Two-spindle screw-spindle pump of single-flow design, having a pump housing which has a pump section, a bearing section and a gear-mechanism section with a gear-mechanism chamber, wherein the bearing section and the pump section are separate from one another, - having a feeder-housing part as a constituent part of the pump section, in which two feeder screws (17, 18) which have flanks and are arranged on shafts (15, 16) are provided, wherein the shafts (15, 16) are mounted in the bearing section and extend into the gear-mechanism section, - having gearwheels (25, 26), which are arranged on the shafts (15, 16) in the gear-mechanism section and by means of which the shafts (15, 16) are coupled for rotation, - having a fastening element, which is arranged on the shaft in operative connection therewith, for establishing a retaining connection between the shaft and the gearwheel, wherein the fastening element and the gearwheel have corresponding bores (36, 37) via which a retaining connection between the gearwheel and the fastening element can be established via a locking element, wherein the screw-spindle pump can be mounted on a drive module, wherein the bores in the fastening element are designed such that the gearwheel and the fastening element can rotate with respect to one another, with the result that it is possible to adjust a distance between the flanks of the feeder screws (17, 18), characterized in that an opening is provided in the gear-mechanism section of the pump housing, in that the opening is provided with a detachable cover, in that the opening is arranged such that the cover can be detached when the screw-spindle pump has been mounted on the drive module, in that, for the purpose of adjusting the backlash of the feeder screws (17, 18), the gear-mechanism chamber can be reached by the requisite tool, and in that the bores in the fastening element are provided in the form of slots in the circumferential direction with a centre line of constant radius, it being possible for the locking element to be displaced therein in the inserted but non-locked state, and in that the length of the slot in the circumferential direction is such that the end points of the slot correspond at least with the points of contact of the flanks of the feeder screws (17, 18) when the locking element is being displaced in the slot. - having a feeder-housing part as a constituent part of the pump section, in which two feeder screws (17, 18) which have flanks and are arranged on shafts (15, 16) are provided, wherein the shafts (15, 16) are mounted in the bearing section and extend into the gear-mechanism section, - having gearwheels (25, 26), which are arranged on the shafts (15, 16) in the gear-mechanism section and by means of which the shafts (15, 16) are coupled for rotation, - having a fastening element, which is arranged on the shaft in operative connection therewith, for establishing a retaining connection between the shaft and the gearwheel, wherein the fastening element and the gearwheel have corresponding bores (36, 37) via which a retaining connection between the gearwheel and the fastening element can be established via a locking element, wherein the screw-spindle pump can be mounted on a drive module, wherein the bores in the fastening element are designed such that the gearwheel and the fastening element can rotate with respect to one another, with the result that it is possible to adjust a distance between the flanks of the feeder screws (17, 18), characterized in that an opening is provided in the gear-mechanism section of the pump housing, in that the opening is provided with a detachable cover, in that the opening is arranged such that the cover can be detached when the screw-spindle pump has been mounted on the drive module, in that, for the purpose of adjusting the backlash of the feeder screws (17, 18), the gear-mechanism chamber can be reached by the requisite tool, and in that the bores in the fastening element are provided in the form of slots in the circumferential direction with a centre line of constant radius, it being possible for the locking element to be displaced therein in the inserted but non-locked state, and in that the length of the slot in the circumferential direction is such that the end points of the slot correspond at least with the points of contact of the flanks of the feeder screws (17, 18) when the locking element is being displaced in the slot.