Pumps
A pump is formed by a housing ( 10 ) having an inlet ( 11 ) and an outlet ( 12 ) for a fluid. The housing ( 10 ) contains a rotator ( 13 ) provided with at least one surface recess ( 17 a, 17 b, 17 c, 17 d ) that forms with an interior surface of the rotor a chamber ( 18 a, 18 b, 18 c, 18 d ) that, on rotation of the rotor ( 13 ), conveys fluid from the inlet ( 11 ) to the outlet ( 12 ). A flexible seal ( 23 ) is provided on or as part of the housing ( 10 ) and is located between the inlet ( 11 ) to the outlet ( 12 ) to engage the rotor ( 13 ) to prevent fluid passing from the outlet ( 12 ) to the inlet ( 11 ). A second inlet ( 16 ) is provided leading to the outlet ( 12 ) for the supply to the outlet ( 12 ) of a second fluid and the second inlet ( 16 ) also supplies the second fluid to the back of the seal ( 23 ) to urge the seal ( 23 ) against the rotor ( 13 ).
1. A pump, said pump comprising:
a housing having an inlet and an outlet for a fluid and containing a rotor provided with at least one surface recess that forms with an interior surface of the rotor a chamber that, on rotation of the rotor, conveys fluid from the inlet to the outlet,
a flexible seal being provided on or as part of the housing and located between the inlet and the outlet to engage the rotor to prevent fluid passing from the outlet to the inlet,
the seal backed by a seal chamber;
a second inlet being provided for the supply of a second fluid to the outlet to mix with fluid in the outlet and also to the seal chamber to apply second fluid to the seal, to urge the seal against the rotor.
2. A pump according to claim 1 wherein the second fluid is supplied to the outlet at a first pressure and is supplied to the seal at a second pressure, the first pressure being less than the second pressure.
3. A pump according to claim 1 wherein the second inlet has a first branch and a second branch, the first branch leading to the chamber and the second branch leading to the outlet.
4. A pump according to claim 3 wherein the second fluid is supplied to the outlet at a first pressure and is supplied to the seal at a second pressure, the first pressure being less than the second pressure; and the second branch includes a regulator for reducing the pressure of the second fluid to said first pressure before passing to the outlet.
5. A pump according to claim 1 wherein the second inlet passes said second fluid into said chamber, the second fluid then exiting said chamber to the outlet.
6. A pump according to claim 5 wherein the second fluid is supplied to the outlet at a first pressure and is supplied to the seal at a second pressure, the first pressure being less than the second pressure; and the second fluid exits the chamber through a chamber outlet, the chamber outlet including a pressure reducing device for reducing the pressure of the second fluid to said first pressure before passing to the outlet.
7. A pump according to claim 6 wherein second inlet and the second outlet include respective non-return valves so that rotation of the rotor to move the seal into and out of the chamber pumps the second fluid from the chamber to the chamber outlet.
8. A pump according to claim 2 wherein the second inlet includes a pressure flow regulator for controlling the pressure of the second fluid to said second pressure.
9. A pump according to claim 1 wherein the second inlet is controlled by a shut-off valve.
10. A pump according to claim 1 wherein a check valve is provided in the outlet upstream of the connection between the second inlet and the outlet to prevent or restrict reverse flow through the outlet.
11. A method of mixing first and second fluids comprising pumping the first fluid from an inlet to an outlet with a pump including a rotor having a flexible seal urged against the rotor, passing the second fluid to urge the seal against the rotor and passing the second fluid to the outlet to mix with the first fluid.
12. A pump according to claim 2 wherein the housing includes a seal chamber surrounding a surface of the seal opposite the surface of the seal engaging the rotor, the second fluid being supplied to said seal chamber to urge the seal against the rotor.
13. A pump according to claim 12 wherein the second inlet has a first branch and a second branch, the first branch leading to the chamber and the second branch leading to the outlet.
14. A pump according to claim 1 wherein the second inlet includes a pressure flow regulator for controlling the pressure of the second fluid to said second pressure.
15. A pump according to claim 2 wherein the second inlet is controlled by a shut-off valve.
16. A pump according to claim 1 wherein the second inlet is controlled by a shut-off valve.
17. A pump according to claim 2 wherein a check valve is provided in the outlet upstream of the connection between the second inlet and the outlet to prevent or restrict reverse flow through the outlet.
18. A pump according to claim 1 wherein a check valve is provided in the outlet upstream of the connection between the second inlet and the outlet to prevent or restrict reverse flow through the outlet.
19. A pump according to claim 9 wherein a check valve is provided in the outlet upstream of the connection between the second inlet and the outlet to prevent or restrict reverse flow through the outlet.