Diaphragm pump

Claim 2

In a diaphragm pump having mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, inlet and outlet passages to the pump chamber, check valves between the pump chamber and both the inlet passage and the outlet passage, and drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber, a diaphragm assembly, comprising: a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; a diaphragm retainer seatable within a recess in an upper pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure unloading; a diaphragm insert washer having an outer cylindrical surface, being seatable within a recess in a lower pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure loading; and, diaphragm deformation restraining means in at least one of said diaphragm, said retainer and said insert washer for restraining radially inward flow of diaphragm material when the upper and lower pump bodies clamp a diaphragm therebetween, thereby compressing and deforming the clamping portion of said diaphragm.

Claim 3

In a diaphragm pump having mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, inlet and outlet passages to the pump chamber, check valves between the pump chamber and both the inlet passage and the outlet passage, and drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber, a diaphragm assembly, comprising: a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; a diaphragm retainer seatable within a recess in an upper pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure unloading; a diaphragm insert washer having an outer cylindrical surface, being seatable within a recess in a lower pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure loading; and, diaphragm deformation restraining means in at least one of said diaphragm, said retainer and said insert washer for restraining radially inward flow of diaphragm material when the upper and lower pump bodies clamp a diaphragm therebetween, thereby compressing and deforming the clamping portion of said diaphragm; wherein the upper pump body defines a lower surface which surrounds its recess and the lower pump body defines an upper surface which surrounds its recess, and wherein at least one of the upper and lower pump bodies defines at least one protruding ridge having a height relative to its surface and substantially surrounding its recess, wherein the at least one ridge bites into and deforms the clamping portion when the bodies are clamped together, and wherein said diaphragm deformation retraining means includes one of said retainer and said insert washer defining a protruding annular rib which, when said retainer and insert washer are seated in their respective recesses and the bodies are clamped together, is concentric with and inside of the at least one protruding ridge and has a height relative to the surface of the one of said retainer and said insert washer in which it sits, the relative height of the annular rib, the relative height of the at least one ridge, and the shape of said diaphragm being such that, upon clamping said diaphragm between the upper and lower pump bodies, the annular rib contacts and bites into said diaphragm before the at least one protruding ridge contacts and bites into said diaphragm.

Claim 4

In a diaphragm pump having mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, inlet and outlet passages to the pump chamber, check valves between the pump chamber and both the inlet passage and the outlet passage, and drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber, a diaphragm assembly, comprising: a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; a diaphragm retainer seatable within a recess in an upper pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure unloading; a diaphragm insert washer having an outer cylindrical surface, being seatable within a recess in a lower pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure loading; and, diaphragm deformation restraining means in at least one of said diaphragm, said retainer and said insert washer for restraining radially inward flow of diaphragm material when the upper and lower pump bodies clamp a diaphragm therebetween, thereby compressing and deforming the clamping portion of said diaphragm; wherein the upper pump body defines a lower surface which surrounds its recess and the lower pump body defines an upper surface which surrounds its recess, and wherein at least one of the upper and lower pump bodies defines at least one protruding ridge having a height relative to its surface and substantially surrounding its recess, wherein the at least one ridge bites into and deforms the clamping portion when the bodies are clamped together, and wherein said diaphragm deformation retraining means includes one of said retainer and said insert washer defining a protruding annular rib which, when said retainer and insert washer are seated in their respective recesses and the bodies are clamped together, is concentric with and inside of the at least one protruding ridge and has a height relative to the surface of the one of said retainer and said insert washer in which it sits, the relative height of the annular rib, the relative height of the at least one ridge, and the shape of said diaphragm being such that, upon clamping said diaphragm between the upper and lower pump bodies, the annular rib contacts and bites into said diaphragm before the at least one protruding ridge contacts and bites into said diaphragm.

Claim 5

The diaphragm assembly of claim 2 wherein the at least one protruding ridge extends upwardly from the lower body and the rib is defined by and extends upwardly from said insert washer and bites into said diaphragm at roughly a junction defined between the webbing portion and the clamping portion.

Claim 6

The diaphragm assembly of claim 3 wherein said diaphragm defines an annular flange extending downwardly from said junction, said flange sized to telescopically surround the upwardly protruding rib of said insert washer.

Claim 7

The diaphragm assembly of claim 4 wherein the lower pump body defines an annular shoulder surrounding and in communication with the recess of the lower body, and wherein said flange is sized to be received within the annular groove defined by the shoulder and the outer cylindrical surface of said insert washer.

Claim 8

The diaphragm assembly of claim 4 wherein, when said insert washer is seated within the recess in the lower body, the rib extends upwardly between 0.013 and 0.015 inches above the ridges in the lower body.

Claim 9

The diaphragm assembly of claim 1 wherein at least one of the upper and lower pump bodies defines at least one protruding ridge substantially surrounding its recess, wherein the at least one ridge bites into and deforms the clamping portion when the bodies are clamped together, and wherein said diaphragm defines an annular flange extending downwardly from a junction defined between the webbing portion and the clamping portion, and wherein said flange is sized to telescopically surround the upper portion of the cylindrical surface of said insert washer.

Claim 10

In a diaphragm pump having mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, inlet and outlet passages to the pump chamber, check valves between the pump chamber and both the inlet passage and the outlet passage, and drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber, a diaphragm assembly, comprising: a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; a diaphragm retainer seatable within a recess in an upper pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure unloading; a diaphragm insert washer having an outer cylindrical surface, being seatable within a recess in a lower pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure loading; and, diaphragm deformation restraining means in at least one of said diaphragm, said retainer and said insert washer for restraining radially inward flow of diaphragm material when the upper and lower pump bodies clamp a diaphragm therebetween, thereby compressing and deforming the clamping portion of said diaphragm; wherein at least one of the upper and lower pump bodies defines at least one protruding ridge substantially surrounding its recess, wherein the at least one ridge bites into and deforms the clamping portion when the bodies are clamped together, and wherein said diaphragm defines an annular flange extending downwardly from a junction defined between the webbing portion and the clamping portion, and wherein said flange is sized to telescopically surround the upper portion of the cylindrical surface of said insert washer; and wherein the lower body defines an annular shoulder surrounding and in communication with the recess of the lower body, and wherein said flange is sized to be firmly received within an annular groove defined by the shoulder and the outer cylindrical surface of said insert washer.

Claim 11

In a diaphragm pump having mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, inlet and outlet passages to the pump chamber, check valves between the pump chamber and both the inlet passage and the outlet passage, and drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber, a diaphragm assembly, comprising: a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; a diaphragm retainer seatable within a recess in an upper pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure unloading; a diaphragm insert washer having an outer cylindrical surface, being seatable within a recess in a lower pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure loading; and, diaphragm deformation restraining means in at least one of said diaphragm, said retainer and said insert washer for restraining radially inward flow of diaphragm material when the upper and lower pump bodies clamp a diaphragm therebetween, thereby compressing and deforming the clamping portion of said diaphragm; wherein at least one of the upper and lower pump bodies defines at least one protruding ridge substantially surrounding its recess, wherein the at least one ridge bites into and deforms the clamping portion when the bodies are clamped together, and wherein said diaphragm defines an annular flange extending downwardly from a junction defined between the webbing portion and the clamping portion, and wherein said flange is sized to telescopically surround the upper portion of the cylindrical surface of said insert washer; and wherein the lower body defines an annular shoulder surrounding and in communication with the recess of the lower body, and wherein said flange is sized to be firmly received within an annular groove defined by the shoulder and the outer cylindrical surface of said insert washer.

Claim 12

The diaphragm assembly of claim 1 wherein said restraining means includes a single unique annular rib extending up from said insert washer or down from said retainer and operable to bite into said diaphragm upon clamping the upper and lower pump bodies together.

Claim 13

A diaphragm pump, comprising: mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, at least one of said bodies defining at least one protruding ridge substantially surrounding its chamber; inlet and outlet passages to the pump chamber; a check valve between each passage and the pump chamber; drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber; a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; wherein the at least one protruding ridge is adapted to bite into, deform and hold the clamping portion when the bodies are clamped together; and a protruding annular rib fixed relative to one of said upper and lower bodies, said rib positioned interiorly of said at least one ridge, and wherein the upper pump body defines a lower surface and the lower pump body defines an upper surface, and wherein said at least one protruding ridge has a height relative to the surface of the one of said upper and lower bodies and said protruding annular rib has a height relative to the surface of the one of said upper and lower bodies, the relative height of the annular rib, the relative height of the at least one ridge, and the shape of said diaphragm being such that, upon clamping said diaphragm between the upper and lower pump bodies, the annular rib contacts and bites into said diaphragm before the at least one protruding ridge contacts and bites into said diaphragm.

Claim 14

A diaphragm pump, comprising: mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, at least one of said bodies defining at least one protruding ridge substantially surrounding its chamber; inlet and outlet passages to the pump chamber; a check valve between each passage and the pump chamber; drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber; a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; wherein the at least one protruding ridge is adapted to bite into, deform and hold the clamping portion when the bodies are clamped together; and a protruding annular rib fixed relative to one of said upper and lower bodies, said rib positioned interiorly of said at least one ridge, and wherein the upper pump body defines a lower surface and the lower pump body defines an upper surface, and wherein said at least one protruding ridge has a height relative to the surface of the one of said upper and lower bodies and said protruding annular rib has a height relative to the surface of the one of said upper and lower bodies, the relative height of the annular rib, the relative height of the at least one ridge, and the shape of said diaphragm being such that, upon clamping said diaphragm between the upper and lower pump bodies, the annular rib contacts and bites into said diaphragm before the at least one protruding ridge contacts and bites into said diaphragm.

Claim 15

The diaphragm pump of claim 10 wherein said at least one ridge extends upwardly from said lower body.

Claim 16

A diaphragm pump, comprising: mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, at least one of said bodies defining at least one protruding ridge substantially surrounding its chamber; inlet and outlet passages to the pump chamber; a check valve between each passage and the pump chamber; drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber; a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; wherein the at least one protruding ridge is adapted to bite into, deform and hold the clamping portion when the bodies are clamped together; a protruding annular rib fixed relative to one of said upper and lower bodies, said rib positioned interiorly of said at least one protruding ridge and sized to bite into said diaphragm before said at least one ridge; wherein said ridge extends upwardly from said lower body; and a diaphragm insert washer having an outer cylindrical surface and seated within a recess in said lower body and wherein said rib is integral with and extends upwardly from said insert washer; wherein the upper pump body defines a lower surface and the lower pump body defines an upper surface which surrounds its recess, and wherein said at least one protruding ridge has a height relative to the upper surface and said protruding annular rib has a height relative to the surface of the one of said upper and lower bodies, the relative height of the annular rib, the relative height of the at least one ridge, and the shape of said diaphragm being such that, upon clamping said diaphragm between the upper and lower pump bodies, the annular rib contacts and bites into said diaphragm before the at least one protruding ridge contacts and bites into said diaphragm.

Claim 17

A diaphragm pump, comprising: mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, at least one of said bodies defining at least one protruding ridge substantially surrounding its chamber; inlet and outlet passages to the pump chamber; a check valve between each passage and the pump chamber; drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber; a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; wherein the at least one protruding ridge is adapted to bite into, deform and hold the clamping portion when the bodies are clamped together; a protruding annular rib fixed relative to one of said upper and lower bodies, said rib positioned interiorly of said at least one protruding ridge and sized to bite into said diaphragm before said at least one ridge; wherein said ridge extends upwardly from said lower body; and a diaphragm insert washer having an outer cylindrical surface and seated within a recess in said lower body and wherein said rib is integral with and extends upwardly from said insert washer; wherein the upper pump body defines a lower surface and the lower pump body defines an upper surface which surrounds its recess, and wherein said at least one protruding ridge has a height relative to the upper surface and said protruding annular rib has a height relative to the surface of the one of said upper and lower bodies, the relative height of the annular rib, the relative height of the at least one ridge, and the shape of said diaphragm being such that, upon clamping said diaphragm between the upper and lower pump bodies, the annular rib contacts and bites into said diaphragm before the at least one protruding ridge contacts and bites into said diaphragm.

Claim 18

The diaphragm pump of claim 12 wherein said diaphragm defines an annular flange extending downwardly from the junction defined between the webbing portion and the clamping portion and sized to telescopically surround the upper portion of said upwardly protruding rib.

Claim 19

The diaphragm pump of claim 13 wherein said lower pump body defines an annular shoulder surrounding and in communication with the recess of the lower body and inside of said at least one ridge, and wherein said flange is adapted to be received within an annular groove defined by the shoulder and the outer cylindrical surface of said insert washer.

Claim 20

The diaphragm pump of claim 13 wherein said rib is adapted to bite into said diaphragm at the junction and just inside of the flange.

Claim 21

The diaphragm pump of claim 14 wherein, when said insert washer is seated within the recess in the lower body, said rib extends upwardly between 0.013 and 0.015 inches above said at least one ridge in the lower body.

Claim 22

The diaphragm pump of claim 11 further including a diaphragm retainer seated within a recess in said upper body and adapted to receive said diaphragm in a complementary shaped recess during pressure unloading, said retainer adapted to form a backup for said diaphragm as said rib bites into said diaphragm when said bodies are clamped together.

Claim 23

The diaphragm pump of claim 12 wherein said lower body defines at least two upwardly extending ridges substantially surrounding its chamber and said upper body defines at least two ridges substantially surrounding its chamber, said at least two ridges of both said upper and lower bodies cooperating to clamp said diaphragm at its clamping portion when said bodies are clamped together.

Claim 24

The diaphragm pump of claim 12 wherein said diaphragm includes downwardly extending centering means for engaging with said rib and centering said diaphragm over said insert washer and pump chamber.

Claim 25

A diaphragm pump, comprising: mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, the upper and lower pump bodies defining lower and upper surfaces, respectively, which mutually engage and surround the driving fluid chamber when said bodies are clamped together, and at least one of said bodies defining at least one protruding ridge substantially surrounding its chamber; inlet and outlet passages to the pump chamber; a check valve between each passage and the pump chamber; drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber; a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; wherein the at least one protruding ridge is adapted to bite into, deform and hold the clamping portion when the bodies are clamped together; and, centering means in said diaphragm and said lower pump body for substantially precisely locating said diaphragm in coaxial alignment with said lower pump body, said centering means including a flange extending downwardly from said diaphragm and engaging with a flange engaging surface of said lower body which extends upwardly of the top surface of the lower body.

Claim 26

A diaphragm pump, comprising: mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, the upper and lower pump bodies defining lower and upper surfaces, respectively, which mutually engage and surround the driving fluid chamber when said bodies are clamped together, and at least one of said bodies defining at least one protruding ridge substantially surrounding its chamber; inlet and outlet passages to the pump chamber; a check valve between each passage and the pump chamber; drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber; a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; wherein the at least one protruding ridge is adapted to bite into, deform and hold the clamping portion when the bodies are clamped together; and, centering means in said diaphragm and said lower pump body for substantially precisely locating said diaphragm in coaxial alignment with said lower pump body, said centering means including a flange extending downwardly from said diaphragm and engaging with a flange engaging surface of said lower body which extends upwardly of the top surface of the lower body.

Claim 27

The diaphragm pump of claim 20 wherein the flange is cylindrical and wherein said lower body includes a diaphragm insert washer defining a generally cylindrical flange engaging surface.

Claim 28

In a diaphragm pump having mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, inlet and outlet passages to the pump chamber, check valves between the pump chamber and both the inlet passage and the outlet passage, and drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber, a diaphragm assembly, comprising: a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; a diaphragm retainer seatable within a recess in an upper pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure unloading; a diaphragm insert washer having an outer cylindrical surface, being seatable within a recess in a lower pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure loading; and, wherein the upper pump body defines a lower surface which surrounds its recess and the lower pump body defines an upper surface which surrounds its recess, and wherein at least one of the upper and lower pump bodies defines at least one protruding ridge having a height relative to its surface and substantially surrounding its recess, wherein the at least one ridge bites into and deforms the clamping portion when the bodies are clamped together, and wherein one of said retainer and said insert washer defines a protruding annular rib which, when said retainer and insert washer are seated in their respective recesses and the bodies are clamped together, is concentric with and inside of the at least one protruding ridge and has a height relative to the surface of the one of said retainer and said insert washer in which it sits, the relative height of the annular rib being greater than the relative height of the at least one ridge.

Claim 29

In a diaphragm pump having mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, inlet and outlet passages to the pump chamber, check valves between the pump chamber and both the inlet passage and the outlet passage, and drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber, a diaphragm assembly, comprising: a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; a diaphragm retainer seatable within a recess in an upper pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure unloading; a diaphragm insert washer having an outer cylindrical surface, being seatable within a recess in a lower pump body and adapted to receive said diaphragm in a complementary shaped recess during pressure loading; and, wherein the upper pump body defines a lower surface which surrounds its recess and the lower pump body defines an upper surface which surrounds its recess, and wherein at least one of the upper and lower pump bodies defines at least one protruding ridge having a height relative to its surface and substantially surrounding its recess, wherein the at least one ridge bites into and deforms the clamping portion when the bodies are clamped together, and wherein one of said retainer and said insert washer defines a protruding annular rib which, when said retainer and insert washer are seated in their respective recesses and the bodies are clamped together, is concentric with and inside of the at least one protruding ridge and has a height relative to the surface of the one of said retainer and said insert washer in which it sits, the relative height of the annular rib being greater than the relative height of the at least one ridge.

Claim 30

A diaphragm pump, comprising: mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body; inlet and outlet passages to the pump chamber; check valves between the pump chamber and both the inlet passage and the outlet passage; drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber; a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; and, diaphragm deformation restraining means for restraining radially inward flow of diaphragm material when the upper and lower pump bodies clamp a diaphragm therebetween, thereby compressing and deforming the clamping portion of said diaphragm, said restraining means including a single, uniquely sized annular rib extending up from said lower pump body or down from said upper pump body and operable to bite into said diaphragm upon said upper and lower pump bodies being clamped together.

Claim 31

A diaphragm pump, comprising: mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body; inlet and outlet passages to the pump chamber; check valves between the pump chamber and both the inlet passage and the outlet passage; drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber; a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion; and, diaphragm deformation restraining means for restraining radially inward flow of diaphragm material when the upper and lower pump bodies clamp a diaphragm therebetween, thereby compressing and deforming the clamping portion of said diaphragm, said restraining means including a single, uniquely sized annular rib extending up from said lower pump body or down from said upper pump body and operable to bite into said diaphragm upon said upper and lower pump bodies being clamped together.

Claim 32

A diaphragm pump, comprising: mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, the upper and lower pump bodies defining lower and upper surfaces, respectively, which mutually engage and surround the driving fluid chamber when said bodies are clamped together, and at least one of said bodies defining at least one protruding ridge substantially surrounding its chamber; inlet and outlet passages to the pump chamber; a check valve between each passage and the pump chamber; drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber; a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion, said diaphragm defining a junction at the intersection of the webbing portion and the clamping portion; wherein the at least one protruding ridge is adapted to bite into, deform and hold the clamping portion when the bodies are clamped together; and, centering means in said diaphragm and said lower pump body for substantially precisely locating said diaphragm in coaxial alignment with said lower pump body, said centering means including an annular flange extending downwardly from the junction of said diaphragm.

Claim 33

A diaphragm pump, comprising: mating upper and lower pump bodies adapted to clamp a diaphragm therebetween which separates a driving fluid chamber in the upper body from a pump chamber in the lower body, the upper and lower pump bodies defining lower and upper surfaces, respectively, which mutually engage and surround the driving fluid chamber when said bodies are clamped together, and at least one of said bodies defining at least one protruding ridge substantially surrounding its chamber; inlet and outlet passages to the pump chamber; a check valve between each passage and the pump chamber; drive means for alternately pressure loading and unloading driving fluid in the driving fluid chamber; a diaphragm having a central body portion and an annular clamping portion connected to the body portion by an annular webbing portion, said diaphragm defining a junction at the intersection of the webbing portion and the clamping portion; wherein the at least one protruding ridge is adapted to bite into, deform and hold the clamping portion when the bodies are clamped together; and, centering means in said diaphragm and said lower pump body for substantially precisely locating said diaphragm in coaxial alignment with said lower pump body, said centering means including an annular flange extending downwardly from the junction of said diaphragm.