed vacuum pressure on an electrical line
90 which may be transmitted via telephone lines or a wireless
transmitter to a remote location. Such data that is transmitted
over the electrical line 90 is indicative of whether the oil pump
unit 10 is properly operating.
[0037] To accommodate the outlet side electronic pressure gauge 86,
an outlet side port 92 is formed into the front side of the pump
cover 16. Because the pump cover 16 is upstream of the pump 15, a
formed passage 94 is provided though the pump cover 16 and the pump
body 14 that bypasses the reservoir 26 to be in direct fluid
communication with the outlet port 41 on the downstream side of the
pump 15 and downstream of the solenoid valve 58. With this
arrangement, the outlet side port 92 is in constant communication
with the pressure generated by the pump when the solenoid valve 58
is open. With the given arrangement, downstream of the solenoid
valve 58, the outlet side pressure gauge 86 will also indicate if
the solenoid valve and regulating valve assembly are properly
operating. The outlet side pressure gauge 86 is mounted into the
outlet side port 92 and provides electronic feedback on an
electrical line 96. The pressure gauge data on electrical line 96
may be transmitted on telephone lines or a wireless transmitter to
a remote location.
[0038] The data from the pressure gauges 84, 86 can be used at a
remote location to determine whether the oil pump unit 10 is
properly operating. If the data indicates a problem, a service
technician can be sent to maintenance, repair or replace the oil
pump unit 10. The source of the problem might also be indicated by
the gauges 84, 86 such that the service technician can anticipate
the solution and be prepared during a maintenance visit.
[0039] The illustrated pump unit 10 also provides a port
arrangement that is suitable for use with existing applications.
For purposes of orientation, and as shown in FIGS. 2-5, a front
side 98 of the fuel pump unit 10 is provide by the pump cover 16.
With this orientation, the pump unit 10 has a top side 99, a bottom
side 100, a right side 101, and a left side 102. The main fuel
inlet port 28 is provide along the right side 101 of the pump 10 in
the pump cover 16, and is in a conventional position to connect to
existing tank intake lines (e.g., such as intake line 13 as shown)
without additional plumbing. Likewise, the main fuel outlet port 41
is on the left side of the pump unit 10 in the pump body 14, and is
in a conventional position to connect to existing outlet passage
conduits (e.g., tubing 38) without additional plumbing. The inlet
side port 88 formed in the bottom side 100 (adjacent a return port
89 that provides an option of connecting to the tank 12) receives
the electronic inlet side pressure gauge 84. Because the solenoid
valve 58 occupies the top side of the pump body 14, the other
pressure gauge 86 is mounted into the front side 98 of the pump
unit 10 through the outlet side port 92 formed into the front side
of the pump cover 16. To accommodate the outlet side port 92 and
communicating pressure passage 94, the pump cover 16 may include a
raised boss or projection 105 to ensure sufficient material is
provided to form the port 92 and passage 94.
[0040] Illustrated in FIG. 7 is another embodiment of a fuel oil
pump unit 200 for supplying fuel to a combustion chamber of a
furnace or boiler. The configuration of the fuel oil pump unit 200
within the fuel system of a furnace or boiler is substantially
similar to the configuration of fuel pump 10 and related components
as illustrated in FIG. 1.
[0041] Referring to FIG. 8, the fuel oil pump unit 200 includes a
pump body 210 and a pump cover 212 that can be bolted together by a
plurality of bolts 214. To pump the fuel, a rotating gear pump 220
is incorporated with pump body 210 as described above. For mounting
the gear pump 220 and pump cover 212, the pump body 210 includes a
generally planer mounting face 216. The fuel pump may also include
a regulating valve assembly operated by a solenoid valve 222 for
controlling the fuel flow to an outlet port 224 formed in the pump
body 210 that communicates with the burner.
[0042] The pump 220 communicates with and intakes fuel from a local
fuel oil reservoir 228 that receives fuel oil from a main fuel oil
supply. The local reservoir 228 corresponds to a volume formed
between the pump body 210 and the pump cover 212 when they are
bolted together. To form the volume, the pump cover 212 includes a
front side 230 and a rearward extending peripheral wall 232 that
offsets the front side from the pump body 210. A plurality of bolt
slots 215 are provided within the pump cover 212 and disposed
through the peripheral wall 232 for accommodating the bolts 214.
The front side 230 and peripheral wall 232 thereby enclose the
local reservoir 228. To transfer fuel from the main fuel oil supply
to the local reservoir 228, the pump cover 212 includes an intake
port 234 to which an intake line can be connected. For filtering
fuel, a strainer 236 can be provided within the local reservoir
separating the intake port 234 from the pump 220.
[0043] To prevent fuel from leaking from the local reservoir 228,
the fuel pump 200 includes a gasket 240 located between the pump
body 210 and pump cover 212 for forming a seal when the two are
bolted together. As illustrated in FIG. 9, the gasket 240 can be
formed as a generally planer gasket sheet 242 having an outer
periphery 244 and an inner periphery 246. The gasket sheet 242 can
be made from any suitable material such as a foam material or
fiberboard.
[0044] The outer periphery 244 corresponds generally to the shape
and dimensions of the pump cover 212 and is thereby compressed
between the peripheral wall 232 and mounting face 216 when the fuel
pump 200 is assembled. In the illustrated embodiment, the outer
periphery and the pump cover are both generally rectangular in
shape. To accommodate the pump 220 and strainer 236 that protrude
from the mounting face 216, the inner periphery 246 forms an
opening that may fit around the strainer. In the illustrated
embodiment, the shape of the inner periphery 246 and the strainer
236 are circular.
[0045] To accommodate the bolts 214 used to hold the pump cover 212
and the pump body 210 together, the gasket sheet 242 can include a
plurality of bolt holes 250. In the embodiment illustrated in FIG.
9, wherein the pump cover 212 and outer periphery 244 are
rectangular in shape, the location of the bolt holes 250
corresponds to the four corners of the gasket sheet 242 and are
spaced radially outward from the inner periphery 246. The pattern
of bolt holes 250 thereby aligns with a plurality of threaded holes
218 disposed into the mounting face 216 as illustrated in FIG.
8.
[0046] Referring to FIG. 8, to accommodate the inlet side and
outlet side electronic pressure gages 280, 282 for providing feed
back from the fuel oil pump unit 200, as described above, the fuel
oil pump unit includes a second inlet side port 284 and a second
outlet side port 286. The second inlet side port 284 is disposed
through the bottom side of the pump body 210 and is in constant
fluid communication with the local reservoir 228 upstream of the
pump 220. The second outlet side port 286 is disposed through the
front side 230 of the pump cover 212 and communicates with the
first outlet port 224 in the pump body 210 by way of a passageway
290 through the pump cover and pump body. The second outlet side
port 286 is therefore upstream of the pump 220 in constant
communication with the pressure generated by the pump when the
solenoid valve 222 is open.
[0047] To allow fluid communication across the passageway 290, as
illustrated in FIGS. 8 and 9, the gasket includes an aperture 252
that corresponds to the location of the passageway. The aperture
252 is disposed through the gasket sheet 242 partway between the
outer periphery 244 and the inner periphery 246. Surrounding the
aperture 252 is a sealing ring 254 of gasket material that
functions to seal the passageway 290. As illustrated in FIG. 9,
with the circular inner periphery 246, the aperture 252 and sealing
ring 254 are located radially outward from the inner periphery
generally toward the bolt hole 250 in the corner.
[0048] Referring to FIG. 8, as will be appreciated by those of
skill in the art, because the passageway 290 is in fluid
communication with the downstream side of the pump 220, the
passageway will typically experience a higher pressure than the
upstream local reservoir 228. In fact, the passageway 290 may
experience a higher pressure than the environment surrounding the
fuel oil pump unit 200. The high pressure of the fuel in the
passageway will tend to force fuel from the passageway into the
sealing ring of gasket material at the location of the aperture and
toward the inner and outer peripheries. Fuel forced to the inner
periphery will be safely received in the low pressure local
reservoir. However, fuel forced to the outer periphery may leak or
spray from the fuel oil pump unit to the environment. In addition
to creating a messy fuel spill, the leaking fuel presents a
dangerous fire hazard especially around a burner or furnace.
[0049] Therefore, to prevent fuel from leaking to the outer
periphery, the gasket 240 includes a leakage collection channel 256
proximate to the aperture 252 for returning fuel to the local
reservoir. In the embodiment illustrated in FIG. 9, the collection
channel 256 is located between the aperture 252 and the outer
periphery 244 includes a first leg 258 and a second leg 259
interconnected by an intermediate portion 260. Each leg is
substantially straight and arranged so as to surround the aperture.
Accordingly, the collection channel is generally U-shaped with each
leg and the intermediate section forming a corner where they
intersect. The sealing ring 254 is formed by the gasket material
remaining between the collection channel 256 and the aperture
252.
[0050] Because of the straight shape of the legs and intermediate
portion, the sealing ring has a generally square outline that
effectively adds more gasket material between the aperture and the
collection channel, especially around the corners. The additional
material and square corners of the sealing ring also provides the
thin gasket sheet with added strength at a critical location that
may be subject to high fluid pressure and pressure fluctuations.
Referring to FIG. 8, it will also be appreciated that the increased
strength of the sealing ring 254 is advantageous when the
passageway 290 is disposed at a non-perpendicular angle to the
mounting face 216 or when the portion of the passageway in the pump
cover must be axially offset from the portion of the passageway in
the pump housing. Such alignments may be necessitated by the
arrangement of the other components of the fuel pump unit.
[0051] As illustrated, the intermediate portion 260 is located
between the aperture 252 and the outer periphery 244 with the first
and second legs 258, 259 extending towards the inner periphery 246.
The first and second legs 258, 259 may be parallel to each other
or, as illustrated in FIG. 9, may diverge from each other as they
extend from the intermediate portion 260. Accordingly, the corners
formed by the intersection of the intermediate portion and the legs
may appear as right angles or obtuse angles. The collection channel
256 may be disposed partially or completely through the gasket
sheet 242. As will be appreciated from FIG. 8, when the fuel oil
pump unit 200 is assembled the ends of the first and second legs
258, 259 will be in communication with the local reservoir 228.
Accordingly, any fuel leaking from the passageway 290 toward the
outer periphery 244 will encounter the collection channel 256 and
be returned via the first and second legs to the local reservoir.
Depending upon the precise dimensions of the cover plate 212 and
the local reservoir 228, the first leg 258 may be longer than the
second leg 259.
[0052] Referring to FIG. 8, as described above, to accommodate the
solenoid valve 222 the first outlet side passage 286 is disposed
through the pump cover 212 near the top of the pump cover.
Accordingly, the passageway 290 is disposed through the pump body
210 near the top of the pump body. To correctly position the
aperture 252 and collecting channel 256, in the embodiment
illustrated in FIG. 9, the gasket 240 can be configured into an
upper portion and a lower portion as well as a first side portion
and a second side portion. The rectangular gasket is thereby
arranged into an upper first quarter 262, an upper second quarter
264, a lower first quarter 266, and a lower second quarter 268. The
aperture 252 and collecting channel 256 are positioned in the upper
first quarter 262.
[0053] To simplify assembly of the fuel oil pump unit, the gasket
240 can include a second redundant aperture 270 and a second
redundant collecting channel 274 positioned in the upper second
quarter 264 and arranged to mirror the first aperture 252 and
collecting channel 264. Accordingly, the second redundant
collecting channel includes a first leg 276 and a second leg 277
that are interconnected by an intermediate portion 278, each of
which is substantially straight. The second redundant aperture 270
and second redundant collecting channel 274 can be spaced apart by
a second sealing ring 272 of gasket material. The gasket 240 is
therefore symmetrical enabling assembly of the fuel pump without
having to orient the first and second side portions of the gasket
with the pump body and pump cover.
[0054] In an embodiment, to ensure that the collecting channel
communicates with the local reservoir, grooves can be machined or
otherwise formed into the pump cover. Specifically, referring to
FIG. 10, the pump cover 212 includes a backside 292 offset from the
front side 230 and corresponding to the peripheral wall 232. As
illustrated, the bolt slots 215 are disposed through the backside
292. Formed into the backside 292 and offset to one side of the
passageway is a groove 294. The groove 294 is formed so as to
access the volume that defines the local reservoir. Referring to
FIG. 8, as will be appreciated, when the fuel pump is assembled,
the groove aligns with the shorter second leg 259 to complete fluid
communication between the collecting channel 256 and the local
reservoir 228.
[0055] All references, including publications, patent applications,
and patents cited herein are hereby incorporated by reference to
the same extent as if each reference were individually and
specifically indicated to be incorporated by reference and were set
forth in its entirely herein.
[0056] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the invention (especially in
the context of the following claims) is to be construed to cover
both the singular and the plural, unless otherwise indicated herein
or clearly contradicted by context. The terms "comprising,"
"having," "including," and "containing" are to be construed as
open-ended terms (i.e., meaning "including, but not limited to,")
unless otherwise noted. Recitation of ranges of values herein are
merely intended to serve as a shorthand method of referring
individually to each separate value falling within the range,
unless otherwise indicated herein, and each separate value is
incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein, is
intended merely to better illuminate the invention and does not
pose a limitation on the scope of the invention unless otherwise
claimed. No language in the specification should be construed as
indicating any non-claimed element as essential to the practice of
the invention.
[0057] Preferred embodiments of this invention are described
herein, including the best mode known to the inventors for carrying
out the invention. Variations of those preferred embodiments may
become apparent to those of ordinary skill in the art upon reading
the foregoing description. The inventors expect skilled artisans to
employ such variations as appropriate, and the inventors intend for
the invention to be practiced otherwise than as specifically
described herein. Accordingly, this invention includes all
modifications and equivalents of the subject matter recited in the
claims appended hereto as permitted by applicable law. Moreover,
any combination of the above-described elements in all possible
variations thereof is encompassed by the invention unless otherwise
indicated herein or otherwise clearly contradicted by context.
* * * * *