US2674493A

US2674493A - Atomizer

Info

Publication number: US2674493A
Application number: US605862A
Authority: US
Inventors: Franz J M Raskin; Kingsley L Martin
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-07-19
Filing date: 1945-07-19
Publication date: 1954-04-06
Anticipated expiration: 1971-04-06

Description

April 1954 F. J. M. RASKIN ET AL ATOMIZER 2 Sheets-Sheet 1 Filed July 19, 1945 TORS Fpmz JIM/64544 IN VEN flmaszgyL/ her/nl April 6, 1954 F. J. M. RASKIN ET AL 2,674,493

ATOMIZER Fileu July 19, 1945 2 Sheets-Sheet 2 BY WM Patented Apr. 6, 1954 Franz J M.:Raskin,

Montreal, Quebec, Canada,

and Kingsley L. Martin, Nutley, N. J 'Application'lluly 19, 1945, Serial No. 605,862

1 Claim.

This invention relatesto a device for atomizing a liquid by pressure alone wherein a wide range in capacity combined with-'suffioiently fine atomization and an approximately constant spray angle is obtained by maintaininga fixed discharge orifice but changing the shape andareas of the tangential slots and the whirling chamber so as to obtain the desired results without substantial change in the pressure of the liquid supplied to the atomizer or diversion of any liquid from the whirling chamber.

This invention is an improvement on and relates to liquid fuel atomizers of the type described in the specification of'U. S. Patent No. 2,044,091 issued June 16, 1936, to Kingsley L. Martin.

In the'specification of said prior patent several means were described forobtaining suitable atomization over'a wide range of capacities.

These means were: (1) use of a stationary spindle in the orifice to utilize the more rapidly moving elements of rotating oil issuing from the whirling chamber without changing either the area of the orifice or of the tangential slots, (2) use of a l .oveable spindle to change the orifice area without changing the area of the tangential slots, and (3) use of a moveable spindlewith a disc attached to and moving with it by means of which the discharge area of the tangential slots was changed at their outlets into the whirling chamber simultaneouslywith the change in orifice area. It was specified that the units might also be designed so as to maintain-a constant. ratio between the orifice andeifective tangential slot areas.

We have found that a modification of the latter method produces materially'better results. The novel details of construction and combination of partsnecessary to produce these results are fully shown and described in the accompanying drawings and the following specifications and claim.

Referring to the'drawings forming part of the specifications in which like numbers designate like parts in all the views.

Fig. 1 is a longitudinal section of .theatomizer, taken on the broken line II of Fig. 4, showing the central moveable plug in its innermost position with respect to the orifice, giving maximum capacity; Fig. 2 shows the plug in halfway position, giving intermediate-capacity; and Fig. 3 is a longitudinal section on the broken line III-III of Fig. 5, showing the plug in its outermost position, giving minimum capacity.

Fig. 4 is a cross section of the forward end of the moveable plug andsprayer platetaken on the lineIV-IV of Fig. 1', showing the tangentialslots in the sprayer plate-before the finsententhem; Fig. 5 is a cross section taken onitheline V-.V. .of Fig. 3, after the plughas: been advanced showing the tangential slots occupiedby the fins; Fig. 6. is an elevation of the sprayer plateshowingta-ngential slots, whirling chamberandorifice; .Fig. .7 is an end view of the-same; Fig. 8 isan. end view of the moveable plug shown Fig. 9; and Fig. 9 is an elevation ofthe moveableplug.

In Figs. 1, 2 and 3, I is aisupplyapipefor. the liquid to be atomized,.having .screwzthreadsiiZ and bore 3. The atomizer body l :is screwed on the pipe I. Seated againstthe outer end of the atomizer body a is a sprayer .plate .5..securedi.in position by nut is which is threaded-onvbodyfi. The sprayer plate 5 is provided with a rearwardly extending cylindrical portion forming a. cylindrical chamber 1 terminating inaconicalchamher as in the body portionof. theplate, .the chambers l and 8 together constituting the whirling chamber.

In the cylindrical portion ofthesprayeryplate are multiple tangential slots 91their forward sides being inclined as shown in Figs. 1, 2,,-and,;3. In the front transverse face 10 .ofx-the plate, isa cylindrical orifice l l. On the inside of the wall of the body 4 are longitudinalpassageways I8 communicating at their forward ends with an annular space ltd around the back end of the sprayer plate 5 and at'therear ends-through holes ltb with chamber 130. The tangential slots 9 in the sprayer plateconnectitheannular space lea, at their outer endawith the. whirling chamber 'l8, at their inner ends.

A rod l2 carries a cylindrical plug I3, the forward part of which is first reduced in diameter as at M and then terminated in acone l5. Integral with or attached to the face of the reduced section l4 are projecting 'fins [6. corresponding in number to the tangentialwslots 9. .These ,fins it slide in and fit closely the tangential slots, 9 and are beveled on the leadingedgetothe same slope as the conical portion ofytheplugl3 and forward sides of the tangential slots.

The central plug is therefore capable'of being progressively advanced by the-rod 12 from the position in Fig. 1 where the tangential slots are of their greatest area, 'throughthe; position shown in Fig. 2, where the slots are. ofza. diminished. area by reason of the advance of the finsin :theslots, and thence to the position shownin Fig. B'WhBIE the slots are substantially closedbythe-fins.

It should be particularly noted that the .front side and the longitudinal sidesof ithestangential slots are fixed-while the rear side-ofeachslot is formed by the inclined edge of a. fin l1 so that the area. of each tangential slot is progressively decreased as the plug carrying the fins advances the whole depth of each slot and the slot area is not reduced at one point only.

The liquid to be atomized enters through the supply pipe I and flows through the longitudinal passageways l8bl8, in the inside wall of body 4 into the annular chamber lBa and thence through the tangential slots 9 into the whirlin chamber 'I8, from which it is discharged through the orifice ll.

Due to the direction of the slots 9 and their small cross section the liquid enters the whirling chamber tangentially at a high velocity and. rotates the liquid in the whirling chamber at very high velocity so that it issues from the orifice in the form of a hollow cone spray of finely atomized liquid. The fineness of the atomization and its included angle are both highly important.

The fineness of atomization is due primarily to the rotational velocity of the liquid in the whirling chamber. This velocity is due in turn to the mass velocity of the liquid entering the whirling chamber from the tangential slots. This we have found to be greatest and most effective when the cross section of the tangential slots is reduced throughout their whole length instead of at their exit into the chamber.

Therefore in this invention we have used fins located in deep tangential slots and reduced the areas of the slots throughout their whole length, forming solid jets of liquid travelling at high velocity which produce and maintain a high circular velocity of the liquid in the whirling chamber.

A further improvement on the previous invention is obtained by progressive change in the ratio between the area of the orifice and the total area of the tangential slots obtained at different positions of the movable plug. As is well known, the higher the ratio (obtained by dividing the slot area by the orifice area), the coarser the atomization and in atomizers heretofore used, the narrower the included angle of the spray.

In this invention, advantage is taken of the fact that in burning liquids in a furnace, at high capacities the temperature of the furnace is always high, due to the heat developed by the large quantity of fuel being burned. The velocity of the air for combustion entering through the register with the spray is also high and its ability to penetrate and mix with the liquid in the spray is correspondingly great. Consequently coarser atomization at high capacities is permissible and is often necessary to avoid the tearing apart of the spray or of too much change in flame angle by the high velocity air.

Since the orifice area remains constant until the pointed end of the plug enters the orifice as in Fig. 3 and the area of the tangential slots is progressively reduced by the movement of the fins from a maximum in the inward position of the plug with respect to the orifice, as in Fig. l, to the minimum, in the closed position as in Fig. 3, it follows that the ratio is correspondingly decreased and the fineness of atomization is correspondingly increased at a time when the lower temperature of the furnace and the lower velocity and lower penetrating power of the air for combustion makes this desirable.

It is evident that the parts of the atomizer may be designed to cause the point of the plug 15 to enter the orifice H at some point in the plug movement at which further inward movement of the plug will simultaneously reduce the area of the orifice and the slots thereby maintaining a nearly constant ratio at the lower ca- 5 pacities if that result is desirable, as it is in some applications.

It has been previously stated that a constant spray angle is generally desirable and that heretofore this angle has usually been affected by changes in capacity. This has been largely the result of maintaining, through the obtainable range in capacity, constant areas of the orifice, slots and the volume of whirling chamber.

In this invention, in addition to changing slot areas, the whirling chamber shape and volume are changed. In Figs. 1, 2 and 3, the whirling chamber is shown composed of a cylindrical space I, with center occupied by conical point l5 of the moveable plug l3, and a truncated conical space 8 continuous therewith. This chamber is progressively reduced in volume and the proportion of cylindrical volume to the conical volume changed as the plug moves forward. Simultaneously the slot areas are reduced.

Since the quantity of liquid being rotated in the whirling chamber is thus progressively reduced in proportion to the reduction in quantity of oil flowing through the slots, the high rotational velocity of the liquid is maintained by the diminishing jets from the slots and the tendency is to maintain the spray angle constant as the capacity decreases instead of its being reduced. This effect is further accentuated by the sharp increase in liquid velocity through the slots which takes place, as their area is decreased, as a result of the increase in pressure drop through the slots since the pressure at their entrance is maintained constant while the pressure at their exit into the whirling chamber is progressively reduced.

A third factor in the preservation of the spray angle is the shape and position of the plug point l5. As the plug advances, its inclined face is interposed in the path of the liquid issuing from the slots so as to progressively convert an increasing part of the tangential velocity into longitudinal velocity i. e. from velocity of rotation to velocity of translation, tending to narrow the spray and thereby counteracting to the desired extent the tendency resulting from the reduction in ratio and increase in slot velocity to widen the spray. By proper design, it has been found possible by balancing the component elements to maintain substantially constant spray angle at all capacities.

It will be noted that in this invention, all the liquid supplied to the atomizer leaves through the orifice and none is taken away from the whirling chamber or otherwise disposed of. When the liquid has been highly heated, as in the case of fuel oil and other viscous fuels the elimination of return liquid is highly advantageous.

It is obvious that those skilled in the art may vary details of construction as well as the arrangement of the parts without departing from the spirit of the invention. I, therefore, do not wish to be limited to the-above disclosure except as may be required by the claim.

What I claim is:

An atomizer having a portion adapted for connection to a source of liquid supply; said atomizer being provided with a whirling chamber having a cylindrical rear portion and a conical front portion provided with an outlet orifice at its apex; the side wall of said cylindrical portion being provided with a slot passing therethrough from its radially outer side to its radial- 1y inner side, said slot communicating along its outer end with said portion adapted for connection to the source of fluid supply; said slot being tangentially disposed at its inner end with respect to the cylindrical surface of said chamber, the front side of said slot being inclined at an angle corresponding to that of the slope of the surface of said conical portion of the chamber and in alignment therewith; and a slidable plunger with cone-shaped face of the angularity of the cone-shaped portion of the whirling chamber, said plunger being provided with a fin extending into said slot, the front side of said fin being in alignment with the cone-shaped face of said plunger.

References Cited in the file of this patent UNITED STATES PATENTS Number 5 1,060,164 1,102,352 1,180,907 1,439,320 1,571,629 10 1,904,509 2,044,091 2,372,283

Number 15 447,053