Abstrict A flow meter is provided having a housing with inlet and outlet
ports respectively adapted to be connected with a source of fluid
pressure and a fluid user. A semicircular vane member mounted within
the housing is movable in response to a change in the flow rate
between the inlet and outlet ports to rotate a shaft to which the
vane member is attached. The shaft, in turn, extends externally
of the housing and is operatively coupled to an indicator for providing
an external visual indication of the rate of fluid flow through
the flow meter. The improvement, however, comprises a unitary spring
seal having a first portion rigidly secured to the housing and a
second portion which extends between the housing and the vane shaft.
This second portion extends along the shaft within the housing and
is resiliently urged against the outer peripheral surface of the
shaft in order to prevent fluid leakage between the vane shaft and
the housing.
Claims I claim:
1. A flow indicator device for a fluid system comprising a housing
having a chamber, an inlet port and an outlet port registering with
said chamber and adapted to be connected with said system; an interior
wall extending into said chamber intermediate said inlet port and
said outlet port; a vane member rotatably mounted in said housing
on an axis disposed closely adjacent the free edge of said interior
wall whereby said wall and said vane member cooperate to separate
said inlet port from said outlet port; said housing being provided
with interior walls having a substantially semi-spherical inner
surface, said vane member having a substantially semicircular edge
rotatable adjacent said semi-spherical surface, the center of said
semi-spherical surface being displaced from the center of the semi-sphere
circumscribed by said circular edge upon rotation of said vane member,
whereby the space between said edge and said surface varies at each
rotative position of said vane member; a shaft having opposite ends
rotatably mounted in said housing; means mounting said vane member
to said shaft such that said vane member rotates with said shaft
about the axis of rotation of said shaft; the improvement comprising
a one piece seal member, said seal member being thin walled and
constructed of a resilient material, said seal member having a first
portion and means for rigidly securing said first portion to said
housing so that part of said first portion flatly abuts against
said housing, and a second portion of said seal member formed at
an end of said first portion and extending between said housing
interior wall and said mounting means, said second portion extending
substantially entirely along and abutting against the outer peripheral
surface of said mounting means to prevent fluid leakage between
said vane mounting means and said housing interior wall
and
wherein said seal member is formed so that said second portion
of said seal member is resiliently urged against said mounting means
when said first portion of said seal member is secured to said housing.
2. The invention as defined in claim 1 wherein said seal member
is made of spring metal.
3. The invention as defined in claim 1 wherein said first portion
of said seal member is planar and includes an opening in registry
with the inlet port and through which the influent to said device
passes.
4. The invention as defined in claim 3 wherein a part of the first
portion of said seal member between said opening and said vane shaft
flatly abuts against the housing and extends substantially entirely
along the length of said vane shaft within said chamber.
5. The invention as defined in claim 3 wherein the first portion
of the seal member is secured to said housing by threaded fasteners.
6. The invention as defined in claim 1 and in which said mounting
means comprises a sleeve secured to said shaft, said sleeve having
a cylindrical outer periphery around at least a portion thereof,
and wherein a part of said second portion of said seal member conforms
in shape to said cylindrical portion of said sleeve.
Description BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates generally to fluid flow meters and,
more particularly, to a fluid meter with new and improved means
for providing a seal between the vane member and an internal wall
which separates the inlet and outlet ports for the flow meter.
II. Description of the Prior Art
A variety of measuring devices and the like are now available for
supplying information regarding the rate of flow in a fluid flow
system. One such type of instrument, commonly called a flow meter,
comprises a rate flow indicator in which a semicircular vane member
is rotatably mounted and movable by fluid flow through the device.
The vane member is connected with indicating means to indicate exteriorly
of the device the rotational position of the vane member and thus
the rate of flow through the device.
As the semicircular vane member is rotated by fluid flowing through
the device, it moves along a hemispherical wall section having its
pivotal axis offset from the center of the wall section so that
pivotal movement of the vane creates an opening between the outer
edge of the vane and the wall section. This opening increases in
cross-sectional area as the vane moves from a closed and to a maximum
open position. In this way, the flow meter does not unduly interfere
with the rate of fluid flow through the device.
One problem associated with such flow meters is that the leakage
past the edge of a vane member in the area where the vane member
is pivotally mounted will seriously impair the accuracy of the device
and this is particularly true for high fluid pressure applications.
Previous attempts to cure this problem by providing a seal between
the vane shaft and the housing oftentimes results in a large amount
of friction between the seal and the vane shaft. Such friction in
turn inhibits the movement of the vane member and thus adversely
effects the accuracy of the flow meter.
One previously known device designed to overcome this problem is
disclosed in U.S. Pat. No. 3776037 entitled "FLOW INDICATOR
DEVICE WITH SEALING MEANS" which issued on Dec. 4 1973. In
this prior patent, a teflon shoe is mounted in a slot formed within
the housing so that one edge of the teflon shoe abuts against the
vane shaft. Compression springs are also positioned between the
housing and the other edges of the teflon shoe and urge the teflon
shoe against the vane shaft. While this prior known device has proven
effective in use, it is relatively expensive to construct the housing
with the necessary receiving slot for the teflon shoe and its associated
springs.
SUMMARY OF THE PRESENT INVENTION
The present invention provides a solution to this problem by providing
an inexpensive and yet effective means for sealing the vane member
about its vane shaft to prevent leakage from the inlet to the outlet
port of the flow meter.
In brief, the flow meter of the present invention comprises a housing
having an inlet port and an outlet port and a flow responsive vane
member carried within the housing between the inlet and outlet ports.
The vane member is secured to a shaft which is rotatably mounted
to the housing and the shaft in turn is operatively connected with
an indicator means externally of the housing. A housing wall separates
the inlet port from the outlet port and the vane member is rotatably
mounted within the housing chamber adjacent the free edge of the
housing wall. As with the previously known flow meters, the outer
circular edge of the vane cooperates with a hemispherical wall section
having its center offset from the axis of rotation of the vane.
Thus, rotation of the vane creates an opening having a variable
cross-sectional area between the outer circular edge of the vane
member and the hemispherical wall portion.
The novelty of the instant invention, however, lies in the provision
of an improved means for sealing the vane to the free edge of the
housing wall in order to prevent fluid leakage between the wall
and the vane member. The improved sealing means comprises a unitary
and substantially planar spring member which is constructed of a
resilient material, such as spring metal. One portion of the spring
member is rigidly secured to the flow meter housing while a second
portion of the spring member abuts against the vane member around
its pivotal mounting means for substantially the entire length of
the vane member. Moreover, the resilient spring member is formed
so that the second portion of the spring member resiliently abuts
and seals against the vane member.
In the preferred form of the invention, the second portion of the
spring member is shaped to conform to the outer periphery of the
vane member mounting means in order to minimize friction between
the seal member and the vane member. Thus, a sealing contact is
maintained between the spring member and the vane member mounting
means without unduly interfering with the rotation of the vane member.
BRIEF DESCRIPTION OF THE DRAWING
A better understanding of the present invention will be had upon
reference to the following detailed description when read in conjunction
with the accompanying drawing wherein like reference characters
refer to like parts throughout the several views, and in which:
FIG. 1 is a top view of a flow meter constructed in accordance
with the present invention and with parts broken away;
FIG. 2 is a sectional view taken substantially along line 2--2
in FIG. 1 and enlarged for clarity;
FIG. 3 is a fragmentary sectional view taken substantially along
line 3--3 in FIG. 2;
FIG. 4 is a sectional view taken substantially along line 4--4
in FIG. 2;
FIG. 5 is a side view of the indicator means taken substantially
along line 5--5 in FIG. 1; and
FIG. 6 is a perspective view illustrating one component of the
flow meter of the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
With reference first to FIGS. 1 2 and 4 the fluid flow meter
10 according to the present invention is thereshown and includes
a housing 12 having an upper wall 14 and a lower circular flange
16. A fluid inlet port 18 is internally threaded for connection
with a fluid system (not shown) via standard fluid connectors. Similarly
the housing 12 also includes an outlet port 20 which is internally
threaded for connection with a fluid system via conventional fluid
fittings.
Referring now to FIG. 2 an interior wall 22 extends downwardly
from the upper housing wall 14 and has a lower free edge 24 which
terminates short of the housing circular flange 16. The internal
wall 22 separates the inlet 18 from the outlet 20 and defines an
inlet chamber 26 and an outlet chamber 28. Each of the chambers
26 and 28 are open through the lower end of the housing 12 but are
on opposite sides of the internal wall 22.
With reference to FIGS. 2 and 4 the flow meter 10 further includes
a bowl 30 having an outwardly extending annular mounting flange
32 which registers with the lower end 16 of the housing 12. The
bowl 30 is secured to the housing 12 by bolts 34 and appropriate
sealing means 36 such as an O-ring, are disposed between the bowl
30 and housing 12 to fluidly seal them together.
The bowl 30 has an interior hemispherical surface 38 with a center
at point 40 and thus defines an interior flow chamber 42 which is
open through the upper end of the bowl 30. The bowl 30 also includes
a lower stem 44 wih an interiorly threaded throughbore 46 which
is open to the chamber 42. A plug 48 having a pin 50 secured to
it is threadably connected to the bore 46 so that the pin 50 extends
upward and into the flow chamber 42 for a reason to be subsequently
described. Suitable means are also provided for fluidly sealing
the plug 48 to the bowl 30.
Referring now particularly to FIG. 4 registering bores 52 and
54 are formed through the housing 12 so that the bores 52 and 54
are substantially parallel to the lower edge 24 of the housing wall
22. The bores 52 and 54 are spaced downwardly from the edge 24 of
the wall 22 but at a position above the center 40 of the hemispherical
wall surface 38. A shaft 56 is positioned through the bores 52 and
54 and, at one end, is rotatably mounted to the housing 12 by a
bearing assembly 58. This end of the housing 12 is then closed by
a closure cap 60 and a suitable seal 62 prevents fluid leakage along
the shaft 56. The other end of the shaft 56 extends externally of
the housing 12 and into the interior of an indicator housing (FIG.
1) 64 for a reason to be shortly described. The indicator housing
64 also is secured to the flow meter housing 12 by suitable means,
such as bolts (not shown).
Referring now to FIGS. 2 and 4 a vane member 68 is provided having
an outer semicircular edge 70 and an inner straight edge 72. A tubular
and cylindrical sleeve 74 is secured to or formed as a part of the
straight edge 72 of the vane member 68. The shaft 56 extends through
the sleeve 74 and the sleeve 74 is secured to the shaft 56 by any
suitable means, such as screws 76. Thus, the vane member 68 rotates
in unison with the shaft 56.
Preferably, the radius of the vane member 68 is substantially the
same as the radius of the hemispherical wall section 38. The axis
of rotation of the vane member 68 however, is spaced upwardly from
and thus offset from the center 40 of the hemispherical wall section
38. Thus, rotation of the vane member 68 creates a curved opening
between the outer edge 70 of the vane member 68 and the hemispherical
wall 38 which increases in cross-sectional area as the vane member
68 is rotated from its closed position illustrated in solid line
in FIG. 2 to its open position, illustrated in phantom line in
FIG. 2. the pin 50 moreover, limits the maximum open rotation of
the vane member 68.
With reference now to FIGS. 1 and 5 the indicator housing 64 is
open at one end 80 and this open end 80 is in turn closed by a cover
plate 82 having a transparent window 84. The indicator housing 64
and cover 82 thus defines an indicator housing chamber 86 into which
the shaft 56 at least partially extends. A cylindrical shaft extension
88 having a coaxial stem 90 is secured to the portion of the shaft
56 extending into the indicator housing 64 by any suitable means.
The shaft extension 88 further includes a spring mechanism (not
shown) which resiliently urges the shaft 56 with its attached vane
member 68 to a closed position, i.e. with the vane member 68 adjacent
the inlet chamber 26.
An indicator needle 94 is secured at one end to the free end of
the shaft extension stem 90 by a screw 96. The other end of the
indicator needle cooperates within indicia plate 98 secured to the
housing 64. The indicia plate 98 is visible through the window 84
on the cover plate 82 and the position of the indicator needle 94
with respect to the indicia plate 98 is indicative of the rotational
position of the vane member 68 and thus of the flow rate through
the flow meter.
Still referring to FIGS. 1 and 5 a cam member 100 having an outer
cam surface 102 is secured to the shaft extension stem 90 by any
suitable means. A cam follower 104 on an electrical switch 106 abuts
against the cam surface 102 so that the cam surface 102 activates
the switch 106 at a predetermined rotational position of the shaft
56. The switch 106 for example, can be secured to an alarm system
to activate the alarm system when the fluid flow through the flow
meter falls below a predetermined lower limit.
The novelty of the instant invention, however, resides in the means
for sealing the sleeve 74 on the vane member 68 to the interior
wall 22 in order to prevent fluid leakage between the vane member
and the interior wall 22.
With reference then to FIGS. 2 3 and 6 the improved sealing means
110 of the present invention is thereshown and comprises a substantially
planar seal member 112 which is made of a resilient material and
preferably spring metal. The seal member 112 is preferably of a
unitary construction.
The seal member 112 further includes a first portion 114 which
flatly abuts across the lower end 113 of the housing 12 beneath
the inlet chamber 26 and is rigidly secured to the housing 12 by
bolts 116. The seal member 112 however, includes an opening 118
formed through it which registers with the inlet chamber 26. The
opening 118 ensures that the fluid flow from the inlet chamber 26
and into the bowl chamber 42 is unimpeded by the seal member 112
and the fluid flow is in a direction generally perpendicular to
the plane of the seal member 112. Moreover, an intermediate part
115 of the first portion flatly abuts against the lower end 113
of the housing 12 between the inlet chamber 26 and the housing wall
22.
Still referring to FIGS. 2 3 and 6 the seal member 112 includes
a second portion 120 spaced downwardly (FIG. 2) from the first portion
114 and having an abutment surface 122 which abuts against the vane
mounting sleeve 74 along substantially the entire length of the
sleeve 74 as best seen in FIG. 3 within the bowl chamber 42. Moreover,
the seal member 112 is formed so that the surface 122 is resiliently
urged against the sleeve 74 and, in the preferred form of the invention,
the surface 122 is arcuate and conforms with the outer peripheral
surface of the sleeve 74. By this arrangement, the second portion
120 of the seal member 112 resiliently and sealingly engages the
vane mounting sleeve 74 while at the same time minimizing the frictional
engagement between the seal member second portion 120 and the sleeve
74.
In operation, fluid flow into the housing inlet 18 rotationally
displaces the vane member 68 in an amount proportional to the fluid
flow rate and in the well known manner. This rotational displacement
of the vane member 68 is imparted to the shaft 56 which in turn
rotates the needle 94 to provide an indication on the indicia plate
98 of the fluid flow rate through the flow meter.
The means 110 for sealing the vane sleeves 74 to the internal wall
22 of the housing 12 effectively prevents the leakage of fluid between
the sleeve 74 and the internal wall 22. The seal member 112 is further
advantageous in that the flow of fluid from the fluid inlet chamber
26 and into the bowl chamber 42 is substantially perpendicular to
the plane of the seal member 112 so that the noral flow of fluid
is directed around the outer circular periphery 70 of the vane member
68 in the desired fashion. Moreover, the seal member 112 is further
advantageous in that it can be inexpensively constructed and easily
and rapidly installed in the flow meter by simply screwing the first
portion 114 of the seal member 112 to the housing 12.
The flow meter 10 according to the present invention is particularly
advantageous for high pressure applications where any inaccuracy
of the vane member 68 caused by friction between the seal member
112 and the vane sleeve 74 is negligible. In any event, the sleeve
74 is typically constructed of metal and the metal to metal contact
between the sealing surface 122 and the vane sleeve 74 is minimized.
The bearing assembly 58 between the housing 112 and the vane shaft
56 also enhances the free rotation of the vane shaft 56.
As is best seen in FIG. 2 the second portion 120 of the seal member
112 is spaced downwardly from the housing, and during operation
of the flowmeter, debris in the fluid will accumulate between the
second portion 120 of the seal member 112 and the vane sleeve 74.
However, since the seal member 112 is constructed of a resilient
material, upon the application of a shock force to the seal member
112 the seal member 112 deflects upwardly toward the housing thus
forming a space between the seal member 112 and vane sleeve 74 for
a very short period of time. During this short period of time, however,
a portion of the influent flows from the inlet chamber 26 between
the seal member 112 and vane sleeve 74 and to the outlet chamber
28 thus removing any accumulated debris between the seal member
112 and the vane sleeve 74.
Having described my invention, however, many modifications thereto
will become apparent to those skilled in the art to which it pertains
without deviation from the spirit of the invention as defined by
the scope of the appended claims. |