Pump with a resilient seal
A pump comprises a housing, with an interior defining a rotor path, an inlet formed in the housing at a first position on said rotor path, an outlet formed in the housing at a second position on said rotor path spaced from said first position. A rotor is rotatable in the housing with a first surface that seals against the housing. A second surface is formed on said rotor circumferentially spaced from said first surface and forms a chamber that travels around said rotor path to convey fluid from the inlet to the outlet. A resilient seal formed with the housing is located on the rotor path to prevent fluid flow from said outlet to said inlet past the seal. A passage may be provided to supply fluid to an under surface of the seal at a pressure that acts to urge the seal against the rotor.
1. A pump comprising:
a housing having an interior defining a rotor path, and comprising a resilient seal, wherein the resilient seal and a remainder of the housing are formed in one piece and comprise a same material;
an inlet formed in the housing at a first position on said rotor path;
an outlet formed in the housing at a second position on said rotor path spaced from said first position;
a rotor rotatable in said housing,
at least one first surface formed on the rotor and sealing against said rotor path of the housing,
at least one second surface formed on said rotor circumferentially spaced from said at least one first surface and forming a chamber with the rotor path that travels around said rotor path on rotation of the rotor to convey fluid around the housing from the inlet to the outlet;
wherein the resilient seal is located on said rotor path and extending between the outlet and the inlet in a direction of rotation of said rotor;
wherein the at least one first surface seals with, and resiliently deforms, the resilient seal, as the rotor rotates around the rotor path within the housing to prevent the fluid flow from said outlet to said inlet past the resilient seal; and
wherein the resilient seal is thinner than the remainder of the housing.
2. A pump according to claim 1 , wherein the housing and the resilient seal are formed from a plastics material by a single injection molding process.
3. A pump according to claim 1 , wherein the resilient seal is formed by a flexible plastics wall.
4. A pump according to claim 3 , wherein the flexible plastics wall has a thickness of between 0.1 mm and 0.3 mm.
5. A pump according to claim 4 , wherein the thickness of the flexible plastics wall is 0.15 mm.
6. A pump according to claim 4 , wherein the flexible plastics wall is formed by an injection molding process using a hydraulic ram during an injection cycle to set the flexible plastics wall thickness of the resilient seal.
7. The pump according to claim 1 , wherein the resilient seal is more flexible than the remainder of the housing.
8. The pump according to claim 1 , wherein the rotor comprises at least two first surfaces formed on the rotor and sealed against said rotor path of the housing, each of the at least two first rotor surfaces sealing with and resiliently deforming the resilient seal as the rotor rotates around the rotor path within the housing, to prevent the fluid flow from said outlet to said inlet past the resilient seal.
9. The pump according to claim 1 , wherein the interior of the housing defines a housing inner surface that defines the rotor path; the first and second positions being on the housing inner surface; the rotor including the at least one second surface recessed in the at least one first surface, the at least one second surface of the rotor forming the chamber with the housing inner surface; the at least one first surface of the rotor forming a fluid-tight seal around the at least one second surface.
10. The pump according to claim 9 , wherein the housing inner surface defines a cylindrical rotor path and the at least one first surface of the rotor forms the fluid-tight seal with the cylindrical rotor path of the housing inner surface.