Patent GB-770994-A (GB)
Title: Cooling process and device for the performance of same
IPC: H01J19/36
Filed: 1953-01-19
Abstract: 770,994. X-ray tubes; electrode materials. VIERKOTTER, P. Jan. 19, 1953 [Jan. 23, 1952 ; Jan. 23, 1952 ; Dec. 15, 1952], No. 1510/53. Class 39(1). A process for the cooling of bodies, particularly the anodes of discharger tubes such as X-ray tubes, by means of a coolant jet is characterized in that an intermediate layer is provided between the surface of the body to be cooled and the infringing coolant jet, at least at those parts of the surface of the body on which a stream of coolant impinges, the molecular weight of the intermediate layer being approximately equal to the molecular weight of the material of the body surface to be cooled and to that of at least one component material of the impinging stream of coolant, the component material possessing good thermal conductivity and being rapidly removed from the zone of impingement when it has absorbed heat. The principle of the invention is illustrated in Fig. 1 in which the surface 2 of the body 1 to be cooled is provided with a layer 3 of material of good thermal conductivity on which impinges a jet of coolant 4 consisting of liquid and/or gaseous and/or solid materials, at least one component 8 of which consists of material of good thermal conductivity for abstracting from the layer 3 heat received from the body 1. The component material of good thermal conductivity may be a suspension of a finely divided substance, such as a metallic powder, in a liquid, or a celloidal solution or a finely divided substance entrained in a gas. The component material may be continuously admixed to the.composite coolant in a constant volumetric ratio which may be regulated manually or automatically in dependence on the operating conditions such as the temperature of the body surface to be cooled or the quantity of beat abstracted by the coolant. The component material may be produced prior to the impingement of the coolant on the intermediate layer by chemical interaction of liquids and/or gases. The coolant can also contain liquid or gaseous components which form a protective layer or atmosphere in the vicinity of impact of the coolant. The intermediate layer 3 can be formed by vaporization in a vacuum, cathodic atomization, adsorption, absorption, diffusion, by electrolysis and electrochemical processes, by chemical methods, by baking, by surface treatment with melted substances, by rubbing in or can be formed as referred to below during the cooling process. Fig. 2 shows the principle of the application of the invention to an X-ray tube the face 2 of the gold anode 1 being provided with a layer 3 of gold amalgam on which a jet 4 of, or containing, mercury impinges. The jet 4 is formed by a pipe 15 having a coil 16 to provide rotation. The layer 3 of gold amalgam can be formed on surface 2 by the jet 4. The coolant after impingement on the surface 3 is conducted to a stationary or flowing coolant 17 of some other material such as water. The coolant may comprise a stream of gas having a high content of mercury vapour. An application to X-ray tubes is shown in Fig. 4 in which mercury supplied through the tube 40 to annular chambers 39-33 is applied as jets 41 over the coils 16 to the rear face of the hollow conical anode 18 with shoulders 30, 31. Water is supplied through the pipe 42. The water is supplied to the anode below the stream of mercury so that only the mercury comes into direct contact with the anode. The water and mercury together pass into the chamber 46 having a baffle 46a where the mercury is conducted away through a U-tube 47 whilst the water is drained off by the pipe 48, the water and mercury being circulated through a system including a water reservoir, with filter and a regulable water feed, and a duplex eccentric pump. The X-ray tube is shown in Fig. 3 and comprises the hollow conical anode 18 fused into a copper ring 19 screwed on to the cooling device 21 referred to above and fused into a glass cylinder 22. The cathode 23 with filament 24 is sealed off by a filter 25. The tube window 26 is mounted on supports 27 and has a screen 28 before it. A protective screen 29 which 'may contain a filter rests on the glass cylinder 22. The anode may comprise several layers of different materials.