Rotary pump with pressure relief

Claim 2

A rotary pump comprising: a housing having a cylindrical cavity therein; inner and outer rotors with inter-engaging teeth forming pumping chambers mounted for eccentric rotational motion within said cavity; a slidable wall sealing one side of said cavity, said wall being slidable in an axial direction Of said cavity and forming a wall for said pumping chambers when said wall is within a predetermined axial distance of said rotors; resilient biasing means mounted to said housing for resiliently urging said slidable wall into engagement with only one of said rotors, said biasing means permitting said slidable wall to move a distance greater than the predetermined axial distance away from said rotors when said pump generates a pressure greater than a predetermined maximum.

Claim 3

The rotary pump of claim 1 wherein said resilient biasing means is a Belleville spring.

Claim 4

The rotary pump of claim 2 wherein said Belleville spring has one radial slot and at least one hole proximate each side of said slot.

Claim 5

The rotary pump of claim 1 wherein said resilient biasing means is a C-shaped Belleville spring including means permitting gripping of said Belleville spring and tangentially compression thereof.

Claim 6

The rotary pump of claim 1 wherein only the inner rotor is contacted by said slidable wall.

Claim 7

The rotary pump of claim 1 wherein said slidable wall is formed with a substantially centrally located raised boss so as to contact the inner rotor only.

Claim 8

The rotary pump of claim 1 wherein said inner rotor extends to a position beyond said outer rotor so as said slidable wall will contact said inner rotor only.

Claim 9

A rotary pump comprising: a housing having a substantially cylindrical cavity therein; inner and outer rotors having inter-engaging teeth forming the side walls of pumping chambers mounted for eccentric rotation within said cavity; a slidable wall sealing one end of said cavity, said slidable wall additionally forming one wall of said pumping chambers when said slidable wall is within a predetermined distance of said rotors, said slidable wall being formed so as to contact only one of said rotors; and a resilient biasing means mounted in said housing for resiliently urging said slidable wall in a direction towards said rotors, into an engagement with said one of said rotors and to within a predetermined distance of the other of said rotors, said biasing means allowing said slidable wall to move a distance greater than the predetermined distance from said rotors when said pump generates greater than a predetermined maximum pressure.

Claim 10

A rotary pump comprising: a housing having a substantially cylindrical cavity therein; inner and outer rotors having inter-engaging teeth forming the side walls of pumping chambers mounted for eccentric rotation within said cavity; a slidable wall sealing one end of said cavity, said slidable wall additionally forming one wall of said pumping chambers when said slidable wall is within a predetermined distance of said rotors, said slidable wall being formed so as to contact only one of said rotors; and a resilient biasing means mounted in said housing for resiliently urging said slidable wall in a direction towards said rotors, into an engagement with said one of said rotors and to within a predetermined distance of the other of said rotors, said biasing means allowing said slidable wall to move a distance greater than the predetermined distance from said rotors when said pump generates greater than a predetermined maximum pressure.

Claim 11

A rotary pump comprising: a housing having a substantially cylindrical cavity containing eccentrically rotating inner and outer rotors; a wall slidable within and sealing one end of said cavity, said wall interacting with said rotors to form pumping chambers when said wall is located within a predetermined axial distance of one of said rotors and in contact with the other of said rotors: and biasing means mounted to said housing for locating said wall within the predetermined axial distance from said one of said rotors and biasing said wall into engagement with the other of said rotors provided the pump generated pressure does not exceed a predetermined maximum pressure.

Claim 12

A rotary pump comprising: a housing having a substantially cylindrical cavity containing eccentrically rotating inner and outer rotors; a wall slidable within and sealing one end of said cavity, said wall interacting with said rotors to form pumping chambers when said wall is located within a predetermined axial distance of one of said rotors and in contact with the other of said rotors: and biasing means mounted to said housing for locating said wall within the predetermined axial distance from said one of said rotors and biasing said wall into engagement with the other of said rotors provided the pump generated pressure does not exceed a predetermined maximum pressure.

Claim 13

The combination of claim 9 wherein said wall is formed with a centrally raised boss.

Claim 14

The combination of claim 9 wherein the inner rotor is longer than the outer rotor, thereby exposing a larger area of said wall to pump generated pressure.

Claim 15

The combination of claim 9 wherein said biasing means is a C-shaped, self-retaining Belleville spring.