US3831858A

US3831858A - Vented plunger atomizer

Info

Publication number: US3831858A
Application number: US00337037A
Authority: US
Inventors: R Casey
Original assignee: US Department of Navy
Current assignee: US Department of Navy; Waukesha Foundry Co Inc
Priority date: 1973-03-01
Filing date: 1973-03-01
Publication date: 1974-08-27
Anticipated expiration: 1991-08-27

Abstract

Fluid pressure in a variable volume whirl chamber exerts a force that positions a spring biased piston. The positioning of the piston determines the amount of fuel oil supplied to a ship''s boiler by an arrangement of ports in a whirl chamber cartridge. The cartridge provides an enclosure for the whirl chamber, a piston and a biasing spring. The fuel is delivered axially along the outside of the cartridge through the ports to the whirl chamber and out an orifice located at the forward end of the whirl chamber.

Description

fiasey tes tent [19.1

[ Aug. 27, 1974 VIENTED PLUNGER ATOIVHZER [75] Inventor: Robert ,5. Casey, Philadelphia, Pa.

[73] Assignee: The United States of Ameria as represented by the Secretary of the Navy, Washington, DC.

22 Filed: Mar. 1, 1973 211 Appl. No.: 337,037

[52] US. Cl. 239/464 [51] Int. Cl. B051) 1/34 [58] Field of Search 239/464, 533

[56] References Cited UNITED STATES PATENTS 2,661,243 12/1953 Fox 239/464 3,669,354 6/1972 Helyer 239/464 R20,027 6/1936 Wettstein 239/464 FOREIGN PATENTS OR APPLICATIONS 581,367 10/1946 Great Britain 239/464 Primary ExaminerLloyd L. King Attorney, Agent, or Firm-R. S. Sciascia; Henry Hansen [5 7] ABSTRACT Fluid pressure in a variable volume whirl chamber exerts a force that positions a spring biased piston. The positioning of the piston determines the amount of fuel oil supplied to a ships boiler by an arrangement of ports in a whirl chamber cartridge. The cartridge provides an enclosure for the whirl chamber, a piston and a biasing spring. The fuel is delivered axially along the outside of the cartridge through the ports to the whirl chamber and out an orifice located at the for ward end of the whirl chamber.

9 Claims, 4 Drawing Figures VENTED PLUNGER ATONHZER STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION The present invention generally relates to fluid atomizers and more particularly to a vented plunger atomizer for supplying fuel oil to a ships boiler wherein the atomizer has a variable volume whirl chamber in which the amount of fuel used is a function of fuel supply pressure.

The development and evaluation of fuel oil burners for naval main propulsion boilers has long been pursued by the U.S. Navy. A report of the U.S. Naval Liquid Fuel Board made under the direction of RADM G. W. Melville, USN, published in 1904 is an early manifestation of this. The report was concerned with boiler tests which were conducted to show the relative evaporative efficiencies of coal and liquid fuel. As a part of this, the report presented an excellent summation of oil burner development to that time. The word atomization was coined by Comm. Isherwood of the U.S. Navy in this report. The need was mentioned for mechanical atomizers for which compressed air or steam consumption would not be necessary. The disadvantages of steam atomization for marine applications due to the fresh water consumption and that of air atomization due to the bulk of the equipment required and accompanying maintenance was recognized.

A mechanical atomizer as we know it, using a rotational element or tangential slots to whirl the oil through an orifice plate was introduced about 1902. This was a milestone in the development of oil burning for marine purposes since it removed the disadvantages of steam consumption and extra equipment associated with steam and air atomizing burners. However, this type atomizer has a very limited tumdown range. This necessitates the use of several different atomizer sizes to span the full range of naval boiler operation which is a great disadvantage.

The return flow mechanical atomizer had its beginnings in 1921. The system the U.S. Navy uses with this atomizer is commonly known as the 1,000 psi return flow system. It has the great advantage of wide range operation without changing atomizers and has been a great boon to boiler automatic combustion control. However, it has the disadvantage of utilizing a very high fuel pressure which presents a potentially hazardous condition in the fireroom. In addition, except at maximum oil rate, the oil pump is required to supply more oil to the atomizer than is actually being burned. Thus, a heavy load is placed on the fuel oil pump which is very undesirable, especially in light of the present conversion to distillate fuel.

Steam atomizing burners have been utilized in some U.S. Navy ships in recent years and have performed very well. They have the advantage of a very wide range of operation and a low fuel supply pressure (350 psi). In addition, all the fuel pumped to the steam atomizing burner is burned, none is returned. However, the steam used for atomization goes up the stack with the flue gases and is a loss of makeup feedwater.

For producing a finely atomized spray, many variable volume whirl devices have been designed. In such a device, the whirl chambers volume becomes a function of the demand of the burner. In such a setup, an increase in demand is translated into an increase in the pressure of the fuel supply which, in turn, causes an increase in the flow of the fluid to the whirl chamber.

One such device for obtaining the above result uses a separate space for producing the fine spray from that used to determine the quantity of fuel to be used. This leads to a large device with numerous components.

Another type uses a plurality of whirl chambers, plungers, separate ports for each chamber and a large number of other duplicate components for maintaining a fine fuel spray. These devices tend to unnecessarily complex having an unwarranted number of components that also add to the bulk of the device.

SUMMARY OF THE INVENTION Accordingly, it is a general purpose and object of the present invention to provide an improved fluid atomizer. It is a further object to provide an atomizer having a variable volume whirl chamber in which the volume of the chamber is dependent upon the pressure of the supplied fluid. It is a further object to provide a more simplified, less costly atomizer having fewer components. Other objects are that this simplified device does not use air or steam to aid in atomization of the fuel oil and has no return flow.

This is accomplished by a vented plunger atomizer utilizing a variable volume whirl chamber which is achieved by movement of a piston within the whirl chamber cartridge. A fuel oil supply in an annulus between the cartridge and a burner barrel passes through uniquely spaced tangential oil ports in the wall of the whirl chamber cartridge and the oil swirls in the whirl chamber forming a vortex which exerts pressure on the piston. This compresses the spring to move the piston backward increasing the volume of the whirl chamber and at the same time uncovering additional oil ports. The chamber in which the spring rests is vented through the vent hole in the piston into the air core of the vortex thus maintaining a differential pressure across the piston so that as the supply oil pressure is increased, the piston moves further back in the whirl chamber. The orifice plate closes the front end of the whirl chamber and seals against the front face of the whirl chamber cartridge.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a sectional side view of the fuel atomizer assembly with fuel consumption at partial load;

FIG. 2 is a partial sectional view of the assembly along line 2 2 of FIG. 1; and

FIG. 3 is an arrangement of the tangential ports of FIGS. 1 and 2; and

FIG. 4 shows the axial location of the tangential ports of FIG. 3 on the same center line.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing and more particularly to FIG. I, there is shown a vented plunger atomizer 10 having all parts made of hardened stainless steel. A threaded cap nut 11 with a lip 12 and annulus 13 form the forward portion of atomizer 10. An orifice plate 14 having an orifice l5 normally of circular cross-section is inserted within and abutting a portion of the inside walls of cap nut 11. The opening that serves as orifice extends in diameter toward the rear of plate 14 and extends into a portion of a whirl chamber 16. The orifice plate 14 has grooved outer surfaces along its front and rear walls for respective registration with the cap nut 11 and a whirl chamber cartridge 21).

The whirl chamber cartridge is a substantially hollow cylindrical piece with a flange 25 at the forward end. The flange 25 has a lip 26 at its forward outer radial portion for registration with orifice plate 14. The forward inner diameter of cartridge 20 forms an opening of equal diameter to the opening in the rearward face of plate 14. Rearward of flange 25 in cartridge 21) are a plurality of tangential ports 30 for conducting oil from the outside of cartridge 20 into the whirl chamber 16.

A piston 31 often called a plunger is located inside the cartridge 20. The piston 31 is free to move within defined limits in an axial direction. The axial position of the piston 31 determines the volume of whirl chamber 16 and the number of tangential ports 30 free to supply fluid to the whirl chamber 16. A vent hole 32 tapered to a smaller cross-sectional area near chamber 16 extends the entire length of piston 31. A flange 33 forms a seat against a shoulder 34 of cartridge 20 for the piston 31 so as to provide a minimum size whirl chamber 16. This enables at least one tangential port 30 to be open at all times for permitting the flow of oil to the chamber 16. A rear projection 35 of piston 31 extends axially inside of cartridge 20. The rear cham' ber portion of chamber cartridge 20 has a larger annulus than the forward portion to permit movement of flange 33 within its confines.

The rear inner wall of cartridge 21) is threaded to mate with threads of a spring retainer 10 that seals the rearward end of cartridge 20. Retainer 40 can have a hex head 41 or other suitable shape for tightening the forward wall of a flanged piece 42 against the end of cartridge 20. In addition, a circular block 43 forming part of retainer 40 extends axially into the end of cartridge 20. A safety wire 46 is connected between hex head 41 and the cartridge 20.

A coil spring 50 is positioned between flange 33 and a flat surface 44 of retainer 410. The spring 51) provides a retaining force for positioning piston 31.

A burner barrel 60 encloses cartridge 20 in an axial direction. A radial spacing 61 is provided for the flow of oil to the tangential ports 30. The barrel 60 is threaded along the forward part of its outer wall for connecting to the threads of cap nut 11. The forward wall of burner barrel 60 abuts the outer radial groove of flange 25 so that the orifice plate 14 and the whirl chamber cartridge 20 are securely positioned.

Referring now to FIG. 2, there is shown a sectional view of the atomizer 10 along the line 2 2. The piston 31 is shown with tangential ports 30 located at four radial positions 90 apart. The ports 30 are all axially spaced from each other along cartridge 20.

FIGS. 3 and 4 show the pattern of the

tangential ports

30a, 30b, 30c and 30a. The ports overlap in the axial direction and follow the

sequence

30a, 3110, 30b and 30d. This provides a radial spacing in the whirl direction of at least l80 for subsequent ports. It additionally provides exactly 180 radial spacing for one-half of the adjacent holes in the axial direction. It has been found that such spacing gives superior performance to that found by sequentially spacing the ports 30 in rotational order. In addition, ports 30c and 30b are blanked after the first 341a port for improved performance at minimum rate.

In operation, at minimum loading, fluid enters whirl chamber 16 through the most forward of the ports 30a is accelerated to a high velocity and exits through the orifice plate 14 as a thin conical sheet and is converted to a fine spray. As the oil pressure is increased through the operation of a manually or automatically controlled valve (not shown), the vortex within chamber 16 exerts a greater pressure on piston 31 and forces it rearwardly in an axial direction against the restoring force of spring 50. At maximum load, all of the

ports

30a, 30b, 30c and 3d are open for transmitting fluid to an increased volume whirl chamber 16. The distance the spring is compressed is a function of the pressure exerted by the vortex within the whirl chamber. The pro jection 35 and the block 13 are so positioned that there is ample space provided to open all

tangential ports

30a, 30b, 30c and 30d prior to the projection 35 bottoming out against the block 13. The chamber housing spring 50 is vented through the center of the piston 31 to the vortex generated in whirl chamber 16. This insures a differential pressure across the piston 31 for compressing the spring 50.

It has therefore been shown a simplified atomizer for use in the combustion of oil in main propulsion boilers. The atomizer is of the non-return flow type and has a wide range capability. In addition, the atomizer utilizes a low pressure (350 psi) fuel supply system and does not require steam or air to augment atomization. There are no O-rings used for seals which gives the atomizer a longer lifetime and depending upon the location of the O-rings could hinder movable parts.

It will be understood that various changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the an within the principle and scope of the invention as expressed in the appended claims.

What is claimed is: 1. A whirl chamber cartridge adapted to be used in a fluid atomizer comprising:

a hollow substantially cylindrical member having a plurality of holes therethrough tangential to the circumference thereof adjacent to one end, said holes being located at one of four radial locations substantially apart, the spacing of said holes being such that a plurality thereof overlap in the axial direction with others of said holes, such overlap being at a radial spacing of at least in the whirl direction within the cartridge.

2. A whirl chamber cartridge according to claim 1 further comprising:

a flange forward of said holes adapted to register with the fluid atomizer;

a shoulder located on the inner wall of the cartridge at a location rearward of said holes; and

screw threads located at the rear inner wall of the cartridge.

3. A fluid atomizer comprising:

an orifice plate forming an orifice and a portion of a whirl chamber;

a whirl chamber cartridge in abutting relationship with said orifice plate forming a portion of said whirl chamber for selectively passing a fluid thereto, said cartridge being a hollow, substantially cylindrical member including a plurality of holes therethrough adjacent to one end thereof tangential to said whirl chamber and located at one of four radial positions substantially 90 apart, the spacing of said holes being such that a plurality thereof overlap in the axial direction with others of said holes, such overlap being at a radial spacing of at least 180 in the whirl direction within the cartridge;

slideable means insertable in said whirl chamber cartridge and forming a rearward boundary of said whirl chamber for determining the volume of fluid conducted thereto by selectively blocking said holes, and having a vent hole communicating between said whirl chamber and a rearward axial portion of said whirl chamber cartridge; and

restraining and restoring means axially abutting said slidable means for biasing said slideable means toward said orifice plate.

4. A fluid atomizer according to claim 3 wherein said slidable means further comprises:

a piston having a flange for limiting travel in the forward axial direction and a projection for limiting travel in the rearward axial direction.

5. A fluid atomizer according to claim 4 wherein said restraining and restoring means further comprises:

a spring retainer secured to the end of said whirl chamber cartridge having a block extending forwardly into said cylindrical member in an axial direction; and a spring having one end surrounding said projection and the other end surrounding said block.

6. A fluid atomizer according to claim 5 wherein said whirl chamber cartridge further comprises:

a flange forward of said tangential ports abutting and registering with said orifice plate;

a shoulder located on the inner wall of said cartridge at a location rearward of said tangential ports; and screw threads located at the rear inner wall of said cartridge for connecting with said spring retainer.

7. A fluid atomizer according to claim 6 further comprising:

a cap nut having inner screw threads abutting the forward and outer radial surfaces of said orifice plate and the outer radial surface of said whirl chamber cartridge flange; and

a burner barrel abutting said whirl chamber cartridge flange, extending at a predetermined radial distance from the remainder of said whirl chamber cartridge and having outer screw threads at the forward end for connecting with said cap nut.

8. A fluid atomizer comprising:

an orifice plate forming an orifice and a portion of a whirl chamber;

a whirl chamber cartridge being a hollow, substantially cylindrical member including a plurality of holes therethrough adjacent to one end thereof tangential to said whirl chamber and located at one of four radial positions substantially apart, the spacing of said holes being such that a plurality thereof overlap in the axial direction with others of said holes, such overlap being at a radial spacing of at least in the whirl direction within the cartridge for selectively passing a fluid to said whirl chamber, said cartridge having a flange forward of said tangential holes abutting and registering with said orifice plate and forming a portion of said whirl chamber, a shoulder located on the inner wall of said cartridge at a location rearward of said tangential holes, and screw threads located at the rear inner wall of said cartridge;

a piston slideable in said whirl chamber cartridge and forming a rearward boundary of said whirl chamber for determining the volume of fluid conducted thereto by selectively blocking said holes, and having a vent hole communicating between said whirl chamber and a rearward axial portion of said whirl chamber cartridge, a flange for limiting travel in the forward axial direction and a projection for limiting travel in the rearward axial direction;

restraining and restoring means including a spring retainer secured to said screw threads having a block extending forwardly into said cylindrical member, and a spring having one end surrounding said projection and the other end surrounding said block for biasing said piston toward said orifice plate;

9. A whirl chamber cartridge adapted to be used in a fluid atomizer comprising:

a hollow, substantially cylindrical member having a plurality of holes therethrough tangential to the circumference thereof adjacent to one end, said holes being located at one of four radial locations substantially 90 apart, the spacing of said holes being such that a plurality thereof overlap in the axial direction with others of said holes, such overlap being at a radial spacing of at least 180 in the whirl direction within the cartridge, and having a flange forward of said holes adapted to register with the fluid atomizer, a shoulder located on the inner wall of the cartridge at a location rearward of said holes and screw threads located at the rear inner wall of the cartridge.

Claims

1. A whirl chamber cartridge adapted to be used in a fluid atomizer comprising: a hollow substantially cylindrical member having a plurality of holes therethrough tangential to the circumference thereof adjacent to one end, said holes being located at one of four radial locations substantially 90* apart, the spacing of said holes being such that a plurality thereof overlap in the axial direction with others of said holes, such overlap being at a radial spacing of at least 180* in the whirl direction within the cartridge.

2. A whirl chamber cartridge according to claim 1 further comprising: a flange forward of said holes adapted to register with the fluid atomizer; a shoulder located on the inner wall of the cartridge at a location rearward of said holes; and screw threads located at the rear inner wall of the cartridge.

3. A fluid atomizer comprising: an orifice plate forming an orifice and a portion of a whirl chamber; a whirl chamber cartridge in abutting relationship with said orifice plate forming a portion of said whirl chamber for selectively passing a fluid thereto, said cartridge being a hollow, substantially cylindrical member including a plurality of holes therethrough adjacent to one end thereof tangential to said whirl chamber and located at one of four radial positions substantially 90* apart, the spacing of said holes being such that a plurality thereof overlap in the axial direction with others of said holes, such overlap being at a radial spacing of at least 180* in the whirl direction within the cartridge; slideable means insertable in said whirl chamber cartridge and forming a rearward boundary of said whirl chamber for determining the volume of fluid conducted thereto by selectively blocking said holes, and having a vent hole communicating between said whirl chamber and a rearward axial portion of said whirl chamber cartridge; and restraining and restoring means axially abutting said slidable means for biasing said slideable means toward said orifice plate.

4. A fluid atomizer according to claim 3 wherein said slidable means further comprises: a piston having a flange for limiting travel in the forward axial direction and a projection for limiting travel in the rearward axial direction.

5. A fluid atomizer according to claim 4 wherein said restraining and restoring means further comprises: a spring retainer secured to the end of said whirl chamber cartridge having a block extending forwardly Into said cylindrical member in an axial direction; and a spring having one end surrounding said projection and the other end surrounding said block.

6. A fluid atomizer according to claim 5 wherein said whirl chamber cartridge further comprises: a flange forward of said tangential ports abutting and registering with said orifice plate; a shoulder located on the inner wall of said cartridge at a location rearward of said tangential ports; and screw threads located at the rear inner wall of said cartridge for connecting with said spring retainer.

7. A fluid atomizer according to claim 6 further comprising: a cap nut having inner screw threads abutting the forward and outer radial surfaces of said orifice plate and the outer radial surface of said whirl chamber cartridge flange; and a burner barrel abutting said whirl chamber cartridge flange, extending at a predetermined radial distance from the remainder of said whirl chamber cartridge and having outer screw threads at the forward end for connecting with said cap nut.

8. A fluid atomizer comprising: an orifice plate forming an orifice and a portion of a whirl chamber; a whirl chamber cartridge being a hollow, substantially cylindrical member including a plurality of holes therethrough adjacent to one end thereof tangential to said whirl chamber and located at one of four radial positions substantially 90* apart, the spacing of said holes being such that a plurality thereof overlap in the axial direction with others of said holes, such overlap being at a radial spacing of at least 180* in the whirl direction within the cartridge for selectively passing a fluid to said whirl chamber, said cartridge having a flange forward of said tangential holes abutting and registering with said orifice plate and forming a portion of said whirl chamber, a shoulder located on the inner wall of said cartridge at a location rearward of said tangential holes, and screw threads located at the rear inner wall of said cartridge; a piston slideable in said whirl chamber cartridge and forming a rearward boundary of said whirl chamber for determining the volume of fluid conducted thereto by selectively blocking said holes, and having a vent hole communicating between said whirl chamber and a rearward axial portion of said whirl chamber cartridge, a flange for limiting travel in the forward axial direction and a projection for limiting travel in the rearward axial direction; restraining and restoring means including a spring retainer secured to said screw threads having a block extending forwardly into said cylindrical member, and a spring having one end surrounding said projection and the other end surrounding said block for biasing said piston toward said orifice plate; a cap nut having inner screw threads abutting the forward and outer radial surfaces of said orifice plate and the outer radial surface of said whirl chamber cartridge flange; and a burner barrel abutting said whirl chamber cartridge flange, extending at a predetermined radial distance from the remainder of said whirl chamber cartridge and having outer screw threads at the forward end for connecting with said cap nut.

9. A whirl chamber cartridge adapted to be used in a fluid atomizer comprising: a hollow, substantially cylindrical member having a plurality of holes therethrough tangential to the circumference thereof adjacent to one end, said holes being located at one of four radial locations substantially 90* apart, the spacing of said holes being such that a plurality thereof overlap in the axial direction with others of said holes, such overlap being at a radial spacing of at least 180* in the whirl direction within the cartridge, and having a flange forward of said holes adapted to register with the fluid atomizer, a shoulder located on the inner wall of the cartridge at a location rearward of said holes and screw threads located at the rear inner wall of the cartridge.