CN114651127A

CN114651127A - Diaphragm assembly for a pump

Info

Publication number: CN114651127A
Application number: CN202180005922.XA
Authority: CN
Inventors: J·维亚斯; K·马哈拉特卡
Original assignee: Adas India Pte Ltd
Current assignee: Adas India Pte Ltd
Priority date: 2020-10-21
Filing date: 2021-08-27
Publication date: 2022-06-21
Anticipated expiration: 2041-08-27
Also published as: CN114651127B; WO2022085018A1

Abstract

The invention relates to a diaphragm assembly (100) for a fluid pump. The diaphragm assembly includes: a piston plate (112) facing the piston rod (104), the piston rod (104) being disposed towards an air chamber of the pump; a diaphragm plate (106) facing a pumping chamber (102) of the pump and having a protruding surface (106a) provided at an edge thereof; and a diaphragm (114) operatively connected to the mounting portion (116) of the pump. The diaphragm (114) is disposed between the diaphragm plate (106) and the piston plate (112), and includes a curved portion (114a) that protrudes away from the diaphragm plate (106). The protruding surface (106a) of the diaphragm plate (106) extends toward the curved portion (114a) of the diaphragm (114). This arrangement of the diaphragm assembly (100) prevents reverse tipping under negative pressure conditions, thus increasing its useful life.

Description

Diaphragm assembly for a pump

Technical Field

The present invention relates to the field of pumps, and more particularly to diaphragm assemblies for fluid pumps.

Background

A diaphragm pump is a positive displacement pump that uses a combination of reciprocating movement of the diaphragm and appropriate valves to pump fluid. Diaphragm pumps have many advantages and are widely used. The diaphragm pump may be pneumatic, hydraulic or electric.

In an Air-Operated Double Diaphragm (AODD) pump, two diaphragms reciprocate back and forth to form a temporary chamber through which fluid is drawn and expelled. The membrane acts as a separating wall between the air and the fluid to be pumped. The two diaphragms are usually connected by a shaft through the central portion where the air valve is located. The purpose of the air valve is to direct compressed air towards the diaphragm away from the central portion. In one example, the diaphragm performs a discharge stroke and a suction stroke, respectively, to move fluid out of the pump. During the intake stroke of either of the two diaphragms, air behind the diaphragm is pushed out to the atmosphere, causing atmospheric pressure to push fluid toward the intake side. During the intake stroke, an intake ball valve disposed at the pump inlet is pushed off its seat to allow fluid to flow through the intake ball valve into the pumping chamber. Since AODD pumps use compressed air as their prime mover for the diaphragm, they are relatively inefficient, approximately 15% to 20%.

Electric diaphragm pumps typically employ positive displacement volumes. In such pumps, the prime mover of the diaphragm is an electromechanical element, such as a crank or gear motor drive. Alternatively, the prime mover of the diaphragm of such a pump is a purely mechanical element, such as a lever or handle. When operated by a suitable prime mover, as the diaphragm moves away from the pumping chamber of the pump, the volume of the pumping chamber increases and the pressure in the pumping chamber decreases. As a result of the pressure drop, fluid is drawn into the pumping chamber from the fluid source. As the diaphragm moves toward the pumping chamber, the pressure in the pumping chamber increases and the previously aspirated fluid is pumped out. Thereafter, the diaphragm, moving away from the pumping chamber, again draws fluid into the pumping chamber, thereby completing the operating cycle. In this way the efficiency of the electromechanically operated pump is higher than that of the AODD pump.

In the above manner, conventional diaphragm pumps employ a diaphragm assembly to control the flow of fluid. Such conventional diaphragm assemblies implemented on single or multiple piston rods exist as a single-piece molded structure or as a multi-piece structure containing metal inserts. Such conventional diaphragm assemblies typically include a convoluted region surrounding a central pumping region. The convoluted region continuously flexes as the diaphragm assembly is driven by the piston rod or other suitable drive mechanism. The convoluted region of such conventional diaphragm assemblies has a tendency to invert (also referred to as reverse roll-over) when subjected to negative pressure during the intake stroke. This inversion or reverse inversion of the conventional diaphragm assembly results in a reduced pumping pressure and therefore reduced pump efficiency. The occurrence of such reverse inversion increases over time as the diaphragm assembly is used. Furthermore, such conventional diaphragm assemblies are prone to wear and crack around the raised seal of the piston rod end due to sharp metal contact between the various elements.

Accordingly, there is a need in the art to provide a diaphragm assembly that addresses the above-described deficiencies associated with conventional diaphragms.

Object of the Invention

It is an object of the present invention to provide a diaphragm assembly for a pump that does not reverse under negative pressure conditions.

It is another object of the present invention to provide a diaphragm assembly for a pump that does not contain a metal insert.

It is another object of the present invention to prevent cracks from being generated on the surface of a diaphragm assembly for a pump, thereby improving the lifespan of the diaphragm assembly.

It is another object of the present invention to provide a diaphragm assembly that maintains a uniform pressure during operation of a pump in which the diaphragm assembly is used.

It is a further object of the present invention to provide a diaphragm assembly that improves the efficiency of the pump.

Disclosure of Invention

The present invention relates to a diaphragm assembly for a pump for pumping fluid, such as an electric double diaphragm (EODD) pump. The diaphragm assembly prevents the formation of cracks on the diaphragm surface and further prevents the diaphragm from flipping over under negative pressure conditions (e.g., during an intake stroke). The diaphragm assembly also maintains a uniform pumping pressure throughout the operation of the pump and increases the efficiency of the pump.

The diaphragm assembly includes: a piston plate configured to face a piston rod disposed toward an air chamber of the pump; a diaphragm plate configured to face a pumping chamber of a pump and having a protruding surface disposed at a periphery thereof; and a diaphragm configured to be operatively connected with the mounting portion of the pump. The diaphragm is disposed between the diaphragm plate and the piston plate and includes a curved portion that protrudes away from the diaphragm plate. The curved 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 curved portion of the diaphragm has a concave profile, which may also be referred to as an arcuate profile, a C-shaped profile, and a U-shaped profile based on the concavity of the curved portion. The diaphragm also includes a raised sealing portion for clamping within the mounting portion of the pump. Further, the protruding surface of the diaphragm plate extends toward the curved portion of the diaphragm. The diaphragm plate and the piston plate are made of aluminum, cast iron, ductile iron, steel, stainless steel, duplex steel, monel, nickel alloy, plastic, or elastomer. The diaphragm is made of a composite elastomer including rubber, santoprene, plastic, and nylon fabric.

According to an embodiment of the present invention, the diaphragm plate, the diaphragm, and the piston plate are fastened to each other using fasteners passing through a plurality of screw grooves existing around the holes of the diaphragm plate and the piston plate.

According to an embodiment of the invention, one or more of the diaphragm plate and the piston plate comprises a thread on its central hole for locking with a thread present around the piston rod. Furthermore, the stepped portion of the piston rod abuts against the piston plate. The piston rod is part of a linear reciprocating mechanism and imparts reciprocating motion to the diaphragm assembly.

According to an embodiment of the present invention, when the stepped portion of the piston rod abuts against the diaphragm plate, the diameter of the center hole of the diaphragm plate is smaller than or equal to the diameter of the center hole of the piston plate.

According to an embodiment of the present invention, the unsupported length (L1) of the lateral end of the diaphragm assembly is towards the pumping chamber of the pump and is located between the proximal end of the mounting portion and the protruding surface. Further, the unsupported length (L2) of the side end of the diaphragm assembly is toward the piston rod of the pump and is located between the distal end of the mounting portion and the edge of the piston plate. In one embodiment, the unsupported length (L1) may be in a range of 2.5% to 35% of the diameter of the septum (114), and the unsupported length (L2) may be in a range of 2.5% to 35% of the diameter of the septum (114). In a preferred embodiment, the unsupported length (L1) can be in the range of 2.5% to 7.5% of the diameter of the septum (114), and the unsupported length (L2) can be in the range of 5% to 15% of the diameter of the septum (114). The unsupported length (L1) is less than the unsupported length (L2).

According to an embodiment of the invention, the ratio of the diameter of the diaphragm assembly to the stroke length ranges up to from 4: 1 to 12: 1. In a preferred embodiment, the ratio of the diameter of the diaphragm assembly to the stroke length ranges up to from 8: 1 to 12: 1.

According to embodiments of the present invention, the diaphragm may be made of a composite elastomer, such as rubber and nylon fabric. The membrane may be covered with a protective layer at least towards the pumping chamber to prevent damage caused by the chemicals pumped by the pump. The protective layer may be made of a chemically resistant material such as plastic.

Drawings

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.

FIG. 1 illustrates an exemplary cross-sectional view of a diaphragm assembly of a pump according to an embodiment of the present invention.

FIG. 2A illustrates an exemplary representation of the front and back surfaces of a diaphragm plate of a diaphragm assembly according to an embodiment of the invention.

Figure 2B illustrates an exemplary representation of the front and back surfaces of a piston plate of a diaphragm assembly according to an embodiment of the invention.

Fig. 2C shows an exemplary representation of a piston rod of a pump according to an embodiment of the invention.

Fig. 3 shows a profile of a stepped portion of a piston plate according to another embodiment of the invention.

Fig. 4A to 4C show exemplary representations of diaphragm plates and piston plates having various shapes according to different embodiments of the present invention.

Fig. 5 illustrates an exemplary cross-sectional view of a diaphragm assembly installed in an electric double diaphragm pump according to an embodiment of the present invention.

Detailed Description

As used in the specification herein and in the claims that follow, the meaning of "a", "an" and "the" includes plural references unless the context clearly dictates otherwise. Further, as used in the description herein, the meaning of "in …" includes "in …" and "on …" unless the context clearly dictates otherwise.

Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which example 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 skilled 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).

The present invention relates to a diaphragm assembly for a pump. The diaphragm assembly is designed to avoid reverse upset, is prone to cracking, and thus has an extended service life. The use of such a diaphragm assembly improves the efficiency of the pump by maintaining a uniform pumping pressure during operation of the pump.

Fig. 1 shows a cross-sectional view of a diaphragm assembly (100) installed in a (fluid) pump according to an embodiment of the invention. The diaphragm assembly (100) may be installed in a pump for pumping a specific fluid, such as water, oil, and chemicals. Fluid may be drawn into and pumped out of a pumping chamber (102) of the pump. During an intake stroke of the diaphragm assembly (100), a predetermined volume of fluid may be drawn into the pumping chamber (102). The intake stroke of the diaphragm assembly (100) may refer to a condition in which the pressure in the pumping chamber (102) is reduced. Subsequently, during a discharge stroke of the diaphragm assembly (100), fluid may be pumped out of the pumping chamber (102) to an outlet of the pump. The discharge stroke of the diaphragm assembly (100) may refer to a condition of increased pressure in the pumping chamber (102).

On one side, the diaphragm assembly (100) may be connected with a piston rod (104) facing an air chamber of the pump. The piston rod (104) may be operably connected to a linear reciprocating mechanism (as best shown in fig. 4 and described in subsequent paragraphs). The piston rod (104) may transmit the reciprocating motion of the linear reciprocating mechanism to the diaphragm assembly (100) to effect the intake and exhaust strokes of the diaphragm assembly (100).

According to embodiments of the invention, the diaphragm assembly (100) may include a diaphragm plate (106), also shown in FIG. 2A. Specifically, fig. 2A shows an exemplary representation of the front and back surfaces of the diaphragm plate (106). The diaphragm plate (106) may face the pumping chamber (102). The diaphragm plate (106) has a protruding surface (106a) provided at the periphery thereof. It must be understood that the projecting surface (106a) extends in a continuous manner to the entire periphery of the diaphragm plate (106). The diaphragm plate (106) may include a central hole (108a) on a rear surface thereof and a plurality of thread grooves (110a) arranged around the central hole (108 a). In one embodiment, a plurality of thread grooves (110a) may surround the central hole (108 a).

The diaphragm assembly (100) may also include a piston plate (112), also shown in fig. 2B. Specifically, fig. 2B shows an exemplary representation of the front and rear surfaces of the piston plate (112). The piston plate (112) may face a piston rod (104) disposed toward an air chamber of the pump. Further, the piston plate (112) may have a central threaded bore (108b) and a plurality of threaded grooves (110b) arranged around the central bore (108 b). In one embodiment, a plurality of thread grooves (110b) may surround the central hole (108 b). The plurality of threaded grooves (110b) present on the piston plate (112) may have similar dimensions to the plurality of threaded grooves (110a) present on the diaphragm plate (106). Preferably, the diameter of the piston plate (112) may be smaller than the diameter of the diaphragm plate (106).

The diaphragm assembly (100) may include a diaphragm (114) disposed between a diaphragm plate (106) and a piston plate (112). Referring again to fig. 2A, a serrated portion (202) may be provided on the 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 fluid from entering between the diaphragm plate (106) and the diaphragm (114). Additionally, a plurality of raised seals may also be provided at the rear surface of the diaphragm plate (106) in order to prevent fluid from entering between the diaphragm plate (106) and the diaphragm (114). The membrane (114) may be covered with a protective layer at least towards the pumping chamber (102) to prevent damage caused by the chemicals pumped by the pump.

The diaphragm (114) may include a central bore and a plurality of threaded grooves disposed about the central bore. In one embodiment, a plurality of threaded grooves present on the diaphragm (114) may surround the central aperture of the diaphragm (114). Further, the plurality of thread grooves present on the diaphragm (114) may have similar dimensions to the plurality of thread grooves (110a) present on the diaphragm plate (106) and the plurality of thread grooves (110b) present on the piston plate (114). The plurality of thread grooves (110a) present on the diaphragm plate (106), the plurality of thread grooves (110b) present on the piston plate (112), and the plurality of thread grooves present on the diaphragm (114) may be collectively referred to as thread grooves (110) hereinafter.

The diaphragm plate (106), diaphragm (114), and piston plate (112) may be connected to one another using fasteners, such as bolts, screws, and threaded pins. The fastener may pass through the threaded slot (110) to transfer force 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).

The central aperture (108a) present on the diaphragm plate (106), the central aperture present on the diaphragm (114), and the central aperture (108b) present on the piston plate (112) may be collectively referred to hereinafter as the central aperture (108). The central hole (108) may contain an internal thread for locking with a thread present at the edge of the piston rod (104). A piston rod (104) operatively connected to the linear reciprocating mechanism may pass through the central bore (108).

The diaphragm plate (106) and the piston plate (112) may be made of metal, alloy, plastic, or elastomer, depending on the load requirements of the diaphragm assembly (100). Metals and alloys that may be preferably used to fabricate the diaphragm plate (106) and the piston plate (112) may include aluminum, cast iron, ductile iron, steel, stainless steel, duplex steel, monel, and nickel alloys. Preferred plastics for making the diaphragm plate (106) and the piston plate (112) may include, but are not limited to, Polytetrafluoroethylene (PTFE), Polyvinylidene Fluoride (PVDF), and Polyphenylene Ether (PPE). The diaphragm (114) may be made of a composite elastomer including rubber, santoprene, plastic, and nylon fabric, such as rubber and nylon fabric. The protective layer covering the membrane (114) may be made of a chemically resistant material such as plastic.

Referring now to fig. 2C, the piston rod (104) may have a threaded surface (252) that allows the piston rod (104) to be connected to a linear reciprocating mechanism. The piston rod (104) may also have a sliding face (254) for sliding in the sleeve-bushing arrangement by action of the linear reciprocating mechanism. The piston rod (104) may have at least one stepped portion (256) to abut the piston plate (112) of the diaphragm assembly (100). The profile of the stepped portion (256) may vary in different embodiments. For example, a first profile of the stepped portion (256) can be observed in fig. 1. In the first profile, a diameter of a central aperture (108a) present on the diaphragm plate (106) is similar to a diameter of a central aperture (108b) present on the piston plate (112). Further, a stepped portion (256) of the piston rod (104) abuts against a rear surface of the piston plate (112).

An alternative profile, the second profile, of the stepped portion (256) of the piston rod (104) can be seen in fig. 3. In the second profile, a diameter of a central bore (108a) present on the diaphragm plate (106) is smaller than a diameter of a central bore (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 a rear surface of the diaphragm plate (106). This configuration allows force to be transferred from the piston plate (112) to the diaphragm plate (106) and from the diaphragm plate (106) to the piston rod (104).

In an alternative embodiment, the piston rod (104) may have a female threaded portion and either the diaphragm plate (106) or the piston plate (112) may have a male threaded portion. A male threaded portion present on either the diaphragm plate (106) or the piston plate (112) will connect with a female threaded portion of the piston rod (104) to support large axial loads during movement of the diaphragm assembly (100). Such a configuration would allow force to be transferred from the diaphragm plate (106) or the piston plate (112) to the piston rod (104), and vice versa. Further, the piston rod (104) may include a stepped portion to support large axial loads during movement of the diaphragm assembly (100).

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 bore (108) present on the diaphragm plate (106) and the piston plate (112).

The stacked arrangement of the diaphragm plate (106), the piston plate (112), and the diaphragm (114) allows for the prevention of the use of metal inserts in the diaphragm assembly (100). This stacking arrangement also prevents cracks from forming on the surface of any of the diaphragm plate (106), the piston plate (112), and the diaphragm (114), thereby extending the useful life of the diaphragm assembly (100).

Referring back to fig. 1, the diaphragm (114) may include a raised sealing portion (114b) at the edge to allow the diaphragm (114) to be connected/clamped with the mounting portion (116) of the pump. The raised sealing portion (114b) enables a seal between the diaphragm (114) and the mounting portion (116) of the pump to prevent fluid from entering the mounting portion (116). The mounting portion (116) may have a proximal end (116a) and a distal end (116 b). In various embodiments, the raised sealing portion (114b) may have a suitable shape for clamping with the mounting portion (116), such as a bulbous shape, a flat plate shape, and an anchor shape. The mounting portion (116) may have a rounded surface with a large universal radius of contact with the raised sealing portion (114b) of the diaphragm (114). This design of the mounting portion (116) may prevent metal-to-metal sharp contact between the raised sealing portion (114b) and the mounting portion (116), as well as wear of the raised sealing portion (114b), thereby extending the useful life of the diaphragm assembly (100).

The diaphragm (114) includes a curved portion (114a) that protrudes away from the diaphragm plate (106). Although the curved portion (114a) is shown in fig. 1 as having a concave profile, the curved portion (114a) may have other profiles such as a triangular/conical profile, a pyramidal/truncated pyramidal profile, a square profile, and a rectangular profile as suitable embodiments. Based on the concavity of the curved portion, the concave profile may also be referred to as an arcuate profile, a C-shaped profile, and a U-shaped profile. One or both of the diaphragm plate (106) and the piston plate (112) may include a rounded portion with a large universal radius in the area near the curved portion (114a) of the diaphragm (114) to prevent cracking due to sharp metal-to-metal contact.

As shown in fig. 1, the distal end (116b) of the mounting portion (116) of the pump may include a relief notch (118). The relief groove (118) prevents the diaphragm (114) from contacting the rear chamber of the distal end (116b) of the mounting portion (116) during an intake stroke of the diaphragm assembly (100). At high pressure, the diaphragm (114) bulges and can contact the back chamber at the location of the relief groove (118). If significant contact occurs between the diaphragm (114) (made of a soft material) and the rear chamber (made of a hard material), the diaphragm (114) may wear and/or may tear. Thus, the relief groove (118) prevents such wear or tear of the diaphragm (114).

In one embodiment, the protruding surface (106a) of the diaphragm plate (106) may extend towards the curved portion (114a) of the diaphragm (114). This configuration of the curved portion (114a) of the diaphragm (114) and the protruding surface (106a) present at the edge (outside) of the diaphragm plate (106) prevents inversion of the diaphragm assembly (100). In particular, inversion of the diaphragm assembly (100) is prevented by reducing the unsupported length (L1) of the side end of the diaphragm assembly (100) that exists between the proximal end (116a) of the mounting portion (116) and the projecting surface (106a) of the diaphragm plate (106) to approximately 2.5% to 35% of the diameter of the diaphragm (114). Preferably, the unsupported length (L1) is maintained at 2.5% to 7.5% of the diameter of the membrane (114). It should be noted that the unsupported length (L1) exists towards the pumping chamber (102). Another key design factor responsible for avoiding eversion of the diaphragm assembly (100) includes maintaining the unsupported length (L2) of the lateral end of the diaphragm assembly (100) existing between the distal end (116b) of the mounting portion (116) and the edge of the piston plate (112) at about 2.5% to 35% of the diameter of the diaphragm (114). Preferably, the unsupported length (L2) is maintained at 5% to 15% of the diameter of the septum (114). The unsupported length (L1) remains less than the unsupported length (L2) at all times. It should be noted that the large unsupported length (L2) allows for a large stroke of the diaphragm assembly (100). The small unsupported length (L1) prevents the diaphragm (114) from inverting and prevents the material of the diaphragm (114) from entering a severe alternating stress load as compared to the unsupported length (L2). Similarly, the low values of the unsupported lengths (L1 and L2) allow for a small stroke length of the diaphragm assembly (100). For this reason, a small stroke length may result in a significant increase in diaphragm (114) life.

In operation, during an intake stroke of the diaphragm assembly (100), when the diaphragm assembly (100) moves away from the pumping chamber (102), the pressure within the pumping chamber (102) is reduced by the action of the piston rod (104), and a predetermined volume of fluid is drawn into the pumping chamber (102). This intake stroke of the diaphragm assembly (100) creates a negative pressure in the pumping chamber (102), which typically tends to flip/invert the diaphragm assembly (100) in a direction toward the pumping chamber (102). Under such operating conditions, the proposed design factors of the diaphragm assembly (100), including the curved portion (114a) of the diaphragm (114), the protruding surface (106a) of the diaphragm plate (106), and the defined unsupported lengths (L1 and L2), will prevent the diaphragm assembly (100) from inverting in a direction opposite to the pumping chamber (102). The pumping chamber (102) may be of shallow design to draw additional static volume fluid during operation of the pump to achieve maximum dry intake lift.

Additionally or alternatively, the diaphragm assembly (100) may be designed with a large overall diameter and a small stroke length to prevent inversion of the diaphragm assembly (100) under negative pressure conditions. In certain embodiments, the diameter to stroke length ratio of the diaphragm assembly (100) may be maintained at about 4: 1 to 12: 1. Configuring the diaphragm assembly (100) to operate within the above-defined diameter to stroke length ratio will increase the useful life of the diaphragm assembly (100). In a preferred embodiment, the diameter to stroke length ratio of the diaphragm assembly (100) will be in the range of 8: 1 to 12: 1. Implementing such a high diameter to stroke length ratio increases the useful life of the diaphragm assembly (100). In particular, at high operating pressures of the pump, for example at 6 bar, the diaphragm assembly (100) has a service life of more than 1500 hours.

Thereafter, during a discharge stroke of the diaphragm assembly (100), when the diaphragm assembly (100) moves towards the pumping chamber (102), the pressure within the pumping chamber (102) increases by the action of the piston rod (104), and fluid contained in the pumping chamber (102) is pumped via the check valve assembly to the outlet of the pump.

As shown in fig. 4A, the ends of the diaphragm plate (106) and the piston plate (112) may have a cylindrical/linear shape or a conical/beveled shape near the curved portion (114A) of the diaphragm (114). The proximal end (116a) of the mounting structure (116) may also have a cylindrical or conical/arcuate profile. Furthermore, the concavity of the end of the piston plate (112) may vary in different embodiments. In one embodiment, as shown in fig. 4B, the end of the piston plate (112) may have a conical shape. The conical shape of the end of the piston plate (112) provides extended support for the diaphragm (114) under high pressure. In another embodiment, as shown in fig. 4C, the end of the piston plate (112) may have an inverted conical shape. The inverted conical shape of the end of the piston plate (112) reduces the contact area between the piston plate (112) and the diaphragm (114), thereby reducing wear and tear of the diaphragm (114) due to friction with the piston plate (112).

Fig. 5 illustrates an exemplary cross-sectional view of a diaphragm assembly (100) installed in an electric dual diaphragm (EODD) pump (500) according to an embodiment of the invention. Although shown as being installed in an EODD pump by way of example, the diaphragm assembly (100) may be used in any other diaphragm pump, such as an air operated diaphragm pump, a hydraulically operated diaphragm pump, a mechanically operated diaphragm pump, or an electro-mechanically operated diaphragm pump.

Generally, an EODD pump (500) may employ two diaphragm assemblies (100-1, 100-2), each of which forms a component of the diaphragm assembly (100) described above. The diaphragm assembly (100-1, 100-2) may be operatively connected with the linear reciprocating drive (502) via the piston rod assembly (104-1, 104-2) such that during an intake 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 the piston rod (104) described above. Further, the linear reciprocating drive (502) may correspond to a mechanism capable of providing reciprocating motion to the piston rod assemblies (104-1, 104-2). The linear reciprocating drive (502) may be implemented using a suitable mechanism, such as a scotch yoke mechanism, a reciprocating gear drive mechanism, a crank block mechanism, and a reciprocating rotary drive.

In the foregoing detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration the best mode presently contemplated for carrying out the invention. However, this description should not be taken as limiting the scope of the invention in any way. The structure thus conceived is susceptible of numerous modifications and variations, all of which details may be substituted by technically equivalent elements.

Claims

1. A diaphragm assembly (100) for a pump, comprising:

a piston plate (112), the piston plate (112) configured to face a piston rod (104), the piston rod (104) disposed toward an air chamber of the pump;

a diaphragm plate (106), the diaphragm plate (106) being configured to face a pumping chamber (102) of the pump and having a protruding surface (106a) disposed at an edge thereof; and

a diaphragm (114), the diaphragm (114) configured to be operably connected 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 includes a curved portion (114a) that protrudes away from the diaphragm plate (106), and

the protruding surface (106a) of the diaphragm plate (106) extends toward the curved portion (114a) of the diaphragm (114).

2. A diaphragm assembly (100) according to claim 1, wherein the pump is a mechanically operated diaphragm pump.

3. The diaphragm assembly (100) of claim 2, wherein the pump is an electric double diaphragm (EODD) pump.

4. The diaphragm assembly (100) of claim 1, wherein one or more of the diaphragm plate (106) and the piston plate (112) includes threads on a central bore (108a, 108b) thereof for locking with threads present around the piston rod (104).

5. The diaphragm assembly (100) of claim 4, wherein the diaphragm plate (106), the diaphragm (114), and the piston plate (112) are fastened to one another using fasteners that pass through a plurality of threaded grooves (110) surrounding the central bores (108a, 108 b).

6. The diaphragm assembly (100) of claim 1, wherein the stepped portion of the piston rod (104) abuts the piston plate (112).

7. The diaphragm assembly (100) of claim 1, wherein the stepped portion of the piston rod (104) abuts the diaphragm plate (106).

8. The diaphragm assembly (100) of claim 1, wherein the piston rod (104) is part of a linear reciprocating mechanism and imparts a reciprocating motion to the diaphragm assembly (100).

9. The diaphragm assembly (100) of claim 4, wherein a diameter of the central bore (108a) of the diaphragm plate (106) is less than or equal to a diameter of the central bore (108b) of the piston plate (112), and wherein the stepped portion of the piston rod (104) abuts the diaphragm plate (112).

10. Diaphragm assembly (100) according to claim 1, wherein the unsupported length (L1) of the side end of the diaphragm assembly (100) is towards the pumping chamber (102) of the pump and is located between the proximal end (116a) of the mounting portion (116) and the protruding surface (106a), and the unsupported length (L2) of the side end of the diaphragm assembly (100) is towards the piston rod (104) of the pump and is located between the distal end (116b) of the mounting portion (116) and the edge of the piston plate (112).

11. The septum assembly (100) of claim 10, wherein the unsupported length (L1) is in a range of 2.5% to 35% of the diameter of the septum (114) and the unsupported length (L2) is in a range of 2.5% to 35% of the diameter of the septum (114).

12. The septum assembly (100) of claim 10 wherein the unsupported length (L1) is less than the unsupported length (L2).

13. The diaphragm assembly (100) of claim 1, wherein the curved 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. A diaphragm assembly (100) as claimed in claim 1, wherein the diaphragm (114) comprises a raised sealing portion (114b) for clamping within a mounting portion (116) of the pump.

15. The diaphragm assembly (100) of claim 1, wherein the diameter to stroke length ratio of the diaphragm assembly (100) is in the range of 4: 1 to 12: 1, in the above range.

16. The diaphragm assembly (100) of claim 1, wherein the distal end (116b) of the mounting portion (116) of the pump includes a relief groove (118) to prevent the diaphragm (114) from contacting a rear chamber of the distal end (116b) of the mounting portion (116) during an intake stroke of the diaphragm assembly (100).

17. The diaphragm assembly (100) of claim 1, wherein the diaphragm plate (106) and the piston plate (112) are made using a material selected from the group consisting of aluminum, cast iron, ductile iron, steel, stainless steel, duplex steel, monel, nickel alloy, plastic, and elastomer.

18. The diaphragm assembly (100) of claim 1, wherein the diaphragm (114) is made using a composite elastomer comprising rubber, santoprene, plastic, and nylon fabric.

19. The diaphragm assembly (100) of claim 1, wherein an end of the diaphragm plate (106) has one of a cylindrical shape and a conical shape near the curved portion (114a) of the diaphragm (114).

20. The diaphragm assembly (100) of claim 1, wherein the end of the piston plate (112) has one of a cylindrical shape, a conical shape, and an inverted conical shape.

21. The septum assembly (100) of claim 1 wherein the proximal end (116a) of the mounting portion (116) has one of a cylindrical profile and a conical profile.

22. Diaphragm assembly (100) according to claim 1, wherein a protective layer covers the diaphragm (114) at least towards the pumping chamber (102) to prevent damage caused by chemicals pumped by the pump.

23. A diaphragm assembly (100) for a pump, comprising:

wherein the diaphragm (114) is disposed between the diaphragm plate (106) and the piston plate (112) and comprises a curved portion (114a) protruding away from the diaphragm plate (106), and a protruding surface (106a) of the diaphragm plate (106) extends towards the curved portion (114a) of the diaphragm (114),

and wherein an unsupported length (L1) of a side end of the diaphragm assembly (100) is towards the pumping chamber (102) of the pump and is located between the proximal end (116a) of the mounting portion (116) and the protruding surface (106a), and an unsupported length (L2) of a side end of the diaphragm assembly (100) is towards the piston rod (104) of the pump and is located between the distal end (116b) of the mounting portion (116) and an edge of the piston plate (112).