FORM 2
THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10. rule 13) 1. Title of the invention: A FLOW MEASURING DEVICE
2. Applicant(s)

NAME NATIONALITY ADDRESS
RAYCHEM RPG PVT. LTD Indian RPG House 463, Dr. Annie Besant Road, Worli, Mumbai, Maharashtra 400 030, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

TECHNICAL FIELD
[0001] The present subject matter relates to devices for measuring a mass flow of a fluid flowing through an enclosed channel, such as a pipe.
BACKGROUND
[0002] A flow meter is a device which may be used to measure a volume of fluid which may be delivered through an enclosed channel, such as a pipe or a pipeline. Examples of fluids include, but are not limited to, gases such as natural gas and liquefied petroleum gas. Such flow meters, also referred to as gas flow meters, may be implemented for residential, commercial, and industrial facilities having a fuel gas supplied by a gas utility company. One example of such a flow measuring devices includes a diaphragm meter. A diaphragm meter is a positive displacement flow measurement instrument which is used to measure the volume of gas that passes through it, based on a stroke or movement of a diaphragm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The following detailed description references the drawings, wherein:
[0004] FIG. 1 depicts a block diagram of a flow measuring device, according to an
example;
[0005] FIG. 2 depicts a perspective view of a scotch yoke assembly of a flow
measuring device, according to an example; and
[0006] FIG. 3 depicts front and top views of a scotch yoke assembly of a flow
measuring device, according to an example.
DETAILED DESCRIPTION
[0007] A measure of flow rate of fluids is typically measured through flow measuring devices, such as a diaphragm meter. A diaphragm meter may include a plurality of measurement chambers formed by a plurality of moveable diaphragms. The diaphragms expand and contract, based on flow of fluid through the chambers. The movement of the diaphragms may be converted to a rotary motion of a crank shaft using a pantograph-based crank mechanism, which may then be used for driving a counter mechanism. The

counter mechanism may give an indication as to the volume of fluid which may have passed through.
[0008] The conventional diaphragm-based flow measuring device have a number of
limitations. The link mechanism which is to transfer the lateral motional of the diaphragm to a rotating shaft of the counter, are often complex. For example, conventional diaphragm meters include a pantograph based linking mechanism which eventually conveys the lateral motion of the diaphragm to the rotating shaft. Such a link includes a number of parts which adds to the complexity of the entire flow measuring device. Furthermore, having such complex linking mechanisms also tend to increase the size and bulk of the flow measuring device, thereby preventing such flow measuring devices to be used in compact spaces. It is also pertinent to note that a large number of mechanical parts may also tend to suffer from wear and tear, and may require periodic maintenance, which may involve costs. It might also be the case that, the mechanical approaches involved in conventional pantograph-crank based diaphragm meters may be inefficient while complying to the new standards of the flow measuring devices. Furthermore, owing to the complex constructional features involving a number of mechanical parts, the flow rate estimates may suffer from inaccuracy.
[0009] Examples of diaphragm-based flow measuring devices for determining a flow
rate of a fluid, are described. The flow measuring device includes an enclosed housing
along the channel, through which the fluid is to be transported. As would be generally
understood, the housing may include an inlet port and an outlet port. The housing may
include a diaphragm assembly, comprising a first diaphragm and a second diaphragm,
which may move laterally in a to-and-fro motion when the fluid flows through the housing.
A cam may further be coupled to the diaphragm assembly in such a manner, that the to-
and-fro movement of the diaphragm assembly may cause the cam to rotate. In one
example, the diaphragm assembly may include a first arm and a second arm coupled to
the first diaphragm and the second diaphragm respectively. The arms may be coupled
to the diaphragms in such a manner, that the to-and-fro movement of diaphragms may
cause the arms to move in a similar to-and-fro manner, thereby causing the cam to rotate.
[0010] The flow measuring device may further include a scotch yoke assembly,
coupled to the cam. The scotch yoke assembly, also referred to as slotted link mechanism, is to convert the rotational motion of the cam into a translational motion. The scotch yoke assembly may, in turn, be coupled to a first slider cover and a second slider cover. The scotch yoke assembly, along with other components, may be designed in

such a manner that based on the rotation of the cam, the scotch yoke assembly may cause the first and the second slider covers move to-and-fro. The slider covers may thereby cause the fluid to flow across a plurality of chambers of the diaphragm assembly in the housing.
[0011] The cam may further be coupled to a counter mechanism. The counter
mechanism is to measure the rotation of the cam, based on which the flow rate of the fluid flowing across the housing may be determined. The counter mechanism may be a mechanical-based counter or an electronic sensor-based counter. Examples of such counter mechanism may include, but are not limited to, a tachometer, a hall effect sensor, an inductive senor, and an optical type sensor.
[0012] In another example, the cam may be coupled to a rotatable shaft, such that the
rotation of cam may cause the shaft to rotate. The counter mechanism may then be coupled to the shaft, such that the counter mechanism may measure the rotation of the shaft. In yet another example, the cam may be coupled to the shaft, via a geared mechanism. The geared mechanism may rotate, based on the rotation of the cam, thereby causing the shaft to rotate. However, the cam may be coupled to the counter mechanism in any other way, without deviating from the scope of the present subject matter. In yet another example, the flow measuring device may be a self-energized device.
[0013] The present approaches provide numerous technical advantages over
previously known flow measuring devices. As would be appreciated, a scotch yoke-based mechanism for determining the flow rate of the fluid across the diaphragm assembly in a housing is likely to provide more accurate results when compared to flow rate values which may be determined through conventional pantograph-crank based mechanisms used in diaphragm meters. The flow measuring device as described involves a smaller number of components, and is less complicated as compared to previously known systems. Furthermore, the rotation of the cam, based on the movement of diaphragms may also be used for powering the different components, like counter mechanism and flow estimation unit that are provided within the flow measuring device. The flow measuring device is thus self-reliant and safe. It may be noted that the above approaches may be performed using a variety of other mechanisms or components. Such examples are further described in conjunction with FIGS. 1-3.
[0014] FIG. 1 illustrates a block diagram of a flow measuring device 100, according to
an example of the present subject matter. The flow measuring device 100 may be utilized

for determining a flow rate of a fluid which may be passing through an enclosed housing. The fluid may be a gas or a liquid. Examples of such fluids include, but are not limited to, air, natural gas and liquefied petroleum gas. The flow measuring device 100 may be utilized in industrial, commercial, or residential applications.
[0015] In an example, the flow measuring device 100 may be enclosed in a housing
(not shown in FIG. 1). The housing may be positioned along a channel (not shown in FIG. 1), transporting the fluid. As would be understood, the housing may include an inlet port and an outlet port. The inlet port allows the inflow of the fluid in the housing. The fluid is to flow through the housing, after which the fluid exits the housing through the outlet port. The inlet port and the outlet port are so adapted such that they may be extending outside the housing, and couplable to a supply of fluid. In an example, housing may be an enclosed container.
[0016] The flow measuring device 100 may include a diaphragm assembly 102, cam
104, scotch yoke assembly 106, first slider cover 108, second slider cover 110, and shaft
112. The diaphragm assembly 102 may include diaphragm(s) 114 and chamber(s) 116.
The housing may house the aforementioned components, along with other components
(not shown in FIG. 1) of the flow measuring device 100. In addition, the housing may also
secure and protect all the components from external conditions, and against tampering.
[0017] The diaphragm assembly 102 may be in communication with the fluid flowing
through the housing. The diaphragm assembly 102 may further include one or more diaphragms 114, such that the fluid on passing through the diaphragms 114, may result in the to-and-fro movement of the diaphragms 114. The cam 104 may be coupled to the diaphragm assembly 102 in such a manner, that to-and-fro movement of diaphragms 114 of the diaphragm assembly 102 may result in the rotation of cam 104.
[0018] The cam 104 may then be subsequently coupled to a scotch yoke assembly
106. The scotch yoke assembly 106, also referred to as a slotted link mechanism, may be used to convert the rotational motion of the cam 104 into a translational motion. The scotch yoke assembly 106, in turn, may be coupled to a first slider cover 108 and a second slider cover 110. Based on the rotation of the cam 104, the scotch yoke assembly 106 may cause the first slider cover 108 and the second slider covers 110 to move to-and-fro, causing the fluid to flow across a plurality of chambers 116 of the diaphragm assembly 102.
[0019] The cam 104 may further be coupled to a rotatable shaft 112, such that the
rotation of the cam 104 may cause the shaft 112 to rotate. The shaft 112 may further be

coupled to a counter mechanism (not shown in FIG. 1), such that the counter mechanism may measure the rotation of the shaft 112. In one example, the shaft 112 may be coupled to the cam 104 via a geared mechanism, in such a way that rotation of cam 104 may cause the gears to rotate, thereby causing the shaft 112 to rotate. Thereafter, the counter mechanism may measure the rotation of the shaft 112. In yet another example, the counter mechanism may be coupled directly to the cam 104, and the counter mechanism may measure the rotation of the cam 104. However, the cam 104 may be coupled to the counter mechanism in any other way, without deviating from the scope of the present subject matter.
[0020] Returning to the present example, the counter mechanism, based on the
measured rotation of the shaft 112, may determine a flow rate of the fluid flowing through the housing. The flow rate of the fluid may correspond to the kinetic energy possessed by the fluid while flowing across the diaphragm assembly 102 in the housing. The counter mechanism may be a mechanical-based counter or an electronic sensor-based counter. Examples of such counter mechanisms may include, but are not limited to, a tachometer, hall effect sensor, inductive sensor, and optical type sensor. However, these examples of counter mechanisms are only illustrative, and any other counter mechanism may be used without limiting the scope of the present subject matter.
[0021] In another example, the flow measuring device 100 may be a self-energized
device. The manner in which the flow rate of the fluid is estimated, is further described in detail in conjunction with FIG. 2.
[0022] FIG. 2 illustrates a perspective view of the scotch yoke assembly, along with
other components, for measuring the flow of fluid, according to an example of the present
subject matter. The components, as will be described below, may be a part of the flow
measuring device 100 as depicted in FIG. 1. The scotch yoke assembly 200 may be
positioned along with a diaphragm assembly (such as diaphragm assembly 102), in
communication with the fluid flowing within a housing of the flow measuring device 100.
[0023] As described previously, the cam 202 may be coupled to the diaphragm
assembly 102 of the flow measuring device 100 in such a manner, that the to-and-fro movement of the diaphragms 114 may cause the cam 202 to rotate. In one example, the diaphragms 114 may be coupled to a pair of arms, such that the to-and-from movement of diaphragms 114 may cause the arms to move in a similar to-and-fro manner. The arms, in turn, may be coupled to the cam 202 in such a manner that the movement of arms may cause the cam 202 to rotate.

[0024] Returning to the present example, a scotch yoke assembly may be further
coupled to the cam 202. The scotch yoke assembly, also referred to as a slotted link mechanism, may be used to convert a rotational motion into a translational motion. The scotch yoke assembly may include a pin 204, a slotted frame 206, a first connecting link 208-1, and a second connecting link 208-2.
[0025] The scotch yoke assembly may be designed in such a manner that the pin 204
may be passing through the slotted frame 206, and may be mounted on the cam 202. The slotted frame 206 may be a longitudinally extending frame, positioned diametrically along the cam 202, allowing the pin 204 to move along its length. The scotch yoke assembly may further include a first connecting link 208-1 and a second connecting link 208-2, coupled to and positioned in a direction perpendicularly opposite to the slotted frame 206. In the context of the present subject matter, the scotch yoke mechanism may convert the rotational motion of the cam 202 into a translational motion of the connecting links 208.
[0026] The first connecting link 208-1 may be coupled to a first slider cover 210-1 and
the second connecting link 208-2 may be coupled to a second slider cover 210-2. The
slider covers 210 may be in communication with an opening 212 of the chambers 116 of
the diaphragm assembly 102. The translational motion of the connecting links 208 may
then cause the slider covers 210 to move to-and-fro, thereby allowing the fluid to flow
across a plurality of chambers 116 of the diaphragm assembly 102 in the housing.
[0027] In operation, the fluid may be introduced in a housing of the flow measuring
device 100, via an inlet port. As described above, upon introduction of the fluid in the flow
measuring device 100, the diaphragms 114 may move to-and-fro, causing the arms to
move in a similar to-and-fro manner. The arms, in turn, may rotate the cam 202. The
scotch yoke assembly, via a plurality of components, may convert the rotational motion
of the cam 202 into translational motion of the first slider cover 210-1 and the second
slider cover 210-2, thereby causing the slider covers 210 to move to-and-fro.
[0028] The slider covers 210, when moved to-and-fro, may cause the fluid to flow
across a plurality of chambers 116 of the diaphragm assembly 102. The scotch yoke assembly may be positioned in such a manner that the to-and-fro movement of the slider covers 210 may alter the openings 212 of the chambers 116 of the diaphragm assembly 102 and may cause the fluid to flow across various chambers 116 of the diaphragm assembly 102. In one example, the lengths of the connecting links 208, coupling the slider covers 210 with other components of the flow measuring device 100, may be

chosen in such a manner, that may result in the opening and closing of the chambers 116 of diaphragm assembly 102 at different time instants
[0029] The cam 202 may further be coupled to a counter mechanism (not shown in
FIG. 2). The counter mechanism is to measure the rotation of the cam 202, based on
which the flow rate of the fluid flowing across the housing may be determined. The
counter mechanism may be a mechanical-based counter or an electronic sensor-based
counter. Examples of such counter mechanism may include, but are not limited to, a
tachometer, a hall effect sensor, an inductive senor, and an optical type sensor.
[0030] In another example, the cam 202 may be coupled to a rotatable shaft 214, such
that the rotation of cam 202 may cause the shaft 214 to rotate. The counter mechanism may then be coupled to the shaft 214, such that the counter mechanism may measure the rotation of the shaft 214. In yet another example, the cam 202 may be coupled to the shaft 214, via a geared mechanism. The geared mechanism may rotate, based on the rotation of the cam 202, thereby causing the shaft 214 to rotate. However, the cam 202 may be coupled to the counter mechanism in any other way, without deviating from the scope of the present subject matter. In yet another example, the flow measuring device 100 may be a self-energized device.
[0031] In this manner, the kinetic energy possessed by the fluid flowing across the
diaphragm assembly 102 in the housing of the flow measuring device 100 may impart the same in the form of translational energy to the diaphragms 114. The contraction and expansion of the diaphragms 114, i.e., the to-and-fro movement, along with the scotch yoke-based mechanism may then impart the translational energy to the cam 202 in the form of rotational energy, which may be measured by the counter mechanism.
[0032] FIGS. 3A and 3B depict front view and top view of the scotch yoke assembly
200 respectively, as described in FIG. 3. It may be noted that the above-mentioned example is only illustrative and is not to be considered as limiting the scope of the present subject matter.
[0033] Although examples for the present disclosure have been described in language
specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed and explained as examples of the present disclosure.

I/We Claim:
1. A flow measuring device comprising:
a diaphragm assembly comprising a first diaphragm and a second diaphragm, wherein the first and the second diaphragm are to move to-and-fro based on a transportation of a volume of fluid;
a cam coupled to the diaphragm assembly, wherein the cam is to rotate based on the to-and-fro movement of the first and the second diaphragm;
a scotch yoke assembly coupled to the cam, wherein the scotch yoke assembly is to move based on the rotation of cam;
a first slider cover and a second slider cover coupled to the scotch yoke assembly, wherein the first and the second slider covers are to move to-and-fro based on the movement of scotch yoke assembly; and
a counter mechanism coupled to the cam, wherein the counter mechanism is to measure the rotation of the cam.
2. The flow measuring device as claimed in claim 1, further comprising:
a rotatable shaft coupled to the cam, wherein the shaft is to rotate based on the rotation of the cam; and
the counter mechanism coupled to the shaft, wherein the counter mechanism is to measure the rotation of the shaft.
3. The flow measuring device as claimed in claim 1, wherein the flow measuring device is enclosed in a housing, wherein the housing comprises an inlet port and an outlet port for transporting a volume of fluid.
4. The flow measuring device as claimed in claim 1, wherein the diaphragm assembly further comprises a first arm and a second arm, wherein:
the first arm is to move to-and-fro, based on the movement of the first diaphragm; and
the second arm is to move to-and-fro, based on the movement of the second diaphragm.

5. The flow measuring device as claimed in claim 4, wherein the cam is to further rotate based on the to-and-fro movement of the first and the second arm.
6. The flow measuring device as claimed in claim 1, wherein the scotch yoke assembly is to convert a rotational motion of the cam into a translational motion of the first and the second slider covers.
7. The flow measuring device as claimed in claim 1, wherein the movement of the first and the second slider cover is to cause the volume of fluid to flow across a plurality of chambers of the diaphragm assembly.
8. The flow measuring device as claimed in claim 1, wherein the counter mechanism is to further:
based on the measured rotation of the cam, determine a flow rate of the volume of fluid flowing through the housing.
9. The flow measuring device as claimed in claim 1, wherein the counter mechanism is one of a mechanical-based counter and an electronic sensor-based counter.
10. The flow measuring device as claimed in claim 1, wherein flow measuring device is a self-energized device.