SU556797A1 - Cryosurgical probe - Google Patents

Description

one

The invention relates to medical technology, namely to devices for local cooling, and is intended for experimental and practical surgery.

A known surgical cannula containing a heat-insulated needle, inside of which there are lines for supplying a liquid refrigerant to the inner surface of the heat-transmitting wall of the cooled tip and venting the vapor-liquid mixture to the atmosphere. To increase the heat transfer area on the inner surface of the heat transfer wall of the tip, there are ribs in the form of threads.

In this cannula, between the walls of the line for supplying a liquid refrigerant and the tops of the ribs, there is a space through which most of the refrigerant flows, which prevents the effective removal of gas bubbles formed between the ribs. Drain between these bubbles form portions of the vapor layer that push the liquid refrigerant away from the inner surface of the heat transfer wall of the tip, thereby increasing both the thermal resistance of the heat transfer and the flow rate of the refrigerant.

The purpose of the invention is to increase the freezing capacity of the cryosurgical probe and to reduce refrigerant consumption.

The goal is achieved by the fact that in the cooled tip of the probe, the tips of the ribs are in contact with the outer walls of at least one of the lines in which the holes are made so that the refrigerant has access to the channels formed by the ribs and outer walls.

FIG. 1 shows a cryosurgical probe in longitudinal section with coaxially arranged highways and a tip having ribs along one of the highways; in fig. 2 - section A-A of FIG. one; in fig. 3 - probe with coaxially arranged highways and a tip having ribs made in a spiral; in fig. 4 - section bb FIG. 3; in fig. 5 shows a probe with parallel lines; FIG. 6 shows a section bb of FIG. five.

The probe (flg. 1,3) is hinged from the outer tube 1 forming the body and the inner tube 2, which are vacuum tightly fixed on the tip 3. A high vacuum is formed in the cavity 4 formed between the tubes 1 and 2, which ensures reliable thermal insulation of the surrounding tissue 5 from the refrigerant circulating along a coaxially arranged main line 6 and 7 for supplying the liquid coolant to the tip and draining the refrigerant vapor-liquid mixture from it. On the inner surface of the tip 3 there are ribs 8, made either along highway b (Fig. L), or along a single or multi-pass helix (Fig. 3). The ribs 8, by the vertices 9, tightly adhering to the wall of the highway 6, which serves to supply the refrigerant, form channels 10 isolated from each other, connecting through the openings 11 t to 12 the mains 6 and 7 o

The probe (Fig. 5) can be made so that the vacuum of the cavity 4 is formed by the outer tube 1, the lid 13 and the walls of the lines b and 7, and the inner surface of the tip 3 is provided with ribs 8, which are vertices 9, tight to the walls of the lines b and 7, form channels 10 isolated from each other, connecting through openings 11 and 12 of lines b and 7. In this embodiment, the ribs 8 can be made either in the form of concentric rings, or in the form of a single or multi-pass helix.

The edges of the probe tips can be of any section, for example, rectangular (Fig. 3 and 5) or trapezoidal (Figs. 2, 3 and 5).

During the operation of the probe, the separated refrigerant is divided into several streams isolated from one another, which contributes to the hydrodynamic effect on the bubbles, allowing them to be carried away more quickly, thereby preventing the formation of a vapor layer and contributing to the destruction of the existing ones. This reduces the thermal resistance of heat transfer and provides conditions under which a large part of the liquid refrigerant entering the tip of the cryoprobe is in direct contact with the heat transfer surface, which leads to a decrease in its flow rate. On the other hand, taking into account that the fin edges have a lower temperature due to contact with the cold walls of the lines, the proposed probe provides an earlier transition from film boiling to bubble boiling, which, in turn, helps to reduce the temperature of the tip wall, and therefore , increases its freezing ability.

The use of the described probe allows to increase its freezing ability and to reduce the coolant consumption, which is especially important for autonomous cryosurgical devices.

Claims (1)

Invention Formula A cryosurgical probe containing a line for supplying a liquid refrigerant, a line for removing the vapor-liquid mixture of the refrigerant, placed in a heat-insulated body, and a cooled tip, on the inner surface of the heat transfer wall of which there are fins, characterized in that in order to increase the freezing capacity of the probe and reducing refrigerant flow, in the cooled tip, the tops of the ribs are in contact with the outer walls of the at least one of the pipes, which have holes in them so that ladagent opens into the channels formed by the ribs and the outer walls. // Vue.l YU eight 9ce.2 W ig.Z needles five AT fuz.ff W Vus. AT