Patent GB-392534-A (GB)
Title: Improvements in sand bailers for use in wells
IPC: E21B27/00
Filed: 1931-11-14
Abstract: 392,534. Bucket-elevator apparatus. CAVINS, O. A., Taft, California, U.S.A. Nov. 14, 1931, No. 31591. Convention date, Nov. 14, 1930. [Class 102 (ii).] Means for removing sand &c. from wells comprises a sand chamber with a bottom inlet, a chamber above the sand chamber and containing air, gas or both at low pressure, means closing communication between the two chambers while the device is being lowered into the well, and means for opening such communication when the device strikes an obstruction, the pressure in the well then causing a rush of fluid &c. towards the second chamber and thereby carrying sand into the sand chamber. In Figs. 1 and 2, the sand chamber 2 has at the lower end an inclined flap valve 4 and a shoe 3 wich a sleeve 5 adjustably threaded to the sand chamber whereby apertures 33, 34 in the sand chamber and sleeve 5 respectively may be brought into register for discharge of the sand chamber. The pressure chamber 10 is normally closed to the sand chamber by a ball valve 7 provided with a stem 12 pressed upwardly by a spring 21 and threaded to a polished rod which passes upwardly through a stuffing box 25 and has at its upper end a head 13 ; excess pressure in the chamber 10 is relieved through spring-pressed valves 27. Above the head 13 of the polished rod is a slidable grooved block 14 guided by a pin 17 and provided with a slidable latch 18 co-operating with a cam 20 for movement below a shoulder 22. Wash-holes 30 are provided for cleaning out sand. In use, the device is lowered into the well and on reaching the bottom, the momentum of the block 14, assisted if required by that of an upper member 93, moves the valve stem 12 downwardly to open the valve, the latch 18 engaging the shoulder 22 to hold the valve 7 open; the pressure in the well then forces material past the flap valve 4 and compresses the gas in the chamber 10. On removing the device from the well, slots 35 in the shoe are engaged with a bar 36 and the device rotated to align the ports 33, 34, the pressure in the chamber 10 then effecting discharge of the sand chamber 2. The device is then reset by inserting a pin through an aperture 23 to free the latch 18. In a modification, Fig. 6, in which the working parts are concentrated in three separable units for ease of transport, the sand chamber has an upper sleeve 43 slidable on the lower end of the pressure chamber, a spring 45 pressing the members apart and a collar 41 limiting such motion. Communication between the sand and pressure chambers is normally closed by a valve 48 connected above to a plunger 50 open above to the pressure in the well so as to balance the upward pressure on the valve. A spring 54 tends to keep the valve 48 closed. In use, when contact is made with the bottom of the well, sliding movement of the sleeve 43 occurs, the sleeve then engaging a cross-head 53 whereby the valve is opened. Communication with the pressure chamber is thus opened through vertical ports 57 and the sand chamber is filled. On removal from the well, the device is emptied by opening the discharge ports as in Fig. 1 and lowering the device on to the derrick floor so as again to cause sliding of the sleeve 43 and opening of the valve. At the upper end of the pressure chamber, adjacent the lifting bail 68, Fig. 7, a pressure relief valve 64 may be provided ; a tube 63 depends below the valve to form a gas trap. In a similar form, Fig. 9, the sliding movement effects opening of the valve 108 by contact with stops 116 on a rod 109 depending from the valve ; the flow area to the pressure chamber is varied by inserting plugs 120 in one or more of the flow ducts 104, the plugs being threaded or held by an upper tube. For use in crooked wells, the sand chamber is formed of armoured hose 85, Fig. 11, and the upper parts of the device are connected by ball and socket joints 77, tie wires 80 preventing loss of parts in case of fracture.