US1729577A

US1729577A - gastell

Info

Publication number: US1729577A
Authority: US
Publication date: 1929-09-24
Anticipated expiration: 1946-09-24

Description

'sepL 24, 1929. F. GASTELL 1,729,577

BLAST NOZZLE Filed June l5, 1928 lnrenfar jij-ff Patented Sept. 24, 1929 UNlTED STATES PATENT FFICE BLAST NOZZLE Application filed June l5, 1928, Serial No. 285,671, and in Germany June 21, 1926.

The subject matter of the present invention is a nozzle or blast-pipe arrangement, and a method of working; the same, for blowers or blast apparatus of the kind in which the materials to be blown out or sprayed, such as sand, steel balls` concrete masses, met-a1 etc., areI carried forward, by the action of a stream of compressed air. gas, steam or the like moving' forwards with great speed in a. tube or lo pipe, as constituents to be mixed with the stream of air. steam or `ras expanding at the outlet end of the nozzle, and thereby perform work.

Hitherto, the mixture of compressed jras and materials to be blown or sprayed out has frequently been moved forwards in a nozzlebody which narrows continuously toward the outlet openingr and is often cylindrical, and separate nozzle tubes of conical or cylindrical form for conducting the gas and the materials to be blown out have only seldom been employed. In the former case the Wear on the nozzle is great, and in both cases the speed of the stream of the mixture of gas and materials to be sprayed out or of the gas alone lowing;` through the nozzle passages decreased greatly as it approached the outlet opening, so that the maximum attainable outlet speed of the blast could not be usefully :o employed. These disadvantages increased to such an extent at gas pressure exceeding two atmospheres that the employment of gas pressures exceeding the aforesaid maximum ressure was precluded to a great extent rom 5 reasons of economy. If for special reasons high pressures above two atmospheres had to be employed this was done only in exceptional eases. Nevertheless an increase of pressure would be preferable for many rea- 0 sons, if the results obtained were on a similar sca-le to those obtained with pressures below two atmospheres with respect to increased performance and wear on the nozzle.

The object of the present invention is to 5 solve this problem, while maintaining separate passages for the conduction forward of the compressed gas and materials t0 be sprayed out which only unite at the outlet where they are co-axial, by continuously wid- J ening the gas passage towards the outlet opening, so that the cross-sectional. area of the passage and thereby the speed of the air or gas and with it the spraying,r effect continuously increases, that is to say the action is similar to that of the de Laval nozzle.

A nozzle for carryingr out the aforesaid method of operation is illustrated by way of example in the accompanying drawing.

Referring to the drawing, the pipe l serves for the conduction of compressed air and the pipe 2 for the conduction of sand from any suitably arranged vessel. The pipe l runs at the back of the device at an angle to the pipe 2. It is then formed with a bend and provided with a threaded {la-nge 3, which serves for the reception of the pipe 2, and runs further forwards co-axially with the pipe 2 which it then encases. The cross section of the free annular space between the two tubes increases continuously towards the front from a narrowest part l, so that the air passage is greatest at the outlet end like a de Laval nozzle.

The sand fiowing through the tube 2 reaches the outlet 4 owing to the suction of the escaping stream of air and is thence carried along by the escaping air with a speed which corresponds to the full pressure of the air.

It is known'that, owing to the widening from I to II the effect of the pressure prevailing in the tube l is increased, in so far as the speed of the air at the outlet l is considerably above the normal speed, the spraying effect which depends on the square of the outlet speed is therefore considerably increased.

By means ofthe new arrangement the airpressure is fully utilized, and any wearing out on the nozzles, pipes or other parts is eliminated. The new implement can be'used for similar processes in which, as in spraying with mortar, cement, metal, or even with acids, colours or the like, the advantages of the new process can be utilized;

What I claim is A blast nozzle for blowing apparatus in which solid materials such as sand, steel balls, concrete masses, metal and the like are sprayed by the suction of a compressed fluid,

comprising a tubular member for conveyin the solid materials to the nozzle outlet, an a. tubular member for conve ing the compressed iluid to the nozzle out et, said second tubular member approaching the first-mentioned tubular member at an an le and gradually curving into parallelism t erewith, and enclosing the first-mentioned tubular member, along the parallel part thereof, with an annular gap between, the inner tubular member which conveys the solid material, at flrst increasino in wall thickness from the place at which the wall of the outer tubular member, which conveys the compressed fluid, becomes parallel thereto,and both tubular members uniformly decreasing in wall thickness over the latter part of their length, without any alteration occurring in the external diameter of the outer tubular member or in the internal diameter of the inner tubular member.

` In testimony whereof I have signed my name to this specication.

. FRANZ GASTELL.