Note: Descriptions are shown in the official language in which they were submitted.
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BACI~GROUND OF THE INVENTION
The present invention relates generally to a fuel burner pumping
system having means for purging air from the system. More particularly, the
invention relates to a system in which such means includes an air purging
valve located within an outlet passage leading from a fuel pumpto a no~zle
passage so as to by-pass a fuel pressure control valve so that air fromthe
system is exhausted directly into the nozzlé~ passage
In one prior system of the foregoing type, fuel from a supply is
drawn through a line by a crescent gear pump and is fed under pressure into
the main chambe.r of a pressure control valve through an outlet passage
communicating between the pump and the chamberO From the main chamber, the
pressurized fuel flows through an outlet port into a passage communicating
with a burner nozzle or nozzlesO An air purging valve is disposed within a .
second outlet passage by-passing the main chamber outlet port so as to .
communicate directly with the nozzle passageO In this prior system, the air :
purging vaIve is spring-biased toward a closed position to shut off fuel flow ~ ~ -
through the second outlet passage when the pump is inoperative and the fuel `
pressure within the system is lower than the air pressure capable of being
generated by the pumpO To purge air from the system as the pump is started,
the valve opens after the fluid pressure in the system becomes sufficient to
overcome tne biasing for~.e of the springO The purging valve remains open as
long as the fluid pressure within the system is sufficient to overcome the
springO Accordingly, during normalcperation of the pump, fluid flows into the ~.
nozzle passage through both the outlet port of the main chamber and the second -
outlet passage.
Oil burner pumping systems of the foregoing broad general character .
are disclosed in United States Patents, 3,566,901; 3,446,232; 3,446,231; and ~.
3,446,230. Other systems having air purging means are disclosed in United
States Patents 3,273,513; 3,143,967; 2,931,314; 2,915,015; and 2,763,3360 .
S~AKI O~ n-~
The primary object of the present invention is to provide a new and
improved fuel burner pumping system of.the foregoing general character in .. :
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which the valve for purging air from the system outwardly through the nozzle
passage remains normally closed during the regular operation of the pump but
still may be opened when the pump initially is turned on for purging air from
the system.
A more detailed object is to achieve the foregoing in one embodiment
by constructing the air purging valve to be operable manually from oukside a
housing member of the pump for movement from a normally closed position
blocking the flow of fluid through the second outlet passage to an open po-
sition permitting air to flow through the second outlet passage and into the
nozzle passageO
The invention also resides in the provision of an air purg-
ing valve of the type which remains closed during normal operation of
a burner systèm in a system of the type employing a normally open
shut-off valve whlch closes to block the ~low of fuel through the
no~zle at the same time that the pump is shut off.
A further object is to construct a system of this latter type so that
the air purging valve opens automatically for air to be purged from the system
when the pump initially is turned on, the air purging valve thereafter
closing automatically once the system is purged of air.
A still further object is to provide in such a~system an automatic
air purging valve whlch eloses as the fuel pressure acting against the pres-
sure control valve approaches a ~agnitude sufficient to begin opening of the
control valveO
These and other objects and advantages of the present invention will
become more apparent from the following detailed description when taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DR~INGS
Figure 1 is a schematic illustration of a fuel burner pumping system
embodying the no~el features ~ the present inventionO
Figure 2 is a view of a portion of the system showing parts thereof
in moved positions.
Figure 3 is a schematic illustration of an alternative embodiment of
the present inventionO
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Figure 4 is an enlarged cross-sectional viaw oE a portion of the
system shown in Figure 30
:~ DETAILED DESCRIPTION OF
THE PREFE~RED EMBODIMENTS
As shown in the drawîngs for purposes of illustration, the present
invention is embodied in a fuel burner pumping system 10 of the type used
in supplying fuel oil to a heating unit (not shown) such as a furnace or
: boiler. Herein, the system is disclosed as used in a so~called one-pipe lift
installation wherein fuel is fed through a single line 11 leading from a
suitable source 13 to a fuel pump 14. It will be appreciated, however, that
with minor modifications, the present system also may be employed in other
types of installations
With reference to Figure 1, the fuel pump 14 is mounted within a
housing 15 and is of the crescent gear type including an inner gear 16 mounted
on a drive shaft 17 and eccentrically disposed with respect to an inter-
meshing outer gear 19, A crescent-shaped member 20 is disposed within 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 well-known fashionO An inlet 21 of the pump communicates through .
the housing wlth a reservoir 230 The latter is defined by an end cover 24
bolted to the housing and having an intake 25 to which the fuelline 11 is -.
connectedO A suitable strainer 26 located within the reservoir between the
intake and the pump inlet serves to filter the fuel as it is drawn ~rom the
supply into the pumpO Upon exiting the pump, the fuel flows through an outlet
27 into an .outlet passage 29 communicating with a control valve assembly 30 -~
which serves to regulate the pressure of the fuel flowing to a burner nozzle
or nozzles (not shown) so as to be substantially constantO
Herein, the control valve assembly 30 is located within the housing
15 and serves to control the pressure of fuel through an outIet port 31
communicating with a nozzle passage 33 which leads to the fuel burner noæzle
or nozzlesO The outlet port is deflned by a fitting 34 threaded into a bore ~`
35 in one end of the housing and the fitting has a projection 36 defin~ng a
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valve seat adapted to be closed by the control valve 300
More particularly, the control valve assembly includes a main pressure
chamber 37 communicating with the pump outlet passage 29. A hollow valve
member 39 is slidably mounted within the main pressure chamber and includes a
land 40 disposed centrally between opposite ends of the valve memberO Affixed
; within an undercut recess in the forward end of the valve member is a valve
closure 41 adapted to engage the valve seat 36 and close the outlet port 310
In operation, high pressure fuel entering the main pressure chamber
31 from the pump 14 moves the valve member 39 to the right against the closing
force of a coil compression spring 43 seated within the hollow portion of the
valve member and reacting against a normally stationary, but adjustable spring
seat 440 When the pressure in the chamber is sufficiant to overcome the clo-
sing force of the spring, the valve member will move to the right, opening the
. outlet port and permitting fuel to flow into the nozzle passage 33. Only a
portion of the fuel from the outlet passage 29 of the pump exits the control -
valve 30 through the outlet port 31, the remaining portion by-passes the out- :
let port and exits the main pressure chamber through a return port 45 opening
into a return passage 46 leading back to the reservoir 230 In normal opera- ;
: tion9 the fuel flow from the pump 14 is sufficient to move the valve member 39 ` .
to the right far enough for the land 40 to uncover the return port 45 so fuel
continuously passes into the return passage while the valve member, in con-
junction with the spring 43, modulates a constant pressure fuel flow through
the outlet port 31 into the nozzle passage 33.
As shown in Figure 1, the return passage 46 communicates with a
shaft seal assembly 47 located within the housing and serving to keep fuel from
- leaking along the drive shaft 17 and out of the housing 150 In parti.cular,
the seal assembly includes a sealing member 49 engaging the drive shaft between
i the outside of the housing and a collection chamber 50 within which fuel
flowing along the shaft accumulates and is kept from flowing out of the housing~ -
From the collection chamber, the passage 46 leads bacX to the reservoir 23
returning both the excess fuel from the main pressure chamber 30 and the
leakage fuel from along the shaftO In other types of installations, the return ~.
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. passage may connect directly with the fuel supply source 130
: In the exemplary fuel pumping system 10, in order to purge air from
the pump 14 as the latter initially is started, a second outlet passage 51 is
located between the pump and the nozzle passage 33 to by-pass the control
valve assem~ly 30 for exhausting air and mixed fuel and air into the nozzle
passage instead of having to drain and collect this mixture in a special
containerO As the pump is started, an air purging valve 53 in this outlet
passage may be opened so that air trapped within the pump may be exhausted
from the system without creating a~mess outside of the heating unit~
The present invention contemplates an improved fuel pumping system
lO in which the air purging valve 53 remains closed during normal operation
of the pump 14 so as to keep fuel from flowing through the second outlet
passage 51 and into the nozzle passage 33 after the system is purged of air.
For this purpose, valve means defining the air purging valve 53 are constructed
- in a novel fashion and include a movable valve body 54 normally held in a
closed position to block the flow of fuel through the second outlet passageO
.~ But, when the pump initially is started, the valve body may be moved into an
open position permitting air to be purged from the system, the fuel flowing
through the second outlet passage and into the nozzle passage. Once air is
purged from the system, the valve is closed and remains closed throughout
the normal operation of the pumpO By virtue of this arrangement, high pressure
fuel is kspt`-from flowing through the second outlet passaga and into the
noz71e passage during normal operation of the pump so as to avoid interfering :
with the regulated flow of fuel entering the nozzle passage from the outlet
port 31 of the main pressure chamber 37
In one form o~ the present invention ~shown in Figures land 2),
the air purging valve means 53 is in the form of a manually operable valve
including the valve body 54 with means connected thereto for moving the valve
body between open and closed positions within the second outlet passage 510 ..
Herein, such connecting means is in the form of an elongated stem 55 integrally --
connected to the valve body and extending outwardly through a bore 56 formed ~-
in the housing 15 for connection with a handle 570 The handle is pivotally
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connected to the outer end portion of the stem by a pin 59 between a nut 60
threaded on the outer end of the stem and a fitting 61 threaded into a counter
bore 63 formed in the housing. A recess 64 in the inner end of the fitting
receives a spring 65 telescoped on to the stem between the bottom of the
recess and a shoulder 66 formed intermediate the ends of the stem. The
spring is of sufficient strength to urge the valve stem inwardly so the valve
body 54 is held against a sui-table seat 67 to block the flow ~ fuel through the
second outlet passage under the high fuel pressures generated by normal
operation of the pump 140 To keep fuel from leaking along the stem and out
10 of the housing, an O-ring seal 69 seated within an annular groove 70 formed -
in the shoulder engages the sides of the bore 56.
In the foregoing described embodiment of the exemplary pumping system
: 10, to purge air from the system when the pump 14 is started, the handle 57
is pulled outwardly (see Figure 2) with one end 71 of the handle levering
- against the fitting 61 so the stem 55 is pulled outwardly by the pin 59. The
stem, in turn, pulls the valve body 54 away from its seat 57, thereby opening
the second outlet passage 51 to permit air to flow through such passage and
:: into the nozzle passage 330 Thus, the air trapped in the pump may be easily
vented from the systemO Once the air is vqnted from the system, the handle
is simply released to allow the spring 65 to urge the valve body back against
the seat to close off the secand outlet passageO
- A second form of the present invention is shown in Figures 3 and 4,
; wherein parts corresponding to those described in the first embodiment are
identlfied by the same but primed reference numberO In the second form of
. the fuel pumping system 10', a suitable shut-off valve means 71, such a con-
ventional solenoid valve, is located within the nozæle passage 33' between the
burner nozzle and the opening of the second outlet passage 51' into the nozzle
passageO Preferably, the shut-off valve is operable in conjunction with a ;~
thermostat (not shown) controlling operation of the pump 14' so that, as the
pump is turned on and off, the shut- off valve is opened and closed to control
the flow of fuel to the nozzle~ With such a valve in the system, when the pump
is turned on, the shut-off valve is opened, permitting fuel flow to the nozzle,
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but, at the same time that the pump is turned off, the valve closes, blocking
fuel flow to the burner nozzleO
Advantageously, in this latter form of the exemplary pumping system,
the air purging valve means 53' is operable automatically to purge the system
of air as the pump 14' is started, while still serving to block the flow of
fuel through the second outlet passage ~1' as the magnitude of the fuel
~ pressure in the system builds toward normal values. As shown in Figure 4, the
- automatic air purging valve is bolted to the housing 15' along with the
crescent gear pump 14' and is located within the reservoir 23'. More partic-
10 ularly, the valve body 54' is inthe form of a generally cylindrical plunger
which is connected to fluid pressure responsive means for urgingthe body into
its closed position as the output fluid pressure from the pump approaches ;,:
a magnitude to begin opening the control valve 30'. Preferably, the fluid
pressure responsive means is in the form of a flexible diaphragm 73O The
plunger includes an annular flange 74 si ed to engage tXe valve seat 67lo
Herein, the plunger is located within an operating chamber 75 having inlet and
outlet ports 76 and 77 communicating with the second outlet passage 51' so
that fuel pumped through the outlet passage necessarily flows through the
, operating chamberO The diaphragm extends across the outer end of the operating
chamber and includes inner and outer faces 79 and 80 communicating directly
with the operating chamber and the reservoir, respectively. Urging the ~ .
plunger and the diaphragm inwardly is a spring 81 having an inner end
connected to the outer end of the plunger and an outer end seated against an :
outwardly extending projection of a cap plate 83. The latter is secured to
a block member 84 within which is formed the operating chamber 75, the
diaphragm be~ng sandwiched between the plate and the block memberO
`~ Preferably, the strength of the spring 81 is such as to move the .
plunger 54' inwardly until the inner end of the plunger engages the inner
wall 85 of the operating chamber (see Figure 4) when the magnitude of the fuel `.
pressure within the operating chamber is less than approximately twenty-five ;
percent of the normal operating pressure of the system, thereby opening the . : :
purging valve 53' to allow air to be exhausted from the system through the .
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second outlet passage 51' and nozzle passage 33'. Advantageously, this means
that every time the pump is started,when the system pressure has dropped below
twenty-five percent of the normal operating fuel pressure, any air in the : :
; system is exhausted automatically through the second outlet passage and into
the nozzle passageO As the pump 14' begins to build up Eluid pressure ~ excess
of the valve opening pressure, the fluid pressure in the operating chamber 75
pushes the diaphragm 73 outwardly, thereby pulling the plunger 54' away from ~:
the inner wall of the chamber and closing the flange 74 against the valve
seat 67' to block the flow of fluid through the operating chamber. By virtue
of operating in this fashion, it will be appreciated that the air purging
valve remains closed during normal operation of the pump to keep fuel from
flowing into the noz7.1e passage from the second outlet passage and interfering .
with the regulated flow of fuel from the main pressure chamber 37~O
Thus, it is seen from the foregoing tha~ the present invention
brings to the art a new and improved fuel pumping system 10 wherein fuel is
kept from by-passing the control valve assembly 30 during normal operation of .;
the pump 14 while still enabling air to be purged easily from the system when ~:
the pump is startedO In one form of the invention, this is accomplished through
the provision of a unique, manually-operated air purging valve 53, which is :
spring urged into a closed position to block fuel flow through the second
outlet passage 51 during normal operation of the pump, but is movable manually
- into an open position when it is desired to purge air from the system~ In
another form of the invention, an automatic air purging valve 53' serves to .
purge air from the system initially as the pump 14' is started, but as the
pressure in the system begins to approach normal operating magnitudes, the
valve is closed and remains closed during normal operation of the pumpO .
