Liquid Sprayers

Abstract

A liquid sprayer comprises a tubular body with a solid end wall. A transverse slot extends diametrically across the exterior face of the end wall and a hypodermic tube extends through a drilling intersecting the slot. The ends of the tube are seated externally of the body and it is formed adjacent its ends with openings inside the body. Within the slot a discharge slot is formed in the tube. The body is contained in an air casing with air discharge ports to create a flat fan-shaped air flow pattern enclosing the flat fan-shaped liquid spray pattern produced by the discharge of liquid from the slot.

Description

This invention relates to liquid sprayers and has as an object to provide a sprayer in a convenient form.

A sprayer in accordance with the invention comprises a tubular body having a solid end portion formed with a slot extending across said end portion, a fine tube situated in a drilling intersecting said slot, a transverse discharge slot formed in the tube within the slot in the end of the body, and a pair of entry slots formed in the inner surface of said solid end portion of the body and in the tube at diametrically opposite positions, the ends of the tube being pinched together and welded or otherwise sealed externally of the body.

An example of the invention is shown in the accompanying drawings in which:

FIG. 1, is a section through an example of a liquid sprayer in accordance with the invention;

FIG. 2 is a section on line 2--2 in FIG. 1;

FIG. 3 is a section on a smaller scale showing the sprayer in position in a burner head;

FIG. 4 is an elevation of the burner head shown in FIG. 3 partly in section; and

FIG. 5 is a sectional view on a still smaller scale of the burner head installed in a combustion chamber.

Referring first to FIGS. 1 and 2, the liquid sprayer comprises a tubular body 10 which has a solid end portion 11. A transverse slot 12 extends diametrically across the outside face of the end portion 11. A hypodermic tube 13 extends through a diametral drilling in the end portion 11 intersecting the slot 12 at right angles. The hypodermic tube has its ends brazed or otherwise secured in position in the drilling. A liquid discharge slot 14 is formed in the tube 13 in alignment with the axis of the slot 12, it being noted that the depth of the slot 14 is slightly less than the radius of the tube 13. To allow liquid from the body 10 to enter the tube 13 there are a pair of diametrically opposite arcuate entry slots 15 which are formed by spark erosion after the tube 13 has been fixed in position, but before the slot 14 has been formed. The entry slots 15 extend both through the end portion 11 of the body 10 and through the tube 13. The ends of the tube are pinched together externally of the body 10 and then welded to seal the ends of the tube thoroughly.

The sprayer is made by inserting the tube 13 through the drilling in the end portion 11 of the body after the slot 12 has been formed therein. The tube 13 is then brazed in position at its ends and the slots 15 are then formed, as mentioned above, by spark erosion. The slot 14 is then formed and the tube 13 is then cutoff close to the outside surface of the body 10 and its ends are pinched together and welded.

The sprayer body 10 is secured in use at the end remote from the end having the hypodermic tube 13 to a burner body 17 which has a fluid inlet 18 incorporating a strainer 19. Also secured to the burner body 17 is an air casing 20 which surrounds the body 10. The casing has an air inlet 20a in its sidewall and its end wall is shaped to provide a pair of air discharge ports 21 which direct, in use, jets of air across the outside face of the end portion 11 of the body 10 from diametrically opposite positions. As will be seen from FIG. 4 the external surface of the end of the air casing 20 is formed with a rib 22 extending diametrically thereacross. The internal surface of the end wall of the air casing 20 is formed, by electro erosion or otherwise, with a diametral groove 23 extending inside the rib 22. The body 10 fits into this groove 23 with the axis of tube 13 parallel to the length of the groove 23. A transverse groove 24 is cut diametrically across the exterior of the end wall of the air casing 20 thereby opening the groove 23 to the exterior of the air casing. The ports 21 are thus formed by the combination of the body 10 with the air casing 20.

The sprayer is designed to produce a flat liquid spray pattern and the air jets from the ports 21 form a flat airflow pattern of shape and orientation similar to the spray shape. The assembly described above is of particular utility in small size gas turbine engines where very low fuel pressures exist during idling. In addition the problem of obtaining effective atomization is made worse since available air pressures are also extremely low. As shown in FIG. 5 the burner head is installed in the double wall of a gas turbine engine combustion chamber. The inner wall 25 of the combustion chamber has an opening into which the air casing fits and the burner body fits into an opening in the outer wall 26. Thus the air inlet 20a opens into the air jacket 27 to which air is supplied before passing into the combustion zone through various openings in the inner wall 25. The ports 21, on the other hand, open into the interior of the inner wall. During idling the minimum air pressure drop across the inner wall 25 which may be expected is in the region of only 21/2 inches (63.5 mm.) water gauge. At the same speed the fuel pressure may be as low as 1 p.s.i. (70g./CM..sup.2). Even under these adverse conditions satisfactory atomization can be obtained from the burner head described.

Claims

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A liquid sprayer comprising a tubular body having a solid end portion formed with a slot extending across said end portion, a fine tube situated in a drilling intersecting said slot, a transverse discharge slot formed in the tube within the slot in the end of the body, and a pair of entry slots formed in the inner surface of said solid end portion of the body and in the tube at diametrically opposite positions, the ends of the tube being pinched together and welded or otherwise sealed externally of the body.

2. A liquid sprayer as claimed in claim 1 further comprising an air casing surrounding the body and having an end wall formed with a slot parallel to the slot in tubular body, said air casing having an inlet and a pair of ports opening into the slot therein from opposite sides.

3. A liquid sprayer comprising the combination of a tubular body having an open end and an end wall at the other end, said end wall having a diametral passageway open at both of its ends to the interior of the body and a transverse discharge slot opening from the passageway onto the exterior of the end wall at the center thereof, said passageway being a fine tube located in a drilling in the body end wall intersecting a transverse slot in the exterior of the body end wall, the discharge slot being in the tube within said transverse slot, whereby, when liquid is introduced into the interior of the body at a sufficient pressure, an atomized spray is ejected from the discharge slot in a flat fan-shaped spray pattern, and an air casing surrounding said tubular body, said air casing having an air inlet and the air casing and the tubular body being shaped to define therebetween a pair of oppositely disposed air discharge ports which discharge air streams parallel to the passageway in the body to create a flat fan-shaped airflow pattern enclosing the spray pattern and assisting in atomization of the liquid.

4. A liquid sprayer as claimed in claim 3, in which the air casing has an end wall formed externally with a diametral rib and with a groove transverse to said rib and internally with a diametral groove within said rib, the tubular body fitting into said internal groove with the discharge slot parallel to the external groove in the air casing.

5. Combustion apparatus for a gas turbine engine comprising an outer wall to the interior of which air is supplied, an inner wall within said outer defining a combustion zone within said inner wall, said inner wall having a plurality of openings through which air passes into the combustion zone, and at least one burner head mounted on the outer wall and projecting through a hole in the inner wall, said burner head comprising a tubular body with an end wall having a diametral passageway open at both ends to the interior of the body, and a discharge slot transverse to said passageway and providing communication between the passageway and the combustion zone, means for ducting fuel under pressure to the interior of the tubular body, and an air casing surrounding the body and engaged with the inner and outer walls and formed with an air inlet disposed between said inner and outer walls, the body and the air casing being shaped to form between them a pair of oppositely disposed air discharge ports for directing streams of air towards one another in directions parallel to said passageway adjacent said discharge slot.