Abstract: Apparatus and method of hydrating a particulated polymer and producing a well treatment gel includes a mixer for spraying the polymer with water at a substantially constant water velocity and at a substantially constant water spray pattern at all flow rates of the water. A centrifugal diffuser is connected to the mixer for receiving the mixture, centrifugally diffusing the motive energy of the mixture, and hydrating the mixture into a gel. A centrifugal separator and constant velocity jet pump may be connected between the mixer and the centrifugal diffuser. A dilution valve is connected to the discharge of the centrifugal diffuser for mixing water with the gel at a substantially constant mixing energy at all flow rates of the gel and producing a diluted gel. A viscometer may be connected to the discharge of the dilution valve for measuring the viscosity of the diluted gel and regulating the flow of gel from the centrifugal diffuser to the dilution valve in order to control the viscosity of the diluted gel.

Abstract: A valve includes a seat surrounding an orifice having a concave seating surface and a plug having an annular sealing surface for sealingly contacting the seat. The sealing surface is convex and creates a convex discontinuity in an axially-extending, cross-sectional profile of the plug. The sealing surface retains approximately the same amount of contact area with the seating surface when the plug is misaligned or tilted with respect to the seat as when aligned.

Abstract: A chamber cleaning apparatus and method includes a conduit for conducting fluid into the chamber; a nozzle assembly, connected to the conduit, for creating one of an axial fluid spray to clean the interior surfaces of the first and second end walls of the chamber and a transverse fluid spray to clean the interior surfaces of the side walls of the chamber; a rotational drive assembly for rotating the nozzle means about a rotational axis generally parallel or coaxial with the longitudinal axis of the chamber; an axial drive assembly for moving the nozzle means a preselected distance toward or away from the first end wall of the chamber for each rotation of the nozzle assembly; a transverse drive assembly for moving the nozzle assembly a preselected transverse distance toward or away from the rotational axis for each rotation of the nozzle assembly. A swivel is provided having an outer sleeve body and an inner sleeve body with the inner sleeve body coaxially and rotatably positionable in the outer sleeve body.