Abstrict A protective shield for the sight glass of a flow meter. The flow
meter includes an elongated guard having a slot that houses a sight
glass, and a flow indicator carried by a float moves vertically
within the sight glass and the fluid flow is read on a scale mounted
on the guard and bordering the slot. A transparent open-ended protective
sleeve is disposed around the guard and is retained on the guard
by a spring clip that extends inwardly of the sleeve and engages
an abutment on the outer surface of the guard.
Claims I claim:
1. A flow meter, comprising a body having a fluid inlet and fluid
outlet and having a passage connecting said inlet and outlet, a
float assembly disposed within said passage and adapted to move
within the passage in accordance with the rate of flow of fluid
therethrough, a guard connected to the body and having an elongated
recess, a transparent sight glass disposed within the recess, a
rod connected to the float assembly and extending within the sight
glass, an indicator connected to the rod, a scale mounted adjacent
said recess, movement of the indicator within the sight glass indicating
the rate of flow on the scale, a tubular shield disposed around
the guard and having a transparent portion disposed in alignment
with said sight glass and said scale, an abutment on said guard,
and spring clip means mounted on the shield and engaged with the
abutment to prevent longitudinal movement of the shield with respect
to said guard, an outer surface of the guard being generally flat
and said abutment being spaced circumferentially from said surface,
said shield being installed on said guard with said spring clip
means being disposed generally parallel to said surface, rotation
of said shield causing said spring clip means to deform outwardly
and to seat against said abutment.
2. The flow meter of claim 1 wherein said spring clip means extends
chord-wise across the interior of said shield.
3. The flow meter of claim 1 wherein said shield is provided with
a pair of circumferentially spaced openings, and the ends of said
spring clip means are secured within said openings.
4. A flow meter, comprising a body having a fluid inlet and a fluid
outlet and having a passage connecting said inlet and outlet, a
float assembly disposed within said passage and adapted to move
within the passage in accordance with the rate of flow of fluid
therethrough, a guard connected to the body and having an elongated
recess, a transparent sight glass disposed within the recess, a
rod connected to the float assembly and extending within the sight
glass, an indicator connected to the rod, a scale disposed adjacent
said recess, movement of the indicator within the sight glass indicating
the rate of flow on the scale, a transparent impact resistant plastic
sleeve disposed around the guard, a flexible connecting member disposed
within said sleeve, said connecting member having a locking position
and being capable of being deformed outwardly from said locking
position, and abutment means on the outer surface of said guard
and disposed to be engaged by said connecting member when said connecting
member is in said locking position said connecting member having
a pair of opposite ends, said ends being connected to said sleeve
at circumferentially spaced locations and said connecting member
extending chord-wise between said locations, said guard having a
generally flat surface spaced circumferentially from said abutment
means, said sleeve being initially inserted around the guard with
said connecting member disposed generally parallel to said flat
surface, said sleeve being rotated causing said connecting member
to deflect outwardly and said connecting member being biased to
its locking position as the connecting member is rotated to the
region of said abutment means to thereby effect engagement of said
abutment means by said connecting member.
5. A flow meter, comprising a body having a fluid inlet and a fluid
outlet and having a passage connecting said inlet and outlet, a
float assembly disposed within said passage and adapted to move
within the passage in accordance with the rate of flow of fluid
therethrough, a guard connected to the body and having an elongated
recess, a transparent sight glass disposed within the recess, a
rod connected to the float assembly and extending within the sight
glass, an indicator connected to the rod, a scale mounted adjacent
said recess, movement of the indicator within the sight glass indicating
the rate of flow on the scale, a tubular shield disposed around
the guard and having a transparent portion disposed in alignment
with said sight glass and said scale, spring clip means including
a central section extending generally chord-wise across the interior
of said shield, said guard having a longitudinally extending recess
disposed to receive said central section of said clip means as said
shield is inserted around said guard, and a laterally extending
abutment on said guard and spaced circumferentially from said recess,
rotation of said shield relative to said guard causing said central
section to deform outwardly and to seat against said abutment to
prevent outward longitudinal displacement of said shield relative
to said guard.
6. The flow meter of claim 5 wherein in the ends of said clip
means are disposed within openings in said shield.
7. The flow meter of claim 5 wherein said recess comprises a generally
flat longitudially extending surface on said guard, said central
section of said clip means being disposed generally parallel to
said surface as said shield is inserted on said guard.
Description BACKGROUND OF THE INVENTION
Float-type flow meters are frequently used to measure the flow
of air, industrial gases or other fluids. In flow meters of this
type, a float is mounted for movement within a tapered passage in
the body of the meter and the float will rise in proportion to the
rate of gas flow. The float carries a rod which extends downwardly
into an elongated guard that houses a sight glass. An indicator
mounted on the lower end of the rod moves within sight glass in
accordance with movement of the float and indicates the rate of
gas flow on a calibrated scale that is mounted on the guard adjacent
the sight glass.
If the flow meter is subjected to extreme high or sudden surge
pressure conditions, as could occur in the event of a malfunction
of the pressure regulator or by the normal sudden opening of a solenoid
valve in the fluid line, the high or sudden pressure could fracture
the sight glass. Therefore, it is desirable to provide a protective
shield around the sight glass to prevent glass fragments from dispersing
into the surrounding atmosphere in the event of fracture.
In addition, the scale and sight glass on an industrial-type flow
meter may become contaminated with dirt, oil and other foreign material
making it difficult to read the rate of flow, and in certain instances
it is difficult to adequately remove the contamination from the
sight glass and scale.
SUMMARY OF THE INVENTION
The invention is directed to a protective shield for a sight glass
of a float-type flow meter. The flow meter includes an enlongated
guard which extends downwardly from the body of the flow meter and
has a slot or recess that houses a sight glass. An indicator carried
by the float rod moves within the sight glass and the flow is read
on a scale which is mounted on the guard bordering the slot.
Disposed around the guard is a transparent open-ended shield or
sleeve, and the shield is retained on the guard by a spring clip
that extends chord-wise across the interior of the sleeve. The spring
clip is adapted to engage an abutment on the outer surface of the
guard to prevent longitudinal displacement of the shield from the
guard.
To install the shield, the shield is inserted onto the guard with
the spring clip disposed gernerally parallel to the flat scale.
The shield is then rotated, causing the spring clip to be deformed
outwardly until the spring clip reaches the region of the abutment
on the guard, and the spring clip will then snap inwardly into engagement
with the abutment to lock the shield in position on the guard.
The sleeve or shield, being formed of impact resistant plastic,
will protect the sight glass from external impact and will prevent
glass fragments from being dispersed into the atmosphere in the
event the sight glass should fracture due to internal pressure.
In addition, the shield will prevent the sight glass and graduated
scale from becoming contaminated by oil, grease, dirt or other foreign
material, and if the shield itself becomes contaminated it can be
readily wiped clean to restore its original condition. The shield
can be readily installed with either new flow meters or it can be
retrofitted to existing flow meters in the field. No auxiliary parts
or fasteners are required to install the shield, and it can be quickly
installed by merely inserting around the guard and rotating it until
the spring clip engages the abutment.
Other objects and advantages will appear in the course of the following
description.
DESCRIPTION OF THE DRAWINGS
The drawings illustrate the best mode presently contemplated of
carrying out the invention.
In the drawings:
FIG. 1 is a longitudinal section of a conventional flow meter incorporating
the protective shield of the invention; FIG. 2 is a transverse section
of FIG. 1.
FIG. 3 is a view similar to FIG. 2 showing the shield as it is
initially installed on the guard; and
FIG. 4 is a section taken along line 4--4 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a typical float-type flow meter incorporating
the protective shield of the invention. The flow meter includes
a body 1 having an inlet 2 into which a fluid, such as air, industrial
gas or oil, is introduced and an outlet 3 for the discharge of fluid.
A tapered passage 4 connects the inlet and outlet, as shown in FIG.
1.
Float assembly 5 is mounted for vertical movement within tapered
passage 4 and the float assembly will rise and fall within the
tapered passage in proportion to the rate of flow of gas in a conventional
manner.
A stem or rod 6 is connected to float assembly 5 and extends downwardly
through the lower open end of the body into an elongated guard 7
which is connected to the lower end of the body through threaded
nut 8.
A tubular sight glass 9 is mounted within guard 7 and an indicator
10 carried by the lower end of stem 6 moves within the sight glass
in accordance with movement of the float assembly within the tapered
passage 4. Guard 7 as shown in FIGS. 1 and 2 includes an upper
flanged end 11 which is clamped against the body by nut 8 and a
pair of elongated slots 12 and 13 are formed in opposite sides of
the guard and extend substantially the full length of the guard.
As shown in FIG. 2 the surfaces of guard 7 bordering the slot 12
are flattened and a conventional graduated scale 15 is mounted on
flattened surfaces 14. Scale 15 is provided with a central opening
aligned with slot 12 so that sight glass 9 and indicator 10 is visible
through slot 12.
In accordance with the invention, a transparent plastic sleeve
shield 16 formed of an impact resistant plastic material, such as
polycarbonate or the like, is disposed around guard 7. To connect
shield 16 to guard 7 a spring clip 17 is secured within a pair
of circumferentially spaced openings 18 in the lower portion of
the shield. As best shown in FIG. 2 spring clip 17 extends chord-wise
across the interior of shield 16 and is engaged with a ledge or
abutment 19 at the lower end of slot 13 on guard 7. Engagement of
the spring clip 17 with the abutment 19 prevents shield 16 from
being withdrawn from guard 7.
To install shield 16 the shield is inserted around guard 7 in
the manner shown in FIG. 3 in which the spring clip 17 is parallel
to scale 15. With the upper end of shield 16 in engagement with
nut 8 the shield is then rotated 180.degree. causing spring clip
17 to be deformed outwardly as it is rotated. Due to its resilient
nature spring clip 17 will snap back to its original position in
the region of the slot 13 above abutment 19 to preventing the shield
from being withdrawn from the guard.
The protective shield of the invention is an inexpensive and simple
device which can be readily installed and removed from the guard.
As the spring clip 17 is permanently fixed to the shield there are
no auxiliary parts or fasteners that are required to be used when
installing the shield.
As the shield is transparent, indicator 10 and scale 15 are visible
through the shield, and the shield will not only protect the surrounding
area from glass fragments in the event the sight glass should fracture
due to excessive internal pressure, but also protects the sight
glass and scale from external impact and contamination.
Various modes of carrying out the invention are contemplated as
being within the scope of the following claims particularly pointing
out and distinctly claiming the subject matter which is regarded
as the invention. |