| 摘要 |
<p>The invention relates to a filter for solids, mounted in a bore hole for trapping solid particles that can be found in the fluid coming from an oil layer, that is extacted to the surface by means of a well pump. According to the invention, the filter consists of a shell (1) provided with a filtering region (a) formed by some through slots and an inner tube (2) provided with some annular orifices (b), having the centre located on a circular circumference in two antipodal points, and on the adjacent circumference, located at a distance of 4 to 5 diameters of inner tube (2) away from said circumference, also in two antipodal points, but 90A shifted in the horizontal plane relatively to the first two, so that the orifices (b) form, on the outer side of the inner tube (2), four rows lengthwise of four generatrices situated at 90A in the horizontal plane. The diameter of orifices (b) on the same row is decreasing from the bottom side towards the upper side of the filter, their values forming a geometric progression defined by the relation (q), q =0.09*In(L f) + 0.69, wherein L f is the length of the filter where the orifices (b) are practiced, the diameter of the first orifice (b) at the bottom being in the range from 0.75 to 0.9 of the diameter of an orifice (c) on the production casing (3), to the outer side of the inner tube (2) there being secured some spacers (4) whereon the shell (1) is rigidly secured, thereby forming an annular space (d) having the role of hydraulic accumulator along the fluid path, the volume thereof being 5 to 6 times bigger than the volume of the fluid pumped on a stroke of the piston well pump.</p> |
