Information
-
Patent Grant
-
6450152
-
Patent Number
6,450,152
-
Date Filed
Friday, June 15, 200123 years ago
-
Date Issued
Tuesday, September 17, 200221 years ago
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Inventors
-
Original Assignees
-
Examiners
-
CPC
-
US Classifications
Field of Search
US
- 251 12921
- 123 516
- 123 518
- 123 519
- 123 520
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International Classifications
-
Abstract
A low-profile tank isolation valve mounts on a wall of a fuel tank to enclose an opening in the tank wall through which an inlet port of the valve is communicated to tank headspace. An electric actuator is selectively energized to selectively operate an armature to cause a closure to seat on, and unseat from, a valve seat. The armature is a cylindrical walled tube that is disposed within a central through-hole of the actuator and is selectively positioned along a straight axis coincident with the tube axis. An element that operatively relates the armature to the closure constrains vapor flow through the valve to pass through the armature tube when the closure is unseated. The seat, closure, and element are all disposed within the actuator through-hole.
Description
FIELD OF THE INVENTION
This invention relates generally to a fuel vapor management system for a motor vehicle that is powered by an internal combustion engine and more particularly to a valve for isolating headspace of a fuel tank from a vapor storage canister.
BACKGROUND OF THE INVENTION
A known on-board fuel vapor management system for an automotive vehicle comprises a vapor storage canister that collects volatile fuel vapors generated in headspace of a fuel tank by the volatilization of liquid fuel in the tank and a purge valve for periodically purging collected vapors from the canister to an intake system of the engine. A known type of purge valve, sometimes called a canister purge solenoid (or CPS) valve, comprises a solenoid actuator that is under the control of a microprocessor-based engine management system.
During conditions conducive to purging, the canister is purged of collected fuel vapors by communicating the canister to the engine intake system through the CPS valve. The CPS valve is opened by a signal from an engine management computer in an amount that allows intake manifold vacuum to draw volatile fuel vapors from the canister for entrainment with the combustible mixture passing into the engine's combustion chamber space at a rate consistent with engine operation to provide both acceptable vehicle driveability and an acceptable level of exhaust emissions.
It is desirable to vent the canister to atmosphere to allow stored vapors to be more efficiently purged to the engine. It is known to communicate a vent port of a canister through a vent valve to atmosphere. The vent valve may be opened during certain conditions, such as during purging of the canister, and closed during other conditions, such as during a leak detection test.
In certain vapor management systems, the fuel tank headspace is in continuous communication with the canister. Other systems may call for the canister to be isolated from the tank headspace during certain conditions, in which case, the system may further comprise a tank isolation valve that, when open, allows free communication between the tank headspace so that vapors can pass from the tank to the canister, and that, when closed, disallows free communication to isolate the tank headspace from the canister.
It is known to mount such an isolation valve in a generally vertical orientation and at a location in a vehicle that is remote from the fuel tank.
SUMMARY OF THE INVENTION
It is believed that a tank isolation valve that can be mounted directly on a fuel tank and in a generally vertical orientation can provide certain benefits in the design of an automotive vehicle fuel system and associated vapor management system, especially if the valve is more vertically compact, and/or is capable of being partially disposed within the interior of a fuel tank. An isolation valve that is more vertically compact and/or capable of being partially disposed within a depression in a tank wall can present a lower external profile when the tank and valve are viewed in vertical elevation. It is believed that such a lower profile can be useful to vehicle designers in packaging various components of the vehicle in and adjacent the fuel tank.
Principles of the invention, as disclosed herein, provide a low-profile tank isolation valve possessing these attributes and capabilities.
In one general respect, the present invention relates to a fuel vapor management system for an internal combustion engine fuel system wherein fuel vapor generated by the volatization of fuel in a fuel tank is collected in a vapor storage canister that is purged to the engine during conditions conducive to purging. Headspace of the fuel tank is selectively communicated to the vapor storage canister through a tank isolation valve. When open, the valve allows free communication between the tank headspace and the canister so that volatile vapor can pass from the tank to the canister, and when closed, the valve disallows free communication to thereby isolate the tank headspace from the canister.
The valve comprises a body mounted on a wall of the tank in enclosing relation to an opening in the tank wall. The valve has an inlet port communicated to the tank headspace at the tank wall opening, an outlet port, and a flow passage through which vapor entering the inlet port from the headspace can be conveyed to the outlet port. A valve seat circumscribes the flow passage, and a closure selectively seats on, and unseats from, the valve seat to selectively close, and open, the flow passage. An operating mechanism comprises an electric actuator that is selectively energized by electric current and an armature that is selectively positioned by the selective energization of the actuator to selectively operate the closure to seat on, and unseat from, the valve seat. An element that is disposed between the armature and the closure operatively relates the armature to the closure. The armature comprises a cylindrical walled tube that is open at opposite axial ends and is selectively positioned within the body along a straight axis coincident with the tube axis. The element constrains vapor flowing through the flow passage to pass through the armature tube when the closure is unseated from the seat.
In another respect, the present invention relates to a valve, as just described, for venting tank headspace.
In another general respect, the present invention relates to a fuel vapor management system as defined above wherein the tank isolation valve comprises an inlet port communicated to the tank headspace at the tank wall opening, an outlet port, and a flow passage through which vapor entering the inlet port from the headspace can be conveyed to the outlet port. A valve seat circumscribes the flow passage, and a closure selectively seats on, and unseats from, the valve seat to selectively close, and open, the flow passage. An operating mechanism comprises an electromagnet coil that is selectively energized by electric current to selectively position an armature coaxially with respect to a central through-hole of the coil to cause the closure to seat on, and unseat from, the valve seat. The seat and the closure are disposed within the coil through-hole, and the armature comprises a through-passage having opposite ends, one of which is disposed within the through-hole and is toward the closure and the other of which is toward one of the ports, to provide for vapor that passes from the inlet port to the outlet port when the closure is unseated from seat to pass through the through-passage in the armature.
In another respect, the present invention relates to a valve, as described in the immediately preceding paragraph, for venting tank headspace.
Additional aspects of the invention relate to various constructional details of the valve.
The foregoing, along with additional features, advantages, and benefits of the invention, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a presently preferred embodiment of the invention according to the best mode contemplated at this time for carrying out the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
a longitudinal cross-sectional view, in elevation, through a valve embodying principles of the invention, and includes a portion of a fuel tank on which the valve is mounted.
FIG. 2
is an elevation view, not in cross section, of a fragmentary portion of the valve relevant to its mounting on the fuel tank.
FIG. 3
is view of
FIG. 1
with the valve removed to show detail of locking features on the tank relevant to the valve mounting.
FIG. 4
is fragmentary view, partly in cross section, showing the valve locked on the tank by the tank locking features.
FIG. 5
is view like
FIG. 2
showing a modified mounting.
FIG. 6
is a fragmentary view illustrating a modified internal mechanism of the valve.
FIG. 7
is a fragmentary view illustrating another modified internal mechanism of the valve.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
shows an exemplary embodiment of tank isolation valve
10
according to the present invention for selectively communicating headspace of a motor vehicle fuel tank to a vapor storage canister. Valve
10
comprises a body
12
having an inlet port
14
adapted to be communicated to the tank headspace, an outlet port
16
, and a flow passage
18
extending between the two ports.
A valve seat
20
circumscribes passage
18
interiorly of, and proximate, inlet port
14
. A closure
22
is disposed for selectively seating on, and unseating from, seat
20
to selectively close, and open, passage
18
.
FIG. 1
shows valve
10
open with closure
22
unseated from seat
20
.
An operating mechanism
24
for operating closure
22
comprises an electric actuator
26
that is selectively energized by electric current. An armature
28
is selectively positioned by the selective energization of actuator
26
to selectively operate closure
22
to seat on, and unseat from, seat
20
. An element
30
is disposed between armature
28
and closure
22
to operatively relate the armature to the closure.
Armature
28
comprises a circular cylindrical walled ferromagnetic tube that is open at opposite axial ends and is selectively positioned by operating mechanism
24
within body
12
along a straight axis
32
coincident with the tube axis. One axial end of the tube is toward outlet port
16
while the other axial end is toward closure
22
. The tube wall circumscribes a circular cylindrical through-passage
34
that extends between axial ends of the tube.
Element
30
is preferably fit to the one axial end of the armature tube that is toward closure
22
in covering relation to through-passage
34
, but comprises at least one through-opening
36
that is open to the through-passage. With closure
22
unseated from seat
20
, element
30
constrains flow that has entered inlet port
14
and has passed the unseated closure to pass through through-passage
34
before reaching outlet port
16
and exiting valve
10
. Element
30
comprises a cylindrical body having a shouldered perimeter rim seating the element on the one axial end of the armature tube, and a post
38
that extends from a central region of the body of the element toward closure
22
for operatively relating the element to the closure.
Closure
22
comprises a cylindrical body having a central region joining with a distal end of post
38
to join element
30
and closure
22
for motion in unison. The central region of the closure body and the distal end of post
38
join together at a joint that allows closure
22
to tilt slightly on post
38
for compliant seating on valve seat
20
.
Operating mechanism
24
further comprises a spring
40
that resiliently biases element
30
and closure
22
away from inlet port
14
and hence away from seating on seat
20
.
Actuator
26
comprises an electromagnet coil
42
disposed about a central through-hole
44
that is concentric with axis
32
and hence with the armature tube. A stator
46
is associated with coil
42
to form a solenoid assembly with the stator conducting magnetic flux across an air gap
48
to act on armature
28
. Stator
46
comprises two ferromagnetic parts, namely a cup
50
and a cap
52
, that cooperate to enclose coil
42
, except where electric terminals
54
pass through cap
52
to provide for coil
42
to be connected to an external electric circuit (not shown) for operating the coil.
Body
12
comprises two individual parts
56
,
58
assembled together. Part
56
comprises a plastic shell having a circular cylindrical shape. Part
58
comprises a circular plastic cover that carries terminals
54
. The two parts fit together at a sealed joint to capture and enclose the solenoid assembly and to associate terminals
54
with coil
42
. Catches
60
on one of the parts catch an overhang on the other of the parts at the joint to secure the parts to each other, and sealing is provided by an O-ring
62
disposed in a circular groove in one of the two parts. Inlet port
14
and valve seat
20
are formed integrally with part
56
. Inlet port
14
comprises an integral tubular nipple of part
56
extending outward of the interior of body
12
from a bottom end wall of part
56
with its centerline concentric with axis
32
. Interiorly of body
12
, a circular cylindrical riser
64
continues as an inward extension of inlet port
14
. Riser
64
extends into through-hole
44
with its end edge surface forming seat
20
. In this way seat
20
is disposed within through-hole
44
. Element
30
and closure
22
are also disposed within through-hole
44
. Outlet port
16
is formed integrally with part
58
as a tubular nipple that extends radially outward beyond the joint between the two parts
56
,
58
. A connector shell for terminals
54
is also integrally formed with part
58
.
Spring
40
comprises a helical coil one end of which seats on the portion of the bottom end wall of part
56
that surrounds riser
64
and the opposite end of which seats against the outer margin of closure
22
. While the portion of closure
22
bounded by its outer margin is imperforate, the portion that comprises the outer margin contains circumferentially spaced apart notches
66
. In this way the imperforate portion of the closure will obturate passage
18
when the closure is seated on seat
20
, but once the closure has unseated, vapor can pass from inlet port
14
across seat
20
and through notches
66
on its way to outlet port
16
. To assure vapor-tight seating of the closure on seat
20
, it may be desirable to apply a circular seal
68
of any suitable material to the portion of closure
22
that seats on seat
20
.
FIG. 1
shows valve
10
in a condition where coil
42
is not being energized. Spring
40
is biasing the assembly consisting of closure
22
, element
34
, and armature
28
away from inlet port
14
to cause the end of armature
28
opposite element
34
to abut a stop
68
. Stop
68
comprises several posts that extend downward into the interior of body
12
from a wall of cover
58
directly above armature
28
. The posts are spaced apart from each other to provide free communication of through-passage
34
to outlet port
16
when armature
28
is abutting stop
68
.
Part
56
comprises features on the exterior of its side wall that provide for secure mounting on a wall of a fuel tank. Those features are shown in the fragmentary view of
FIG. 2. A
circular flange
70
girdles the side wall and supports four identical upright locking elements
72
spaced uniformly around, and a short distance from, the side wall. Each locking element comprises an upper edge that begins with an inclined ramp
74
and ends in a locking barb
76
. The locking elements are adapted for cooperation with features on a fuel tank to provide a twist lock mounting of valve
10
on the tank.
FIG. 3
shows a portion of a top horizontal wall
78
of a fuel tank. Four identical catches
80
having open throats
82
are spaced uniformly on the exterior of wall
78
around the rim of a depressed receptacle
79
in wall
78
. The bottom of the receptacle has an circular hole that allows inlet port
14
to be disposed in the tank headspace for placing the inlet port in communication with the tank headspace. Valve
10
mounts on the tank by aligning it to the receptacle with locking elements
72
out of circumferential registration with catches
80
, and then advancing it toward the tank until flange
70
abuts the receptacle rim at wall
78
. The valve is then turned to cause each locking element
72
to enter the open throat
82
of a respective catch
80
. As ramps
74
ride across leads
84
at the free ends of the catches, the catches flex. When barbs
76
arrive at holes
86
in the catches immediately proximal to leads
84
, the catches relax, causing the barbs to lodge to the holes and thereby lock the valve in the receptacle as shown by FIG.
4
.
The mounted valve is suitably sealed to the tank wall to prevent leakage between the valve body and the receptacle hole. Receptacle
79
may be shaped with a shoulder that forms a neck
87
to which an O-ring
88
on inlet port
14
can seal. A gasket
89
may be provided between flange
70
and the rim of the receptacle.
FIG. 1
shows flange
70
disposed approximately at mid-height of valve body
12
so that when the valve is mounted in the depressed receptacle, only an upper portion of the valve protrudes from the receptacle.
FIG. 5
shows an alternate arrangement where flange
70
is close to the bottom of the valve body so that the overall profile will be higher. An appropriate change is made to the shape of the tank receptacle for the valve. Flange
70
may optionally have holes to provide for mounting by means of fasteners, rather than use of the twist-lock feature. Such a fastener alternative provides one way for allowing valve
10
to be mounted remote from the tank, in which case inlet port
14
may be communicated to the tank headspace via a hose, or conduit. Another conduit is also present to communicate outlet port
16
to the canister in all embodiments.
FIG. 6
shows a modified form for closure
22
and element
30
. Rather than directly attaching closure
22
to the distal end of post
38
, closure
22
has a depression
90
at its center, and post
38
has a rounded end that fits into the depression. This enables closure
22
to tilt on the post and provide for compliance of closure
22
to seat
20
.
FIG. 7
shows another modified form for closure
22
and element
30
. Here the closure and element are formed as a single part, and the notched outer rim of closure
22
is eliminated so that spring
40
fits over it to seat on the outer rim of element
30
. Because closure
22
and element
30
are a single part that is relatively rigid, it may be desirable to apply a circular seal
68
suitable material to the portion of closure
22
that seats on seat
20
to secure compliant seating.
The valve of the present invention possesses a low vertical profile because seat
20
, closure
22
, element
30
and most of armature
28
are disposed within the central through-hole
44
in the armature. The overall profile of valve and tank is lowered even more by providing a depressed receptacle in the top wall of the tank as described. Use of a cylindrical tube for the armature and venting through the tube provides a substantial transverse cross section for the flow area in relation to the diameter of the through-hole in the actuator. Although not specifically shown, the armature is guided in any suitable manner that avoids shorting of the air gap by the armature.
While a presently preferred embodiment of the invention has been illustrated and described, it should be appreciated that principles are applicable to other embodiments that fall within the scope of the following claims.
Claims
- 1. A fuel vapor management system for an internal combustion engine fuel system wherein fuel vapor generated by the volatization of fuel in a fuel tank is collected in a vapor storage canister that is purged to the engine during conditions conducive to purging, and headspace of the fuel tank is selectively communicated to the vapor storage canister through a tank isolation valve that comprises a valve body and that when open, allows free communication between the tank headspace and the canister so that volatile vapor can pass from the tank to the canister, and when closed, disallows free communication to thereby isolate the tank headspace from the canister, the system comprising:an opening in a wall of the tank on which the body of the valve is mounted in enclosing relation to the opening; the valve further comprising an inlet port communicated to the tank headspace at the opening, an outlet port, and a flow passage through which vapor entering the inlet port from the headspace can be conveyed to the outlet port; a valve seat circumscribing the flow passage; a closure for selectively seating on, and unseating from, the valve seat to selectively close, and open, the flow passage; an operating mechanism comprising an electric actuator that is selectively energized by electric current and an armature that is selectively positioned by the selective energization of the actuator to selectively operate the closure to seat on, and unseat from, the valve seat; an element that is disposed between the armature and the closure to operatively relate the armature to the closure; wherein the armature comprises a cylindrical walled tube that is open at opposite axial ends and is selectively positioned within the body along a straight axis coincident with the tube axis, and the element constrains vapor flowing through the flow passage to pass through the armature tube when the closure is unseated from the seat.
- 2. A system as set forth in claim 1 in which the element is fit to the tube at the one axial end of the tube and comprises at least one through-opening through which vapor can pass into the tube.
- 3. A system as set forth in claim 2 wherein the element comprises a cylindrical body having a shouldered perimeter rim seating the element on the one axial end of the tube, and a post that extends from a central region of the body of the element toward the closure for operatively relating the element to the closure.
- 4. A system as set forth in claim 3 wherein the closure comprises a cylindrical body having a central region joining with a distal end of the post to join the element and the closure for motion in unison, and the central region of the closure body and the distal end of the post join together at a joint that allows the closure to tilt slightly on the post for compliant seating on the valve seat.
- 5. A system as set forth in claim 3 wherein the operating mechanism comprises a spring that resiliently biases the element and the closure away from seating on the valve seat, the valve seat is disposed proximate the inlet port and, the spring acts to bias the element and the closure away from the inlet port.
- 6. A system as set forth in claim 3 wherein the operating mechanism comprises a spring, and the closure comprises a cylindrical body that is resiliently biased by the spring away from seating on the valve seat and that has a central region biased against a distal end of the post so as to allow the closure to tilt slightly relative to the post for compliant seating on the valve seat.
- 7. A system as set forth in claim 6 wherein the actuator comprises an electromagnet coil disposed about a central through-hole with respect to which the armature tube is selectively coaxially positioned, the valve seat is disposed within the through-hole, and when the closure is seated on the seat, the element and the closure are also disposed within the through-hole.
- 8. A system as set forth in claim 1 wherein the top wall of the tank comprises a depressed receptacle containing the opening, and the valve body fits into the receptacle so that only an upper portion of the valve body protrudes out of the receptacle.
- 9. A fuel vapor management system for an internal combustion engine fuel system wherein fuel vapor generated by the volatization of fuel in a fuel tank is collected in a vapor storage canister that is purged to the engine during conditions conducive to purging, and headspace of the fuel tank is selectively communicated to the vapor storage canister through a tank isolation valve that comprises a valve body and that when open, allows free communication between the tank headspace and the canister so that volatile vapor can pass from the tank to the canister, and when closed, disallows free communication to thereby isolate the tank headspace from the canister, the system comprising:an opening in a wall of the tank on which the body of the valve is mounted in enclosing relation to the opening; the valve further comprising an inlet port communicated to the tank headspace at the opening, an outlet port, and a flow passage through which vapor entering the inlet port from the headspace can be conveyed to the outlet port; a valve seat circumscribing the flow passage; a closure for selectively seating on, and unseating from, the valve seat to selectively close, and open, the flow passage; an operating mechanism comprising an electromagnet coil that is disposed about a central through-hole and is selectively energized by electric current to selectively position an armature coaxially with respect to the central through-hole to cause the closure to seat on, and unseat from, the valve seat; wherein the seat and the closure are disposed within the central through-hole, and the armature comprises a through-passage having opposite ends, one of which is disposed within the through-hole and is toward the closure and the other of which is toward one of the ports, to provide for gases that pass from the inlet port to the outlet port when the closure is unseated from the seat to pass through the armature through-passage.
- 10. A system as set forth in claim 9 including an element that is fit to the armature at the one end thereof and comprises at least one through-opening through which vapor enters the through-passage after having passed the unseated closure.
- 11. A system as set forth in claim 9 wherein the seat is disposed at a distal end of a riser that is disposed on a wall of the valve body in circumscribing relation to the flow passage.
- 12. A system as set forth in claim 11 wherein the seat comprises a surface of the riser.
- 13. A system as set forth in claim 8 wherein the top wall of the tank comprises a depressed receptacle containing the opening, and the valve body fits into the receptacle so that only an upper portion of the valve body protrudes out of the receptacle.
- 14. A valve for selectively venting headspace of a fuel tank in an automotive vehicle having an engine that is powered by volatile fuel stored in the tank, the valve comprising:a body having an inlet port adapted to be communicated to the tank headspace, an outlet port, and a vent passage between the ports; a valve seat circumscribing the passage; a closure for selectively seating on, and unseating from, the seat to selectively close, and open, the passage; an operating mechanism comprising an electric actuator that is selectively energized by electric current and an armature that is selectively positioned by the selective energization of the actuator to selectively operate the closure to seat on, and unseat from, the seat; wherein the armature comprises a through-passage having opposite ends, one of which is toward the closure and the other of which is toward one of the ports; and an element that is disposed between the armature and the closure to operatively relate the armature to the closure and that, when the closure is unseated from the seat, constrains flow between the ports to pass through the through-passage in the armature.
- 15. A valve as set forth in claim 14 wherein the armature comprises a cylindrical walled tube that is open at opposite axial ends and is selectively positioned within the body along a straight axis coincident with the tube axis, one axial end of the tube being toward the one port and the other axial end being toward the closure, and the through-passage extends between the axial ends of the tube and is circumscribed by the wall of the tube.
- 16. A valve as set forth in claim 15 in which the element is fit to the tube at the one axial end of the through-passage and comprises at least one through-opening that is open to the through-passage.
- 17. A valve as set forth in claim 16 wherein the element comprises a cylindrical body having a shouldered perimeter rim seating the element on the one axial end of the tube, and a post that extends from a central region of the body of the element toward the closure for operatively relating the element to the closure.
- 18. A valve as set forth in claim 17 wherein the closure comprises a cylindrical body having a central region joining with a distal end of the post to join the element and the closure for motion in unison.
- 19. A valve as set forth in claim 18 wherein the central region of the closure body and the distal end of the post join together at a joint that allows the closure to tilt slightly on the post for compliant seating on the valve seat.
- 20. A valve as set forth in claim 17 wherein the operating mechanism comprises a spring that resiliently biases the element and the closure away from seating on the valve seat.
- 21. A valve as set forth in claim 20 wherein the valve seat is disposed proximate the inlet port and the spring acts to bias the element and the closure away from the inlet port.
- 22. A valve as set forth in claim 17 wherein the operating mechanism comprises a spring, and the closure comprises a cylindrical body that is resiliently biased by the spring away from seating on the valve seat and that has a central region biased against a distal end of the post so as to allow the closure to tilt slightly relative to the post for compliant seating on the valve seat.
- 23. A valve as set forth in claim 16 wherein the armature tube is selectively positioned coaxially with respect to a central through-hole of the electric actuator, and the valve seat is disposed within the actuator through-hole.
- 24. A valve as set forth in claim 22 wherein the element and the closure are disposed within the actuator through-hole when the closure is seated on the seat.
- 25. A valve for selectively venting headspace of a fuel tank in an automotive vehicle having an engine that is powered by volatile fuel stored in the tank, the valve comprising:a body having an inlet port adapted to be communicated to the tank headspace, an outlet port, and a vent passage between the ports; a valve seat circumscribing the passage; a closure for selectively seating on, and unseating from, the seat to selectively close, and open, the passage; an operating mechanism comprising an electric actuator comprising an electromagnet coil that is disposed about a central through-hole and is selectively energized by electric current to selectively position an armature with respect to the central through-hole to cause the closure to seat on, and unseat from, the seat; wherein the seat and the closure are disposed within the central through-hole, and the armature comprises a through-passage having opposite ends, one of which is disposed within the through-hole and is toward the closure and the other of which is toward one of the ports, to provide for flow through the passage to pass through the through-passage in the armature when the closure is unseated from seat.
- 26. A vent valve as set forth in claim 25 including an element that is fit to the armature at the one end thereof and comprises at least one through-opening through which flow enters the through-passage after having passed the unseated closure.
- 27. A vent valve as set forth in claim 25 wherein the seat is disposed at a distal end of a riser that is disposed on a wall of the valve body in circumscribing relation to the vent passage.
- 28. A vent valve as set forth in claim 27 wherein the seat comprises a surface of the riser.
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Number |
Name |
Date |
Kind |
4986246 |
Kessler de Vivie et al. |
Jan 1991 |
A |
5809977 |
Krimmer |
Sep 1998 |
A |
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Nov 2000 |
A |