FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS (AMENDMENT) RULES, 2006
COMPLETE SPECIFICATION
[See Section 10; rule 13]
“DIAPHRAGM ASSEMBLY FOR A PUMP”
IDEX India Pvt. Ltd., an Indian company, of A unit of IDEX Corporation, Survey No 256, GIDC Manjusar, Savli, Near Bombardier Circle, District Vadodara - 391775, Gujarat, India,
The following specification particularly describes the invention and the manner in which it is to be performed:

DIAPHRAGM ASSEMBLY FOR A PUMP
FIELD OF THE INVENTION
[0001] The present invention relates to the field of pumps, and more specifically
to diaphragm assemblies of fluid pumps.
BACKGROUND OF THE INVENTION
[0002] A diaphragm pump is a positive displacement pump that uses a
combination of reciprocating action of a diaphragm and suitable valves to pump a fluid. Diaphragm pumps possess many advantages and are widely used. Diaphragm pumps may be pneumatically, hydraulically, or electrically operated.
[0003] In an Air-Operated Double Diaphragm (AODD) pump, two diaphragms
reciprocate back and forth, creating temporary chambers, which draw in and expel fluid through the pump. The diaphragms work as a separation wall between air and the fluid to be pumped. Two diaphragms are typically connected by a shaft through a centre section where an air valve is located. The purpose of the air valve is to direct compressed air to the diaphragms, to cause them to move away from the centre section. At an instance, the diaphragms perform a discharge stroke and a suction stroke, respectively, to move the fluid out of the pump. During suction stroke of any of the two diaphragms, air present behind the diaphragms is pushed out to the atmosphere causing atmospheric pressure to push the fluid to the suction side. During the suction stroke, a suction ball valve provided at an inlet of the pump is pushed away off its seat, to allow the fluid to flow past the suction ball valve, into a pumping chamber. Because AODD

pumps use compressed air as prime mover of their diaphragms, they have low efficiency of about 15% to 20%.
[0004] Electrically operated diaphragm pumps typically employ volumetric
positive displacement. Within such pumps, a prime mover of diaphragms is an electro-mechanical element, such as a crank or geared motor drive. Alternatively, the prime mover of the diaphragms of such pumps is a purely mechanical element, such as a lever or a handle. Upon being operated by a suitable prime mover, when a diaphragm moves away from a pumping chamber of the pump, volume of the pumping chamber increases, and pressure in the pumping chamber decreases. Due to the reduced pressure, fluid is drawn from a fluid source into the pumping chamber. When the diaphragm moves towards the pumping chamber, pressure in the pumping chamber increases, and the fluid that is drawn in previously is pumped out. Thereafter, the diaphragm moving away from the pumping chamber once again draws fluid into the chamber, thereby completing an operation cycle. With such manner of operation, the electro-mechanically operated pumps have higher efficiency than the AODD pumps.
[0005] In the above described manners, conventional diaphragm pumps employ
diaphragm assemblies to control flow of fluids. Such conventional diaphragm assemblies, implemented either on single or multiple piston rods, exist as single piece molded structures or multi-piece structures containing metallic inserts. Such conventional diaphragms assemblies typically include convoluted regions circumscribing a central pumping region. The convoluted regions continuously flex as the diaphragm assemblies are driven by piston rods or other suitable driving mechanisms. Convoluted regions of such conventional diaphragm assemblies have a tendency to get inverted (also known as reverse flipping) while experiencing negative pressure in suction strokes. Such inversion or reverse flipping of the conventional diaphragm assemblies result in reduced pump pressure, and therefore reduces

efficiency of the pumps. Occurrence of such reverse flipping increases with usage of the diaphragm assemblies, over a period of time. Moreover, such conventional diaphragm assemblies are prone to wear and development of cracks around piston rod bead, due to sharp metal contacts between different elements.
[0006] There is therefore a need in the art to provide a diaphragm assembly that
address above described deficiencies associated with conventional diaphragms.
OBJECTS OF THE INVENTION
[0007] An object of the present invention is to provide a diaphragm assembly for
a pump, which does not suffer from reverse flipping, in negative pressure conditions.
[0008] Another object of the present invention is to provide a diaphragm assembly
for a pump, which does not contain metal inserts.
[0009] Another object of the present invention is to prevent development of cracks
on surface of a diaphragm assembly for pumps, and thus improving operational life of the diaphragm assembly.
[00010] Another object of the present invention is to provide a diaphragm assembly
which maintains a uniform pressure, during operation of a pump utilizing the diaphragm assembly.
[00011] Still another object of the present invention is to provide a diaphragm
assembly which improves efficiency of a pump.

SUMMARY OF THE INVENTION
[00012] The present invention relates to a diaphragm assembly for a pump used for
pumping fluids, such as an Electrically Operated Double Diaphragm (EODD) pump. The diaphragm assembly prevents formation of cracks on surfaces of a diaphragm and further prevents flipping of the diaphragm during negative pressure conditions, such as during suction strokes. The diaphragm assembly also maintains a uniform pump pressure throughout operation of the pump, and improves efficiency of the pump.
[00013] The diaphragm assembly includes a piston plate configured to face a piston
rod disposed towards an air chamber of the pump, a diaphragm plate configured to face a pumping chamber of the pump and having a projected surface disposed at a periphery thereof, and a diaphragm configured to operatively couple with a mounting portion of the pump. The diaphragm is disposed between the diaphragm plate and the piston plate, and includes a bent portion projecting away from the diaphragm plate. The bent portion of the diaphragm may have a concave profile, a triangular profile, a pyramidal profile, a square profile, or a rectangular profile. In a preferred embodiment, the bent portion of the diaphragm has the concave profile, which may also be referred as an arcuate profile, a C-shaped profile, and a U-shaped profile, based on a degree of concavity of the bent portion. The diaphragm also includes a beaded portion for being clamped within the mounting portion of the pump. Further, the projected surface of the diaphragm plate extends towards the bent portion of the diaphragm. The diaphragm plate and the piston plate are made using aluminium, cast iron, ductile iron, steel, stainless steel, duplex steel, Monel metal, Nickel alloy, plastic, or an elastomer. The diaphragm is made using a composite elastomer including rubber, Santoprene, plastic, and nylon fabric.

[00014] According to an embodiment of the present invention, the diaphragm plate,
the diaphragm, and the piston plate are fastened with each other using fasteners passing through a plurality of threaded slots present around the holes of the diaphragm plate and the piston plate.
[00015] According to an embodiment of the present invention, one or more of the
diaphragm plate and the piston plate includes threads on their central holes for locking with threads present around the piston rod. Further, a stepped portion of the piston rod abuts against the piston plate. The piston rod is a part of a linear reciprocating mechanism and imparts reciprocating motion to the diaphragm assembly.
[00016] According to an embodiment of the present invention, a diameter of the
central hole of the diaphragm plate is lesser than or equal to a diameter of the central hole of the piston plate when a stepped portion of the piston rod abuts against the diaphragm plate.
[00017] According to an embodiment of the present invention, an unsupported
length (L1) of lateral ends of the diaphragm assembly is present towards the pumping chamber of the pump and between a proximal end of the mounting portion and the projected surface. Further, an unsupported length (L2) of lateral ends of the diaphragm assembly is present towards the piston rod of the pump and between a distal end of the mounting portion and a periphery of the piston plate. In one implementation, the unsupported length (L1) may range from 2.5% to 35% of a diameter of the diaphragm (114) and the unsupported length (L2) may range from 2.5% to 35% of the diameter of the diaphragm (114). In a preferred embodiment, the unsupported length (L1) may range from 2.5% to 7.5% of the diameter of the diaphragm (114) and the unsupported length (L2) may range from 5% to 15% of the diameter of the diaphragm (114). The unsupported length (L1) is smaller than the unsupported length (L2).

[00018] According to an embodiment of the present invention, the diaphragm
assembly has a high diameter to stroke length ratio ranging from 4:1 to 12:1. In a preferred embodiment, the diaphragm assembly has a high diameter to stroke length ratio ranging from 8:1 to 12:1.
[00019] According to an embodiment of the present invention, the diaphragm may
be made up of a composite elastomer, such as rubber and nylon fabric. The diaphragm may be covered with a protective layer, at least towards the pumping chamber, to prevent damage from chemicals pumped by the pump. The protective layer may be made up of a chemical resistant material such as plastic.
BRIEF DESCRIPTION OF THE DRAWINGS
[00020] The accompanying drawings are included to provide a further
understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[00021] Fig. 1 illustrates an exemplary sectional view of a diaphragm assembly of
a pump, in accordance with an embodiment of the present invention.
[00022] Fig. 2A illustrates exemplary representations of a front surface and a rear
surface of a diaphragm plate of the diaphragm assembly, in accordance with an embodiment of the present invention.

[00023] Fig. 2B illustrates exemplary representations of a front surface and a rear
surface of a piston plate of the diaphragm assembly, in accordance with an embodiment of the present invention.
[00024] Fig. 2C illustrates an exemplary representation of a piston rod of the pump,
in accordance with an embodiment of the present invention.
[00025] Fig. 3 illustrates a profile of a stepped portion of a piston plate, in
accordance with another embodiment of the present invention.
[00026] Figs. 4A through 4C illustrate exemplary representations of the diaphragm
plate and the piston plate having various shapes, in accordance with different embodiments of the present invention.
[00027] Fig. 5 illustrates an exemplary sectional view of the diaphragm assembly
installed in an electrically-operated double diaphragm pump, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[00028] As used in the description herein and throughout the claims that follow, the
meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[00029] Exemplary embodiments will now be described more fully hereinafter with
reference to the accompanying drawings, in which exemplary embodiments are shown. This disclosure may however, be embodied in many different forms and should not be

construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).
[00030] The present invention relates to a diaphragm assembly for a pump. The
diaphragm assembly is designed to avoid reverse flipping, prone to development of cracks, and therefore has a prolonged service life. Usage of such diaphragm assembly improves efficiency of the pump by maintaining a uniform pump pressure, during operation of the pump.
[00031] Fig. 1 illustrates a sectional view representation of a diaphragm assembly
(100) installed in a (fluid) pump, in accordance with an embodiment of the present invention. The diaphragm assembly (100) may be installed in the pump for pumping a particular a fluid, such as water, oil, and a chemical. The fluid may be drawn into and pumped out of a pumping chamber (102) of the pump. A predetermined volume of the fluid may be drawn into the pumping chamber (102) during a suction stroke of the diaphragm assembly (100). The suction stroke of the diaphragm assembly (100) may refer to a condition in which pressure in the pumping chamber (102) decreases. Subsequently, the fluid may be pumped out of the pumping chamber (102), to an outlet of the pump, during a discharge stroke of the diaphragm assembly (100). The discharge stroke of the diaphragm assembly (100) may refer to a condition in which pressure in the pumping chamber (102) increases.

[00032] On one side, the diaphragm assembly (100) may be connected with a piston
rod (104) present towards an air chamber of the pump. The piston rod (104) may be operatively coupled with a linear reciprocating mechanism (as clearly shown in Fig. 4 and described in later paragraphs). The piston rod (104) may transfer a reciprocating motion of the linear reciprocating mechanism to the diaphragm assembly (100), in order to attain suction and discharge strokes of the diaphragm assembly (100).
[00033] According to an embodiment of the present invention, the diaphragm
assembly (100) may include a diaphragm plate (106), also illustrated in Fig. 2A. Specifically, Fig. 2A shows exemplary representations of a front surface and a rear surface of the diaphragm plate (106). The diaphragm plate (106) may face the pumping chamber (102). The diaphragm plate (106) has a projected surface (106a) disposed at a periphery thereof. It must be understood that the projected surface (106a) extends to entire periphery of the diaphragm plate (106), in a continuous manner. The diaphragm plate (106) may include a central hole (108a) on its rear surface and a plurality of threaded slots (110a) arranged around the central hole (108a). In one implementation, the plurality of threaded slots (110a) may circumscribe the central hole (108a).
[00034] The diaphragm assembly (100) may also include a piston plate (112), as
also illustrated in Fig. 2B. Specifically, Fig. 2B shows exemplary representations of a front surface and a rear surface of the piston plate (112). The piston plate (112) may face the piston rod (104) disposed towards the air chamber of the pump. Further, the piston plate (112) may have a central threaded hole (108b) and a plurality of threaded slots (110b) arranged around the central hole (108b). In one implementation, the plurality of threaded slots (110b) may circumscribe the central hole (108b). The plurality of threaded slots (110b) present on the piston plate (112) may have dimensions similar to the plurality of threaded slots (110a) present on the diaphragm plate (106).

Preferably, a diameter of the piston plate (112) may be smaller than a diameter of the diaphragm plate (106).
[00035] The diaphragm assembly (100) may include a diaphragm (114) disposed
between the diaphragm plate (106) and the piston plate (112). Referring again to Fig. 2A, a serrated portion (202) may be provided on a rear surface of the diaphragm plate (106) to prevent slippage between the diaphragm plate (106) and the diaphragm (114), during operation of the diaphragm (100). The serrated portion (202) also prevents ingress of fluid between the diaphragm plate (106) and the diaphragm (114). As an additional measure, to prevent ingress of fluid between the diaphragm plate (106) and the diaphragm (114), a plurality of beads may also be disposed at a rear surface of the diaphragm plate (106)). The diaphragm (114) may be covered with a protective layer, at least towards the pumping chamber (102), to prevent damage from chemicals pumped by the pump.
[00036] The diaphragm (114) may include a central hole and a plurality of threaded
slots arranged around the central hole. In one implementation, the plurality of threaded slots present on the diaphragm (114) may circumscribe the central hole of the diaphragm (114). Further, the plurality of threaded slots present on the diaphragm (114) may have dimensions similar to the plurality of threaded slots (110a) present on the diaphragm plate (106) and the plurality of threaded slots (110b) present on the piston plate (112). The plurality of threaded slots (110a) present on the diaphragm plate (106), the plurality of threaded slots (110b) present on the piston plate (112), and the plurality of threaded slots present on the diaphragm (114) may henceforth be collectively referred as threaded slots (110).
[00037] The diaphragm plate (106), the diaphragm (114), and the piston plate (112)
may be coupled with each other using fasteners, such as threaded bolts, screws, and

threaded pins. The fasteners may pass through the threaded slots (110), to transmit forces from the diaphragm plate (106) to the piston plate (112) and vice versa i.e. from the piston plate (112) to the diaphragm plate (106).
[00038] The central hole (108a) present on the diaphragm plate (106), the central
hole present on the diaphragm (114), and the central hole (108b) present on the piston plate (112) may henceforth be collectively referred as central holes (108). The central holes (108) may contain internal threads for locking with threads present around the piston rod (104). The piston rod (104), operatively coupled to the linear reciprocating mechanism, may pass through the central holes (108).
[00039] The diaphragm plate (106) and the piston plate (112) may be made up of a
metal, alloy, plastic, or an elastomer, depending on load requirements of the diaphragm assembly (100). Metals and alloys that may preferably be used to fabricate the diaphragm plate (106) and the piston plate (112) may include aluminium, cast iron, ductile iron, steel, stainless steel, duplex steel, Monel metal, and Nickel alloy. Plastics preferably used to fabricate the diaphragm plate (106) and the piston plate (112) may include, but not be limited to, Polytetrafluoroethylene (PTFE), Polyvinylidene Fluoride (PVDF), and Polyphenylene Ether (PPE). The diaphragm (114) may be made up of a composite elastomer including rubber, Santoprene, plastic, and nylon fabric, such as rubber and nylon fabric. The protective layer covering the diaphragm (114) may be made up of a chemical resistant material such as plastic.
[00040] Referring now to Fig. 2C, the piston rod (104) may have a threaded face
(252) allowing coupling of the piston rod (104) with the linear reciprocating mechanism. The piston rod (104) may also have a sliding face (254) for sliding in a sleeve-bush arrangement, by action of the linear reciprocating mechanism. The piston rod (104) may have at least one stepped portion (256) to abut against the piston plate

(112) of the diaphragm assembly (100). A profile of the stepped portion (256) may vary in different implementations. For example, a first profile of the stepped portion (256) could be observed in Fig. 1. In the first profile, the diameter of the central hole (108a) present on the diaphragm plate (106) is similar to the diameter of the central hole (108b) present on the piston plate (112). Further, the stepped portion (256) of the piston rod (104) abuts against the rear surface of the piston plate (112).
[00041] An alternate profile i.e. a second profile of the stepped portion (256) of the
piston rod (104) could be seen in Fig. 3. In the second profile, the diameter of the central hole (108a) present on the diaphragm plate (106) is lesser than the diameter of the central hole (108b) present on the piston plate (112), to support large axial loads during movement of the diaphragm assembly (100). Further, the stepped portion (256) abuts against the rear surface of the diaphragm plate (106). Such a configuration allows transfer of forces from the piston plate (112) to the diaphragm plate (106) and from the diaphragm plate (106) to the piston rod (104).
[00042] In an alternate embodiment, the piston rod (104) may have a female
threaded portion and any of the diaphragm plate (106) or the piston plate (112) may have a male threaded portion. The male threaded portion present on the diaphragm plate (106) or the piston plate (112) would couple with the female threaded portion of the piston rod (104), to support large axial loads during movement of the diaphragm assembly (100). Such configuration would allow transfer of forces from the diaphragm plate (106) or the piston plate (112) to the piston rod (104) and vice versa. Additionally, the piston rod (104) may include a stepped portion to support the large axial loads during movement of the diaphragm assembly (100).

[00043] In a preferred embodiment, the stepped portion (256) of the piston rod
(104) may have a threaded portion to mate with internal threads of the central holes (108), present on the diaphragm plate (106) and the piston plate (112).
[00044] A stacked arrangement of the diaphragm plate (106), the piston plate (112),
and the diaphragm (114) allows to prevent usage of metal inserts in the diaphragm assembly (100). Such stacked arrangement also prevents formation of cracks on surfaces of any of the diaphragm plate (106), the piston plate (112), and the diaphragm (114), thereby prolonging operational life of the diaphragm assembly (100).
[00045] Referring back to Fig. 1, the diaphragm (114) may include a beaded portion
(114b) at a periphery, to allow coupling/clamping of the diaphragm (114) with the mounting portion (116) of the pump. The beaded portion (114b) enables sealing between the diaphragm (114) and the mounting portion (116) of the pump, to prevent ingress of fluid into the mounting portion (116). The mounting portion (116) may have a proximal end (116a) and a distal end (116b). In different implementations, the beaded portion (114b) may have suitable shapes for clamping with the mounting portion (116), such as a bulbous, a flat plated, and an anchor shape. The mounting portion (116) may have rounded surfaces having big generic radius making contact with the beaded portion (114b) of the diaphragm (114). Such design of the mounting portion (116) may prevent sharp metal-to-metal contact between the beaded portion (114b) and the mounting portion (116), and wearing of the beaded portion (114b) and, thereby prolonging operational life of the diaphragm assembly (100).
[00046] The diaphragm (114) includes a bent portion (114a) projecting away from
the diaphragm plate (106). Although the bent portion (114a) is shown to have a concave profile in Fig. 1, as a suitable implementation, the bent portion (114a) may also have other profiles, such as a triangular/ conical profile, pyramidal/ frustum profile, square

profile, and a rectangular profile. The concave profile may also be referred as an arcuate profile, a C-shaped profile, and a U-shaped profile, based on a degree of concavity of the bent portion. In a region proximal to the bent portion (114a) of the diaphragm (114), one or both of the diaphragm plate (106) and the piston plate (112) may contain rounded portions having big generic radii, to prevent development of cracks due to sharp metal-to-metal contact.
[00047] As illustrated in Fig. 1, the distal end (116b) of the mounting portion (116)
of the pump may include a relieving groove (118). The relieving groove (118) prevents the diaphragm (114) from coming into contact with a back chamber of the distal end (116b) of the mounting portion (116), during a suction stroke of the diaphragm assembly (100). At high pressures, the diaphragm (114) bulges out and may make contact the back chamber at the location where the relieving groove (118) is located. If significant contact is made between the diaphragm (114) (which is made of a soft material) and the back chamber (which is made of a hard material), the diaphragm (114) may wear out and/or may tear-off. Such wearing out or tearing of the diaphragm (114) is therefore prevented by the relieving groove (118).
[00048] In one implementation, the projected surface (106a) of the diaphragm plate
(106) may extend towards the bent portion (114a) of the diaphragm (114). Such a configuration of the bent portion (114a) of the diaphragm (114) and the projected surface (106a) present at a periphery (outer) of the diaphragm plate (106) prevents flipping of the diaphragm assembly (100). Particularly, flipping of the diaphragm assembly (100) is prevented by reducing an unsupported length (L1) of lateral ends of the diaphragm assembly (100), present between the proximal end (116a) of the mounting portion (116) and the projected surface (106a) of the diaphragm plate (106), to about 2.5% to 35% of diameter of the diaphragm (114). Preferably, the unsupported length (L1) is maintained from 2.5% to 7.5% of diameter of the diaphragm (114). It

should be noted that the unsupported length (L1) is present towards the pumping chamber (102). Another crucial design factor responsible for avoiding flipping of the diaphragm assembly (100) includes an unsupported length (L2) of lateral ends of the diaphragm assembly (100), present between the distal end (116b) of the mounting portion (116) and a periphery of the piston plate (112), being kept around 2.5% to 35% of diameter of the diaphragm (114). Preferably, the unsupported length (L2) is maintained from 5% to 15% of diameter of the diaphragm (114). The unsupported length (L1) is always kept smaller than the unsupported length (L2). It is to be noted that a large unsupported length (L2) allows for large strokes of the diaphragm assembly (100). A small unsupported length (L1) compared to the unsupported length (L2) prevents the diaphragm (114) from inverting and prevents the material of the diaphragm (114) to go into severe alternating stress loading. Similarly, low values of the unsupported lengths (L1 & L2) allows for small stroke length of the diaphragm assembly (100). To this effect, small stroke lengths can result in significant increase in life of the diaphragm (114).
[00049] In operation, during a suction stroke of the diaphragm assembly (100),
while the diaphragm assembly (100) moves away from the pumping chamber (102), by action of the piston rod (104), pressure inside the pumping chamber (102) decreases, and a predetermined volume of fluid is drawn into the pumping chamber (102). Such suction stroke of the diaphragm assembly (100) engenders negative pressure in the pumping chamber (102) which, under typical circumstances, has a tendency to flip/invert the diaphragm assembly (100) in a direction towards the pumping chamber (102). Under such operating conditions, the proposed design factors the diaphragm assembly (100), including the bent portion (114a) of the diaphragm (114), the projected surface (106a) of the diaphragm plate (106), and the defined unsupported lengths (L1 and L2), would prevent inversion of the diaphragm assembly (100) in the direction opposite to the pumping chamber (102). The pumping chamber (102) may have a

shallow design to draw extra dead volume of the fluid to reach maximum dry suction lift during operation of the pump.
[00050] Additionally or alternatively, the diaphragm assembly (100) may be
designed to have a large overall diameter and a small stroke length, to prevent inversion of the diaphragm assembly (100), during negative pressure conditions. In certain implementations, the diameter to stroke length ratio of the diaphragm assembly (100) may be kept around 4:1 to 12:1. Configuring the diaphragm assembly (100) to operate within the above defined diameter to stroke length ratio would improve the operational life of the diaphragm assembly (100). In preferred implementations, the diameter to stroke length ratio of the diaphragm assembly (100) would range from 8:1 to 12:1. Implementing such high diameter to stroke length ratio increases service life of the diaphragm assembly (100). Specifically, at high operating pressure of the pump, for instance, at 6bar, the diaphragm assembly (100) has a service life of more than 1500 hours.
[00051] Thereafter, during a discharge stroke of the diaphragm assembly (100),
while the diaphragm assembly (100) moves towards the pumping chamber (102), by action of the piston rod (104), pressure inside the pumping chamber (102) increases and the fluid accommodated in the pumping chamber (102) is pumped to the outlet of the pump, via a check-valve assembly.
[00052] As shown in Fig. 4A, ends of the diaphragm plate (106) and the piston plate
(112) may have a cylindrical/ straight shape or a conical/slant shape, near to the bent portion (114a) of the diaphragm (114). The proximal end (116a) of the mounting structure (116) may also have a cylindrical or conical/arcuate profile. Further, concavity of ends of the piston plate (112) may vary in different implementations. In one implementation, as illustrated in Fig. 4B, ends of the piston plate (112) may have

a conical shape. The conical shape of ends of the piston plate (112) provides extended support to the diaphragm (114) upon action of high pressures. In another implementation, as illustrated in Fig. 4C, ends of the piston plate (112) may have an inverse conical shape. The inverse conical shape of ends of the piston plate (112) reduces contact area between the piston plate (112) and the diaphragm (114), and thus reduces wear and tear of the diaphragm (114) due to friction with the piston plate (112).
[00053] Fig. 5 illustrates an exemplary sectional view of the diaphragm assembly
(100) installed in an Electrically-Operated Double Diaphragm (EODD) pump (500), in accordance with an embodiment of the present invention. Although illustrated to be installed in the EODD pump as an example, the diaphragm assembly (100) may be used in any other diaphragm pump, such as an air-operated diaphragm pump, a hydraulic-operated diaphragm pump, a mechanically operated diaphragm pump, or an electro-mechanically operated diaphragm pump.
[00054] Typically, the EODD pump (500) may employ two diaphragm assemblies
(100-1, 100-2), each constituting components of the diaphragm assembly (100) described above. The diaphragm assemblies (100-1, 100-2) may be operatively coupled with a linear reciprocating drive (502), via piston rod assemblies (104-1, 104-2), such that during a suction stroke of the diaphragm assembly (100-1), the diaphragm assembly (100-2) performs a discharge stroke, and vice versa. The piston rod assemblies (104-1, 104-2) may constitute to the piston rod (104) described above. Further, the linear reciprocating drive (502) may correspond to a mechanism capable of providing a reciprocating motion to the piston rod assemblies (104-1, 104-2). The linear reciprocating drive (502) may be implemented using suitable mechanism, such as a scotch-yoke mechanism, a reciprocating gear drive mechanism, a slider-crank mechanism, and a reciprocating-rotary drive.

[00055] In the above detailed description, reference is made to the accompanying
drawings that form a part thereof, and illustrate the best mode presently contemplated for carrying out the invention. However, such description should not be considered as any limitation of scope of the present invention. The structure thus conceived in the present description is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence.

We Claim:
1. A diaphragm assembly (100) for a pump, comprising:
a piston plate (112) configured to face a piston rod (104) disposed towards an air chamber of the pump;
a diaphragm plate (106) configured to face a pumping chamber (102) of the pump and having a projected surface (106a) disposed at a periphery thereof; and
a diaphragm (114) configured to operatively couple with a mounting portion (116) of the pump,
wherein the diaphragm (114) is disposed between the diaphragm plate (106) and the piston plate (112), and comprises a bent portion (114a) projecting away from the diaphragm plate (106), and
the projected surface (106a) of the diaphragm plate (106) extends towards the bent portion (114a) of the diaphragm (114).
2. The diaphragm assembly (100) as claimed in claim 1, wherein the pump is a mechanically operated diaphragm pump.
3. The diaphragm assembly (100) as claimed in claim 2, wherein the pump is an Electrically Operated Double Diaphragm (EODD) pump.
4. The diaphragm assembly (100) as claimed in claim 1, wherein one or more of the diaphragm plate (106) and the piston plate (112) comprises threads on their central holes (108a, 108b) for locking with threads present around the piston rod (104).
5. The diaphragm assembly (100) as claimed in claim 4, wherein the diaphragm plate (106), the diaphragm (114), and the piston plate (112) are fastened with each other

using fasteners passing through a plurality of threaded slots (110) present around the central holes (108a, 108b).
6. The diaphragm assembly (100) as claimed in claim 1, wherein a stepped portion of the piston rod (104) abuts against the piston plate (112).
7. The diaphragm assembly (100) as claimed in claim 1, wherein a stepped portion of the piston rod (104) abuts against the diaphragm plate (106).
8. The diaphragm assembly (100) as claimed in claim 1, wherein the piston rod (104) is a part of a linear reciprocating mechanism and imparts reciprocating motion to the diaphragm assembly (100).
9. The diaphragm assembly (100) as claimed in claim 4, wherein a diameter of the central hole (108a) of the diaphragm plate (106) is lesser than or equal to a diameter of the central hole (108b) of the piston plate (112), and wherein a stepped portion of the piston rod (104) abuts against the diaphragm plate (112).
10. The diaphragm assembly (100) as claimed in claim 1, wherein an unsupported length (L1) of lateral ends of the diaphragm assembly (100) is present towards the pumping chamber (102) of the pump and between a proximal end (116a) of the mounting portion (116) and the projected surface (106a), and an unsupported length (L2) of lateral ends of the diaphragm assembly (100) is present towards the piston rod (104) of the pump and between a distal end (116b) of the mounting portion (116) and a periphery of the piston plate (112).

11. The diaphragm assembly (100) as claimed in claim 10, wherein the unsupported length (L1) ranges from 2.5% to 35% of a diameter of the diaphragm (114) and the unsupported length (L2) ranges from 2.5% to 35% of the diameter of the diaphragm (114).
12. The diaphragm assembly (100) as claimed in claim 10, wherein the unsupported length (L1) is smaller than the unsupported length (L2).
13. The diaphragm assembly (100) as claimed in claim 1, wherein the bent portion (114a) of the diaphragm (114) has one of a concave profile, a triangular profile, a pyramidal profile, a square profile, and a rectangular profile.
14. The diaphragm assembly (100) as claimed in claim 1, wherein the diaphragm (114) comprises a beaded portion (114b) for being clamped within the mounting portion (116) of the pump.
15. The diaphragm assembly (100) as claimed in claim 1, wherein the diaphragm assembly (100) has a diameter to stroke length ratio ranging from 4:1 to 12:1.
16. The diaphragm assembly (100) as claimed in claim 1, wherein the distal end (116b) of the mounting portion (116) of the pump includes a relieving groove (118) to prevent the diaphragm (114) from coming into contact with a back chamber of the distal end (116b) of the mounting portion (116), during a suction stroke of the diaphragm assembly (100).
17. The diaphragm assembly (100) as claimed in claim 1, wherein the diaphragm plate (106) and the piston plate (112) are made using a material selected from a group

consisting of aluminium, cast iron, ductile iron, steel, stainless steel, duplex steel, Monel metal, Nickel alloy, plastic, and an elastomer.
18. The diaphragm assembly (100) as claimed in claim 1, wherein the diaphragm (114) is made using a composite elastomer including rubber, Santoprene, plastic, and nylon fabric.
19. The diaphragm assembly (100) as claimed in claim 1, wherein ends of the diaphragm plate (106) has one of a cylindrical shape and a conical shape near to the bent portion (114a) of the diaphragm (114).
20. The diaphragm assembly (100) as claimed in claim 1, wherein ends of the piston plate (112) has one of a cylindrical shape, a conical shape, and an inverse conical shape.
21. The diaphragm assembly (100) as claimed in claim 1, wherein the proximal end (116a) of the mounting structure (116) has one of a cylindrical profile and a conical profile.
22. The diaphragm assembly (100) as claimed in claim 1, wherein a protective layer covers the diaphragm (114), at least towards the pumping chamber (102), to prevent damage from chemicals pumped by the pump.
23. A diaphragm assembly (100) for a pump, comprising:
a piston plate (112) configured to face a piston rod (104) disposed towards an air chamber of the pump;
a diaphragm plate (106) configured to face a pumping chamber (102) of the pump and having a projected surface (106a) disposed at a periphery thereof; and

a diaphragm (114) configured to operatively couple with a mounting portion (116) of the pump,
wherein the diaphragm (114) is disposed between the diaphragm plate (106) and the piston plate (112), and comprises a bent portion (114a) projecting away from the diaphragm plate (106), and the projected surface (106a) of the diaphragm plate (106) extends towards the bent portion (114a) of the diaphragm (114),
and wherein an unsupported length (L1) of lateral ends of the diaphragm assembly (100) is present towards the pumping chamber (102) of the pump and between a proximal end (116a) of the mounting portion (116) and the projected surface (106a), and an unsupported length (L2) of lateral ends of the diaphragm assembly (100) is present towards the piston rod (104) of the pump and between a distal end (116b) of the mounting portion (116) and a periphery of the piston plate (112).