Valve

A valve including indicating means for indicating overtravel of an operating member beyond its normally closed position for warning that replacement of a seal is necessary. A diaphragm valve has a diaphragm of a material which withstands repeated flexing and is clamped in a unique manner.

BACKGROUND OF THE INVENTION 
This application relates to the art of valves and, more particularly, to 
valves having means for indicating various operating conditions thereof, 
and to diaphragm valves of the type having a diaphragm clamped between 
body and bonnet members. Although the invention will be described with 
particular reference to diaphragm valves and rotatably operable valve 
members, it will be appreciated that the invention has broader 
applications, and that certain individual features thereof may be used 
with other types of valves and/or in other environments. 
Diaphragm valves of known types include a circular diaphragm clamped in a 
circumferential area between body and bonnet members. The diaphragm fails 
after a certain number of cycles and may also fail due to the manner in 
which it is clamped. It has been considered desirable to develop a 
diaphragm valve which included a diaphragm of increased strength capable 
of withstanding a greater number of cycles before failure. Such a valve 
would include means for clamping the diaphragm in a manner insuring good 
diaphragm sealing while minimizing stress failures. 
Valves commonly include indicating means for indicating various flow 
positions of the valve member. In many applications where metal seal 
packless valves are used, indication of flow position is critical from a 
safety standpoint. In previous arrangements, indication of flow position 
was designated by a simple marking or required the operator to recognize 
handle orientation relative to the valve body. In the latter case, some 
types of mountings prohibit this type of recognition. 
In previous arrangements, the rotatable operating member is restricted from 
being moved beyond the set, off position of the valve. If overtravel 
beyond the off position without adjustment of the valve is not possible, 
two problems will result after seal wear has occurred. First, the valve 
cannot be shut off, and second, the handle could be broken by an operator 
attempting to forcedly close the valve. 
When there is no stop means for stopping the operating member in its off 
position, the operating member may inherently overtravel beyond the off 
position due to seal wear. Only a highly skilled person would be aware 
that at some point such overtravel would signify that replacement of the 
seal was necessary, and there was no associated means for indicating the 
point at which such seal replacement was necessary. Therefore, it would be 
desirable to have an alarming indicating means for clearly indicating to 
an operator that a seal is worn beyond its normal, useful life and that 
replacement is necessary. 
The subject invention meets the foregoing needs and others, and provides a 
new and improved valve construction. 
SUMMARY OF THE INVENTION 
A diaphragm valve of the type described includes a circular diaphragm of 
austenitic stainless steel having a hardness not less than 38 on the 
Rockwell C scale. The austenitic stainless steel is preferably of AISI 
type 316. 
In accordance with the present application, the diaphragm is axially 
clamped in a circumferential area inwardly of its outer periphery between 
opposed flat and parallel clamping surfaces. It has been found that 
diaphragm discs normally have a burr on the outer peripheral edge thereof 
due to stamping of same from a sheet. When attempts are made to clamp the 
outer periphery of the diaphragm between opposed surfaces, the burr 
prevents high pressure squeezing on mating flat surfaces of the diaphragm. 
In a preferred arrangement, the diaphragm is clamped in axially and 
radially spaced circumferential areas connected with one another by an 
axially bent diaphragm portion. The maximum squeeze or clamping force is 
applied to the diaphragm at the inner circumferential area and the 
diaphragm is bent across relatively sharp corners. 
The diaphragm is clamped between body and bonnet members, one of which 
includes an axially extending outer circumferential flange for protecting 
the clamping surface of the member on which it is provided. The other 
member includes a circumferential recess opposite from the circumferential 
flange for accommodating the outer periphery of the diaphragm in free and 
unclamped relationship. 
The diaphragm valve includes a valve member on one side of the diaphragm 
having a non-circular head slidably guided in a cylindrical bore. The 
non-circular arrangement of the enlarged head is such that fluid flow can 
occur therepast for purging. The valve member includes a cylindrical stem 
axially guided in the bore through a guide washer having a non-circular 
inner surface to accommodate fluid flow therepast for purging purposes. 
The diaphragm valve constructed in accordance with the present application 
can be actuated in a plurality of manners, including manual and remote 
actuating means. The arrangement specifically shown in the present 
application includes a manually operated rotatable operating member. 
However, it will be appreciated that the manually rotatable operating 
member of the present application is not required for operating the 
diaphragm valve, and that it can be used with valves of other types. 
The invention also relates to a valve which includes a bonnet having a 
rotatable operating member for moving a valve member between open and 
closed positions. The valve member carries a wearable seal cooperable with 
a valve seat in the valve member closed position. The valve member is 
rotatable between open and closed positions, and the closed position 
includes angular ranges over which the seal is effective. One range 
includes a normal angular range over which the seal is in satisfactory 
condition, and a second range includes an overtravel or abnormal angular 
range over which the seal is still functional but should be replaced. 
In accordance with the present application, indicating means is provided 
between the valve operating member and the valve bonnet for indicating 
overtravel of the operating member beyond the normal closed position 
thereof to indicate that replacement of the seal is necessary. 
In a preferred arrangement, the indicating means of the present application 
includes means for indicating a range of normal angular closed positions 
and a range of abnormal closed angular positions for the operating member. 
When the operating member overtravels beyond the normal closed position, 
the operator will be readily aware that replacement of the seal is 
necessary. 
In a preferred arrangement, the indicia for indicating overtravel of the 
operating member takes the form of adjacent arcuate bands of different 
color on the bonnet for cooperation with an indicator on the operating 
member. When the seal is satisfactory, the indicator on the operating 
member is aligned with the color band indicating normal valve closure. 
When the seal is worn and requires replacement, the indicator on the 
operating member is aligned with the color band indicating overtravel or 
that replacement of the seal is required. 
In one arrangement, the indicating means includes an indicating ring member 
mounted on the valve bonnet beneath the operating member. Specifically, 
the indicating ring member is mounted on an outer cylindrical end portion 
of the valve bonnet, and is held thereto by frictional engagement. The 
indicating ring member includes a central opening or hole receiving an 
outer cylindrical end portion of the valve bonnet, and has axially 
extending flange means surrounding the opening for frictionally gripping 
the outer end portion of the valve bonnet. 
Locating means is provided between the locating ring member and the valve 
bonnet for locating the ring member in a desired rotated position for 
locating the indicia thereon at the desired angular location. The locating 
means may take many forms and, in one arrangement, includes a longitudinal 
groove in the outer end portion of the bonnet receiving an inwardly 
extending tab on the indicating ring member. The tab on the indicating 
ring member is located a predetermined distance from the indicia thereon, 
and the groove in the bonnet is located a predetermined distance from a 
stop surface which normally cooperates with a stop projection on the 
operating member to stop same in the valve open position. 
The indicating ring member includes an inclined surface having the indicia 
thereon and being visible in directions both parallel and perpendicular to 
the longitudinal axis of the operating member. The indicating ring member 
also includes an outer flange for concealing a panel mounting nut threaded 
on the bonnet. 
The principal object of the present invention is the provision of an 
improved diaphragm valve which is very economical to manufacture and 
assemble, and very reliable in operation. 
Another advantage of the invention is the provision of an improved 
diaphragm valve having an improved diaphragm material. 
A further advantage is the provision of an improved diaphragm valve having 
an improved arrangement for circumferentially clamping the diaphragm. 
Another advantage resides in the provision of an improved diaphragm valve 
having an axially movable valve member with cooperating hexagonal and 
circular guide surfaces for allowing purging. 
Still another advantage of the invention is found in the provision of a 
valve having a rotatable operating member and including indicating means 
for indicating operating member overtravel which requires replacement of a 
valve seal. 
A further advantage of the invention is the provision of indicating means 
for indicating various positions of a rotatable operating member. 
Yet a further advantage is the provision of an improved ring member secured 
to a valve bonnet in a unique manner for performing diverse functions such 
as concealing a panel mounting nut or providing indicating positions for 
the valve operating member. 
Other advantages and benefits of the invention will become apparent to 
those skilled in the art upon a reading and understanding of the following 
detailed description.

DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring now to the drawings, wherein the showings are for purposes of 
illustrating certain preferred embodiments of the invention only and not 
for purposes of limiting same, FIG. 1 shows a valve body A and a valve 
bonnet B axially clamped together by a bonnet nut C in a known manner, and 
having a circular metal diaphragm D circumferentially clamped 
therebetween. Valve body A and bonnet nut C have cooperating threads 
therebetween generally indicated at numeral 12 for providing axial 
movement of bonnet nut C relative to body A upon rotational movement of 
bonnet nut C. Bonnet member B and bonnet nut C have cooperating generally 
radial shoulders 14 which abut one another for moving bonnet member B 
toward a body member A upon rotation of bonnet nut C in the appropriate 
direction to securely clamp diaphragm D therebetween. 
An axially movable valve member E has an enlarged head portion 18 slidably 
guided in a large diameter portion of a cylindrical bore 20. The outer end 
portion of enlarged head 18 facing toward diaphragm D is generally 
spherical and the outer periphery of enlarged head portion 18 is generally 
hexagonal so that only the corners thereof are guided in the cylindrical 
bore 20, while the flats thereof provide fluid passages to accommodate 
valve purging. A cylindrical stem portion 24 of valve member E is slidably 
guided through a guide washer 26 having a cylindrical outer surface 
closely received in a cylindrical small diameter bore portion 28, and 
having a hexagonal inner surface to provide passages to accommodate 
purging. 
Inlet and outlet ports 32,34 in valve body A communicate with the valve 
body bore on opposite sides of a circumferential upstanding seat 36. Fluid 
inlet and outlet lines (not shown) may be connected to inlet and outlet 
32,34, respectively, by convenient known means. A plastic, elastomeric or 
metal circumferential seal ring 38 is secured to an end portion of valve 
member E for selectve cooperation with seat 36 to prevent or allow fluid 
flow through the valve. In the "standard" version of the subject new 
valve, seal ring 38 is constructed from polytetrafluoroethylene. 
Seal 38 is attached to valve member E in the manner disclosed in U.S. Pat. 
No. 3,623,699 issued Nov. 30, 1971, to Matousek, et al., the disclosure of 
which is hereby incorporated herein by reference. Briefly, the end portion 
of valve member E includes a circumferential recess receiving seal ring 
38, and inner and outer rims on valve member E are deformed toward one 
another over the outer end face of the seal ring for holding same in 
position. This seal arrangement limits cold flow of the seal material 
which produces better control of the stroke of the valve. This 
consequently yields better control of diaphragm life which is related to 
stroke. 
A coil spring 40 under compression between guide washer 26 and enlarged 
head 18 normally urges the valve member E, i.e., seal ring 38, away from 
seat 36 to provide fluid communication between inlet 32 and outlet 34. In 
the open position of valve member E, fluid enters the entire cylindrical 
bore defined by large and small diameter portions 20,28. Upon closing of 
valve member E by movement of seal 38 back into engagement with seat 36, 
purging of fluid pressure within the bore is possible because of the 
hexagonal shape of enlarged head 18 and of the interior surface of guide 
washer 26. 
Bonnet B includes a stem G rotatably guided therein. Cooperating external 
and internal threads between stem member G and bonnet member B are 
generally indicated by numeral 44 to impart axial movement to stem member 
G upon rotational movement thereof relative to the bonnet. Instead of 
using threads, it will be recognized that many different axial operators 
can be provided for imparting axial movement to valve member E to effect 
movement between its open and closed positions, and that the manually 
operated rotatable operating member shown is only illustrative. An 
enlarged head 48 on valve stem G has a flat surface engaging a 
corresponding flat surface on a button 50 which, in turn, has a convex 
surface engaging diaphragm D on the opposite side thereof from enlarged 
head 18 of valve member E. The stem head and button are cooperatively 
mounted so as to facilitate relative rotation therebetween around the 
longitudinal axis of the stem. Button 50 may be of plastic or other 
suitable materials, and the interface between stem head 48 and the button 
is lubricated to assist allowing relative rotation between the stem and 
button instead of having the button rotate relative to diaphragm D. 
A rotatable operating member generally indicated at H is provided for 
moving valve member E between its open and closed positions. Enlarged head 
60 is splined onto stem G as at 62 for preventing relative rotation 
between the head and stem. An operating handle 62 is suitably connected to 
head 60, and may even be integral therewith. A nut 64 and lock washer 66 
secure head 60 to stem G, and a cover plate 68 snaps into a circular 
recess in the top of head 60 in a known manner. It will be recognized that 
valve operating member H includes head 60, handle 62, and stem G, and that 
operating member H is rotatable for moving valve member E axially between 
its open and closed positions. However, it will be appreciated that other 
operators may be provided if so desired for cooperating with diaphragm D 
to move the valve member between its open and closed positions. 
FIG. 2 shows an enlarged peripheral edge portion of body A and bonnet B 
having diaphragm D axially clamped therebetween. As shown in FIG. 1, 
bonnet member B has a generally conical surface portion 70 extending away 
from diaphragm D opposite from large diameter cylindrical bore portion 20 
in the valve body. Conical portion 70 and cylindrical bore portion 20 are 
also generally shown in FIG. 2 for reference purposes. Body member A and 
bonnet member B have spaced-apart opposite flat and parallel 
circumferential areas 76,78 between which an inner or primary 
circumferential area of diaphragm D is axially clamped over an inner 
circumferential area. Tightening of bonnet nut C in FIG. 1 moves clamping 
surfaces 76,78 toward one another for squeezing diaphragm D therebetween. 
As will be noted in FIG. 2, the circumferential area clamped between 
clamping surfaces 76,78 is spaced well inwardly from the diaphragm outer 
periphery. 
Body member A and bonnet member B also include secondary flat and parallel 
clamping surfaces 80,82 spaced axially and radially from primary clamping 
surfaces 76,78. Primary surfaces 76,78 are separated from secondary 
surfaces 80,82 by relatvely sharp corners 84,86 across which diaphragm D 
is bent axially as clearly shown in FIG. 2. The axial spacing between 
corners 84,86 is less than the normal axial thickness of diaphragm D and 
less than the axial spacing between clamping surfaces 76,78. As a result, 
corners 84,86 provide excellent seals against the opposite face surfaces 
of the diaphragm. Flat and parallel circumferential surfaces 80,82 are 
spaced-apart from one another no less than, and preferably slightly 
greater than, the spacing between primary clamping surfaces 76,78. The 
machining tolerances for body member A and bonnet member B are chosen such 
that the spacing between surfaces 76,78 will always provide maximum 
squeeze or clamping action as compared to the amount of squeeze or 
clamping action between surfaces 80,82. Such action insures that primary 
diaphragm sealing occurs at areas 76,78 to better accommodate valve 
purging. 
Continuing with reference to FIG. 2, an outer circumferential flange 90 
extends axially from secondary clamping surface 80 on body member A for 
protecting inner or primary clamping surface 76 against knicks and other 
damage during processing and assembly of the valve. The axial projection 
of flange 90 is substantially greater than the axial spacing between 
primary and secondary surfaces 76,80. Directly opposite from protective 
flange 90, bonnet member B is provided with an enlarged recess 94 for 
receiving a terminal end portion 96 of diaphragm D in a free and unclamped 
condition. Secondary corners generally indicated as 102,104 are axially 
spaced from one another a distance substantially less than the axial 
spacing between corners 84,86 so that the outer end portion 96 of 
diaphragm D is axially deformed to a greater degree than the axial 
deformation thereof between corners 84,86. 
As a result of the foregoing relationships, opposed pairs of flat clamping 
surfaces 76,78 and 80,82 define axially and radially spaced clamping 
surfaces for axially clamping diaphragm D at radially-spaced 
circumferential areas. Between the inner and outer circumferential 
clamping areas, diaphragm D is axially bent between corners 84,86. 
Diaphragm D is shown as comprising three discs or layers D1, D2, and D3 of 
equal thickness, although a greater or lesser number of such discs could 
be suitably employed in some instances. It has been found that such an 
arrangement provides enhanced flexibility without substantially reducing 
the strength or life of the composite diaphragm construction. In the 
preferred arrangement, each disc diaphragm forming disc comprises a flat 
circular member of austenitic type 316 stainless steel heat treated to a 
hardness of not less than 38 on the Rockwell C scale. Such hardness is 
considered to be a "fully hardened" condition for the particular material 
involved, and effectively enhances the overall cycle life of diaphragm D. 
Normally, stainless steel diaphragms are constructed from material having 
a hardness of approximately 27 on the Rockwell C scale, i.e., "quarter 
hard". It has been found that an increase in diaphragm hardness increases 
its strength which, in turn, increases its cycle life in a generally 
linear relationship. Thus, an increase in hardness from approximately 27 
to approximately 38 on the Rockwell C scale increases the diaphragm cycle 
life by a factor of about two. This result indeed comprises a significant 
improvement over prior art stainless steel diaphragm constructions. While 
316 stainless steel is employed in the preferred construction, it will be 
appreciated that other materials and hardness relationships could be used 
for different types of service. 
Typically, discs D1, D2, and D3 are stamped from sheet form and thus 
include a burr around the outer periphery thereof. The improved 
arrangement of the present invention, however, securely clamps the 
diaphragm at circumferential areas spaced radially inward from the outer 
periphery, so any burrs cannot possibly interfere with obtaining secure 
clamping and sealing. Discs D1, D2, and D3 are physically separate and are 
not bonded together in any way. The discs are held together simply by the 
clamping force exerted between the valve body and bonnet as described 
above. The laminated or layered diaphragm construction requires less force 
to flex, but has a strength which is about as great as a single layer 
diaphragm having the same thickness as the combined thickness of discs D1, 
D2, and D3. 
FIG. 3 shows enlarged hexagonal head 18 on valve member E as having its 
corners axially guided in large diameter bore portion 20. The flat areas 
of the head are spaced from the wall of the bore to accommodate valve 
purging. FIG. 4 shows cylindrical stem portion 24 of valve member E as 
being axially guided by flats defined by the internal hexagonal opening in 
guide washer 26. Spaces are advantageously defined between cylindrical 
stem 24 and the corners of the non-circular interior surface of washer 26 
to facilitate purging. 
Bonnet B is illustrated in FIG. 1 as including an external threaded portion 
108 receiving a panel nut 110. Threaded portion 108 is closely receivable 
through an opening in a panel (not shown), and the panel is clamped 
between the panel nut 110 and bonnet nut C to securely mount the valve 
thereto. Shims may be provided on the underside of the panel against 
bonnet nut C for desired location of panel nut 110 adjacent the outer end 
portion of bonnet B when the valve is in a mounted position. 
As shown with primary reference to FIG. 5 and with secondary reference to 
FIG. 1, the outer end portion of bonnet B includes a generally cylindrical 
surface 114 spaced radially inward from threaded portion 108 and separated 
therefrom by a circumferential radial shoulder 116. Cylindrical end 
portion 114 is cut-away as generally indicated at 120 over an axial extent 
less than the distance from its outer terminal end to shoulder 116. 
Cut-away portion 120 has opposite axially extending end surfaces 122,124, 
and the axial bottom of cut-away portion 120 is axially spaced slightly 
from radial shoulder 116 so that a substantially complete circumferential 
surface still exists around the outer end portion of the bonnet. End 
surfaces 122,124 may be angularly spaced from one another substantially 
greater than 90.degree. and less than 180.degree.. 
At least one end surface, i.e., end surface 124 defines a stop surface for 
stopping rotation of operating member H in its open position. A locating 
means in the form of an axial groove 130 is provided in the outer end 
portion of bonnet B. Groove 130 is angularly spaced approximately 
90.degree. from stop surface 124 as generally indicated by angle 134, and 
is used for purposes to be described. 
With continued reference to FIGS. 1 and 5, an indicating ring member J has 
a central opening or hole therethrough and is frictionally received on 
outer cylindrical end portion 114 of stem B. The central opening or hole 
includes generally axially extending flange means 138 for frictionally 
gripping bonnet outer cylindrical portion 114. It will be recognized that 
axially extending inner flange means 138 may be circumferentially 
continuous or may comprise a plurality of circumferentially-spaced flanges 
for frictionally or resiliently gripping the bonnet outer cylindrical 
portion. 
Inner flange 138 includes a terminal end 140 which normally abuts shoulder 
116 (FIG. 5). Ring member J includes a generally axially extending outer 
circumferential flange 142 having a terminal end 144 axially spaced a 
substantial distance away from the terminal end 140 of inner flange means 
138. Outer flange 142 surrounds, covers, and conceals panel nut 110 when 
the valve is mounted to a panel. A circumferential inclined surface 150 
extends from outer flange 142 toward the central opening in the ring 
member. In the arrangement shown, inclined surface 150 is inclined at an 
angle of approximately 45.degree. to longitudinal axis 152 of bonnet B, 
stem G and operating member H. A small circumferential horizontal portion 
156 extends between inclined surface 150 and the central opening in ring 
member J. Inclined surface 150 is located relative to head 60 and 
positioned such that it is visible in directions both parallel and 
perpendicular to longitudinal axis 152. 
As shown in FIG. 6, axially extending inner flange 138 on ring member J 
includes a radially inward extending tab 160 for close reception in groove 
130 of bonnet member B. Tab 160 may take many forms, including an inclined 
inwardly extending portion of flange 138, or a perpendicularly extending 
tab from the bottom edge of the flange. Groove 130 and tab 160 cooperate 
with one another to properly locate indicating ring member J relative to 
bonnet B for positioning certain indicia on ring member J in the proper 
location. 
As shown in FIG. 7, tab 160 is shown as simply comprising an inwardly 
inclined slit portion from circumferential flange 138. FIG. 8 shows tab 
160a as comprising a generally radially inward extending extension from 
the bottom end of inner flange 138. 
Referring to FIGS. 1 and 9, operating means H includes a pointer or 
indicator means 180 and a stop pin 182. Upon rotation of operating member 
H to its full open position, pointer or indicator means 180 will be 
aligned with an indicator line 184 on inclined surface 150 of indicating 
ring member J. In this position, stop pin 182 carried by head 60 will 
engage stop surface 124 (FIG. 5) for stopping rotation of the valve 
operating member in its full open position. In this position, coil spring 
40 moves valve member E axially upward in the view of FIG. 1 to its full 
open position wherein seal 38 is axially displaced from seat 36. 
When the valve is closed, handle 62, i.e., operating member H, is rotated 
clockwise in the view of FIG. 9 until pointer 180 is located in a closed 
normal angular range 202. This range is defined between radial lines 
204,206 arcuately spaced apart from each other by an angle of 
approximately 27.5.degree., with line 204 being located slightly less than 
90.degree. from line 184 and line 206 being located greater than 
90.degree. therefrom. An abnormal angular range generally indicated by 
numeral 208 extends between radial lines 206,210 over an angle of 
approximately 22.5.degree. adjacent range 202. In the preferred 
arrangement, area 202 is colored green between lines 204,206 to provide an 
arcuate band of one color for indicating a normal closed position for the 
valve when pointer 180 is aligned therewith. When seal 38 is unduly worn 
so that replacement thereof is or soon may be necessary, pointer 180 will 
overtravel beyond normal closed range 202 into abnormal angular range 208. 
Range 208 is colored red for indicating and alarming an operator that 
replacement of seal 38 is necessary. In the event seal 38 is substantially 
worn and a replacement seal is not immediately available, it is possible 
to temporarily readjust operating member H on stem G for permitting the 
seal to sealingly engage seat 36 in the valve closed condition. 
Cut-out end surface 122 (FIG. 5) is angularly spaced well beyond warning 
band 208 so that stop pin 182 (FIG. 1) on operating member H will not 
engage surface 122, even though pointer 180 is approaching travel beyond 
warning area 208. Adjacent contrasting color bands 202,208 are located on 
inclined surface 150 so they are readily visible in directions both 
parallel and perpendicular to longitudinal axis 152. 
It will be recognized that valve open position indicia 184 on ring member J 
has a predetermined angular relationship with locating means 160 and with 
indicating means 202,208. This relationship is such that assembly or 
disassembly of the valve always insures that indicating ring member J is 
installed in proper position because of the necessary alignment of 
locating means 130,160. This properly locates color bands 202,208 in the 
closed position of the valve member with respect to a rotatable valve 
operating member. 
It will also be recognized that the improved arrangement of the present 
application provides cooperating indicating means between operating member 
H and bonnet B for indicating overtravel of operating member H in its 
closed position to thereby indicate that replacement of seal 38 is 
required. In the arrangement shown and described, the indicating means 
takes the form of an indicator 180 on operating member H and indicating 
bands 202,208 on an indicating ring member J attached to bonnet B. 
However, it will be recognized that many other arrangements are possible 
without departing from the overall intent or scope of the invention. 
Furthermore, instead of merely indicating open and overtravel positions of 
an operating member, it will be appreciated that indicating ring member J 
can be used for many other purposes, including concealment of panel nut 
110 and the performance of other indicating functions having appropriate 
indicia thereon. 
The improved indicia arrangement of the present application indicates the 
open position of the valve, a normal angular range of closed positions, 
and an abnormal range of closed positions. Thus, the user of the valve can 
readily determine visually whether the valve is open, closed, or that the 
seal requires replacement. The simplified manner of attaching the 
indicator ring member to the valve bonnet makes it possible to easily 
remove and replace the valve, or to renew its components. The indicating 
ring member accommodates this capability by having locating means defined 
by cooperating groove 130 and tab 160 for properly positioning ring member 
J with its indicating bands 202,208 in the desired circumferential 
location. 
Although the invention has been shown and described with respect to certain 
preferred embodiments, modifications and alterations will occur to others 
skilled in the art upon a reading and understanding of this specification. 
It is intended to include all such modifications and alterations insofar 
as they come within the scope of the claims or the equivalents thereof.