Fluid pump

A liquid pump, the liquid pump comprising,

• a pump housing defining a first cylinder having a first cylinder proximal portion, a first cylinder distal portion, and a first cylinder central axis, and a second cylinder having a second cylinder proximal portion, a second cylinder distal portion, and a second cylinder central axis;
• a rotating actuator disposed in the pump housing, the rotating actuator having a peripheral surface and having an annular groove defined in the peripheral surface, wherein the annular groove defines a first cam surface and a second cam surface;
• a first piston disposed in the first cylinder and a second piston disposed in the second cylinder, wherein the first piston has a first proximal piston end, a first distal piston end, and a first piston central axis aligned coaxially with the first cylinder central axis, and the first piston has a first piston cam follower at the first proximal piston end, the first piston cam follower extending out of the first cylinder into the annular groove, and wherein the second piston has a second proximal piston end, a second distal piston end, and a second piston central axis aligned coaxially with the second cylinder central axis, and the second piston has a second piston cam follower at a second piston proximal end, the second piston cam follower extending out of the second piston into the annular groove;
• the pump housing having an inlet port in an inlet fluid communication with the first cylinder at the first cylinder proximal portion and the second cylinder at a second proximal cylinder portion, the inlet fluid communication defining an inlet flow path to the first cylinder and the second cylinder;
• the pump housing having an outlet port in outlet fluid communication with the first cylinder at the first cylinder proximal portion and the second cylinder at the second proximal cylinder portion, the outlet fluid communication defining an outlet flow path from the first cylinder and the second cylinder;
• a first inlet check valve disposed in the first cylinder at the first cylinder distal portion and a second inlet check valve disposed in the second cylinder at the second cylinder distal portion, the first inlet check valve and the second inlet check valve each being an umbrella valve having an inlet valve closed state and an inlet valve open state;
• and
• a first outlet check valve disposed intermediate the first cylinder distal portion and the outlet port and a second outlet check valve disposed intermediate a second distal cylinder portion and the outlet port, the first outlet check valve and the second outlet check valve each having an outlet valve closed state and an outlet valve open state and wherein the first outlet check valve and the second outlet check valve are spring-biased toward the outlet valve closed state.

A liquid pump, the liquid pump comprising,

• a pump housing defining a plurality of cylinders, including a first cylinder and a second cylinder, each of the plurality of cylinders having a proximal cylinder portion and a distal cylinder portion and a cylinder central axis;
• a rotating actuator disposed in the pump housing, the rotating actuator having a peripheral surface and having an annular groove defined in the peripheral surface, wherein the annular groove defines a first cam surface and a second cam surface;
• a plurality of pistons, including a first piston and a second piston, disposed in the plurality of cylinders, wherein the first piston has a first proximal piston end, a first distal piston end, and a first piston central axis aligned coaxially with the cylinder central axis, and the first piston has a first piston cam follower at the first proximal piston end, the first piston cam follower extending out of the first cylinder into the annular groove, and wherein the second piston has a second proximal piston end, a second distal piston end, and a second piston central axis aligned coaxially with a second cylinder central axis, and the second piston has a second piston cam follower at a second piston proximal end, the second piston cam follower extending out of the second piston into the annular groove;
• an inlet port in inlet fluid communication with each of the plurality of cylinders at the proximal cylinder portion, the inlet fluid communication defining an inlet flow path;
• an outlet port in outlet fluid communication with each of the plurality of cylinders at the proximal cylinder portion, the outlet fluid communication defining an outlet flow path;
• a first inlet check valve disposed in the first cylinder at a first distal cylinder portion and a second inlet check valve disposed in the second cylinder at a second distal portion, the first inlet check valve and the second inlet check valve each having an inlet valve closed state and an inlet valve open state;
• a first outlet check valve disposed intermediate the first distal cylinder portion and the outlet port and a second outlet check valve disposed intermediate a second distal cylinder portion and the outlet port, the first outlet check valve and the second outlet check valve each having an outlet valve closed state and an outlet valve open state;
• and
• the outlet port being in fluid communication with the inlet port via a pressure control member, the pressure control member comprising an overpressure relief check valve spring biased to prevent a fluid flow from the outlet port to the inlet port at a first outlet port fluid pressure and to allow the fluid flow from the outlet port to the inlet port at a second outlet port fluid pressure, the second outlet port fluid pressure being higher than the first outlet port fluid pressure.