Abstract: A heater treater apparatus includes a vessel, a burner for heating a material contained in the vessel, an air intake passage for directing air to the burner, a flame arrester operatively associated with the air intake passage for preventing flames from the burner from extending past the flame arrester, and an air damper for controlling a flow rate of intake air drawn through the flame arrester. The air damper includes a fixed circular first plate having a first plurality of circumferentially spaced plate openings therethrough, and a similarly constructed rotatable circular second plate. The second plate may be rotated relative to the first plate from an open first position to a second position wherein the plate openings of the first plate are at least partially blocked by the second plate.

Abstract: Apparatus and methods are provided for installing and removing a downhole rod pump form a well while preventing flow of fluids from the well through a production tubing string.

Abstract: A railway car truck having side frames with an opening for receiving the ends of a bolster, and spaced columns with removable wear resistant wear plates, secured thereto and retained by L-shaped retainers at the corners.

Abstract: To prevent vertical disengagement of the knuckles of railway car couplers, for example type "E" couplers, a vertical upward extension is provided on the forward nose of the knuckle which terminates in a shelf extending over the buffing face of the nose. The pulling face of the extension tapers upwardly toward the buffing face to allow for vertical angling thereof.