Pistons for use in fluid exchange devices and related devices, systems, and methods

1. A device for exchanging at least one property between fluids, the device comprising:

at least one tank comprising:

a first side for receiving a first fluid with a first property; and

a second side for receiving a second fluid with a second property; and

at least one piston in the at least one tank, the at least one piston being independently disposed entirely within the at least one tank and configured to travel unconstrained within the at least one tank, the at leat one piston configured to move freely within the at least one tank based only on a force applied to the at least one piston by at least one of the first fluid or the second fluid within the at least one tank, the at least one piston configured to separate the first fluid from the second fluid, the at least one piston further configured to substantially prohibit the second fluid from traveling from the second side to the first side, wherein the at least one piston is configured to enable the first fluid to travel from the first side to the second side.

2. The device of claim 1 , wherein the at least one piston comprises a valve, the valve configured to enable the first fluid to travel from the first side to the second side and to substantially prohibit the second fluid from traveling through the valve from the second side to the first side.

3. The device of claim 1 , wherein at least one end of the at least one piston comprises a chamfered edge portion configured to create fluid vortices at an interface between the at least one piston and an inner wall of the at least one tank to minimize particles from entering the interface between the at least one piston and the inner wall of the at least one tank.

4. The device of claim 1 , further comprising at least one sensor configured to detect a presence of the at least one piston.

5. The device of claim 1 , further comprising at least one magnet positioned at locations about a circumference of the at least one piston, the at least one magnet configured to produce a magnetic field for sensing by an associated sensor.

6. The device of claim 1 , wherein the at least one piston is configured to substantially prohibit the second fluid from traveling through the at least one piston from the second side to the first side.

7. The device of claim 1 , wherein the at least one piston comprises an abrasion resistant material configured to be at least partially buoyant in at least one of the first fluid or the second fluid.

8. The device of claim 1 , further comprising a valve device configured to selectively place the first fluid at a first pressure in communication with the second fluid at a second pressure through the at least one piston in order to pressurize the second fluid to a higher pressure.

9. A system for exchanging pressure between fluids, the system comprising:

at least one tank comprising:

a clean side for receiving a clean fluid at a higher pressure; and

a dirty side for receiving a downhole fluid at a lower pressure;

at least one piston disposed in the at least one tank and configured to travel unconstrained within the at least one tank based only on a force applied to the at least one piston by at least one of the clean fluid or the downhole fluid, the at least one piston configured to separate the clean fluid from the downhole fluid, the at least one piston further configured to at least partially prohibit the downhole fluid from traveling from the dirty side to the clean side; and

a valve device configured to selectively place the clean fluid at the higher pressure in communication with the downhole fluid at the lower pressure through the at least one piston in order to pressurize the downhole fluid to a second higher pressure.

10. The system of claim 9 , wherein the at least one piston is configured to substantially prohibit the downhole fluid from traveling through the at least one piston from the dirty side to the clean side.

11. The system of claim 9 , wherein the at least one piston is configured to enable the clean fluid to travel from the clean side to the dirty side.

12. The system of claim 9 , wherein the at least one piston comprises a piston valve positioned within the at least one piston, the piston valve configured to enable the clean fluid to travel from the clean side to the dirty side and to substantially prohibit the downhole fluid from traveling through the piston valve from the dirty side to the clean side.

13. The system of claim 9 , wherein an outer circumference of the at least one piston comprises a chamfer extending between a first axial end of the at least one piston and a radial side surface of the at least one piston and another chamfer extending between a second axial end of the at least one piston and the radial side surface of the at least one piston.

14. The system of claim 9 , wherein an outer circumference of the at least one piston is sized and configured to enable the at least one piston to travel through the at least one tank while at least partially preventing proppants in the downhole fluid from traveling between the outer circumference of the at least one piston and an inner surface of the at least one tank.

15. A piston for at least partially separating at least two fluid streams, the piston comprising:

a body having an opening extending along an axis of the body, the opening defining a fluid pathway through the piston; and

at least one valve obstructing the opening, the at least one valve configured to enable fluid flow in one direction along the fluid pathway through the opening and to at least partially inhibit fluid flow in another, opposing direction along the fluid pathway through the opening, wherein the at least one valve comprises a check valve biased in a closed position toward the one direction, wherein the piston comprises an abrasion resistant material configured to be at least partially buoyant in a fluid.

16. The piston of claim 15 , wherein the opening defines a first recess on a first end of the body and a second recess on a second end of the body, the first recess and the second recess being separated by the at least one valve.

17. The piston of claim 15 , wherein the at least one valve comprises a recess positioned upstream of the check valve.

18. The piston of claim 15 , wherein the check valve is configured to move to an open position when a fluid traveling in the one direction overcomes a biasing force of the check valve.

19. A method of operating a pressure exchange device comprising:

supplying a high pressure fluid to a high pressure inlet of a valve configured to direct flow of the high pressure fluid to a chamber;

transferring a pressure from the high pressure fluid to a dirty fluid through a piston in the chamber;

enabling some of the high pressure fluid to pass through the piston; and

substantially prohibiting the dirty fluid from passing through the piston to the high pressure fluid.