ENHANCING EFFICIENCY IN A PRESSURE EXCHANGER

1 . A pressure exchanger comprising:

a rotor configured to rotate to exchange pressure between a first fluid at a first pressure and a second fluid at a second pressure, wherein the rotor forms ducts that are routed from a first distal end of the rotor to a second distal end of the rotor;

a first end cover disposed at the first distal end of the rotor, wherein the first end cover forms a high pressure in (HPIN) port configured to provide the first fluid at the first pressure into the ducts, and wherein the first end cover forms a low pressure out (LPOUT) port configured to receive the first fluid from the ducts at a third pressure that is lower than the first pressure, wherein one or more sidewalls of the first end cover that form the HPIN port or the LPOUT port are substantially planar; and

a second end cover disposed at the second distal end of the rotor, wherein the second end cover forms a low pressure in (LPIN) port configured to provide the second fluid at the second pressure into the ducts and forms a high pressure out (HPOUT) port configured to receive the second fluid from the ducts at a fourth pressure that is higher than the second pressure.

2 . The pressure exchanger of claim 1 , wherein the one or more sidewalls of the first end cover that form the HPIN port have a substantially straight edge that substantially matches a corresponding substantially straight edge of a duct formed by the rotor.

3 . The pressure exchanger of claim 1 , wherein:

the first end cover comprises first substantially planar radial sidewalls, a first inner sidewall, and a first outer sidewall that form the HPIN port, the first substantially planar radial sidewalls being disposed between a first center of the first end cover and a first perimeter of the first end cover, the first inner sidewall being proximate the first center of the first end cover, and the first outer sidewall being proximate the first perimeter of the first end cover; and

the second end cover comprises second substantially planar radial sidewalls, a second inner sidewall, and a second outer sidewall that form the HPOUT port, the second substantially planar radial sidewalls being disposed between a second center of the second end cover and a second perimeter of the second end cover, the second inner sidewall being proximate the second center of the second end cover, and the second outer sidewall being proximate the second perimeter of the second end cover.

4 . The pressure exchanger of claim 1 , wherein the rotor forms the ducts in a plurality of concentric rows, and wherein a ratio of a number of the concentric rows to inches of diameter of the rotor is about 0.3 to about 0.45.

5 . The pressure exchanger of claim 1 , wherein the rotor forms the ducts in at least three concentric rows.

6 . The pressure exchanger of claim 1 further comprising:

a first interconnect configured to provide the first fluid to the HPIN port of the first end cover;

a first spacer disposed in the first end cover between the first interconnect and the LPIN port;

a second interconnect configured to receive the first fluid from the LPOUT port of the first end cover; and

a second spacer disposed in the first end cover between the LPOUT port and the second interconnect.

7 . The pressure exchanger of claim 6 , wherein at least one of the first spacer or the second spacer is a thermoplastic material.

8 . The pressure exchanger of claim 6 , wherein at least one of the first spacer or the second spacer is polyvinyl chloride (PVC).

9 . The pressure exchanger of claim 1 , wherein angular spacing between the HPIN port and the LPOUT port of the first end cover substantially matches corresponding angular spacing between a first leading radial sidewall of a first duct of the rotor and a second leading radial sidewall of a second duct that is adjacent to the first duct.

10 . The pressure exchanger of claim 1 , wherein angular spacing between the LPIN port and the HPOUT port of the first end cover substantially matches corresponding angular spacing between a first leading radial sidewall of a first duct of the rotor and a second leading radial sidewall of a second duct that is adjacent to the first duct.

11 . The pressure exchanger of claim 1 , wherein:

a ratio of diametral clearance to axial clearance is about 1 to about 3.5;

the diametral clearance is between the rotor and a sleeve or between the rotor and a center post; and

the axial clearance being a height difference between the sleeve and the rotor or between the center post and the rotor.

12 . The pressure exchanger of claim 1 , wherein:

leading radial sidewalls and trailing radial sidewalls of the LPOUT port and the HPOUT port are not axial;

the leading radial sidewalls and the trailing radial sidewalls of the LPOUT port and the HPOUT port are inclined at an angle that is substantially proportional to rotor revolutions per minute; and

the angle is about 30 degrees to about 70 degrees.

13 . The pressure exchanger of claim 1 further comprising a spacer that has a lofted shape that transitions from a round shape of an interconnect to a non-round shape of a corresponding port of the first end cover.

14 . A pressure exchanger comprising:

a rotor configured to rotate to exchange pressure between a first fluid at a first pressure and a second fluid at a second pressure, wherein the rotor forms ducts that are routed from a first distal end of the rotor to a second distal end of the rotor; and

a first end cover forming a first port and a second port, wherein a first substantially straight radial edge of the first port and a second substantially straight radial edge of the second port substantially match corresponding substantially straight edges of the ducts of the rotor.

15 . The pressure exchanger of claim 14 further comprising a second end cover forming a third port and a fourth port, wherein a third substantially straight radial edge of the third port and a fourth substantially straight radial edge of the fourth port substantially match the corresponding substantially straight edges of the ducts of the rotor.

16 . The pressure exchanger of claim 14 , wherein the rotor forms the ducts in a plurality of concentric rows, and wherein a ratio of a number of the concentric rows to inches of diameter of the rotor is about 0.3 to about 0.45.

17 . The pressure exchanger of claim 14 , wherein the rotor forms the ducts in at least three concentric rows.

18 . A pressure exchanger comprises:

a rotor configured to rotate to exchange pressure between a first fluid at a first pressure and a second fluid at a second pressure, wherein the rotor forms ducts that are routed from a first distal end of the rotor to a second distal end of the rotor;

a first end cover disposed at the first distal end of the rotor, the first end cover forming a first port and a second port;

a first interconnect configured to provide the first fluid to the first port of the first end cover; and

a first spacer disposed in the first end cover between the first interconnect and the first port.

19 . The pressure exchanger of claim 18 further comprising:

a second end cover disposed at the second distal end of the rotor, the second end cover forming a third port and a fourth port;

a second interconnect configured to provide the second fluid to the third port of the second end cover; and

a second spacer disposed in the second end cover between the second interconnect and the third port.

20 . The pressure exchanger of claim 19 , wherein at least one of the first spacer or the second spacer is a thermoplastic material.