| 摘要 |
FIELD: medical equipment, particularly, devices for metered parenteral infusion of liquid drugs. SUBSTANCE: to improve operating characteristics of the apparatus consisting in considerable reduction of liquid pulsation at the apparatus outlet, possibility of use of flexible tubes based on polyvinylchloride without use of silicon inserts, without increasing torque on the shaft of actuating motor, the peristaltic drive has five holding down pins with punches on working ends. Punches are semicircle in section parallel to tube longitudinal axis with radii equalling 1.5-2 of outer diameter of tube, and punches are spaced at 2.5-3 of outer diameter of tube. The first three pins in direction of liquid flow are only forcing and the fourth and fifth are forcing and damping the liquid pulsation. This is achieved due to the fact that the fourth and fifth pins move only half of their working stroke, and the fourth pin closes the tube from half of its working part to full closing, and the fifth pin closes from 0.55-0.7 of the inner diameter of tube to half of its working part. Reciprocation of rods is ensured by cams which are subdivided into four sectors, each of 90 deg. In this case, two opposite main sectors of each cam are made with radii whose difference equals to the pin required stroke, and two other sectors have profiles in the form of Archimedean spiral or parts of circumferences with displaced center connecting the radii of main sectors. Each cam is turned on the shaft relative to each other through 90 deg. Maximum radius of the first four cams is selected to ensure minimum torque on the shaft during start of full pinching of tube that requires minimum radius of cam and limited by the process capabilities in their manufacture. Maximum radius of the fifth radius is less than the maximum radius of the first four cams by a value equalling half of the working stroke of the first three cams. Working stroke in tube working part ranges from 0.55 to 0.7 of inner diameter to its full closing. EFFECT: higher efficiency. |
