US3303892A - Fuel atomization device in diesel pile driver - Google Patents

Description

1967 SHOJIRO NISHIMURA ETAL 3,303,392

FUEL ATOMIZATION DEVICE IN DIESEL FILE DRIVER Filed June 23, 1964 PRIOR 4/"? T PR/OR ART 2O '2 I; g5 g 18 I ,1 p I4 INVENTOR5 SHOJIRO NI SHIMURA, MASAO,

ISHIZAKI, AND HIROTOSHI BABA.

ATTO Y.

United States Patent 3,393,892 FUEL ATOMIZATION DEVICE IN DIESEL PHE DRIVER Shojiro Nishimura, Ashiya-shi, Masao Ishizaki, Nada-kn, Kobe, and Hirotoshi Babe, Higashi-Nada-ku, Kobe, Japan, assignors to Kobe Steel Works, Ltd, Kobe, Japan Filed June 23, 1964, Ser. No. 377,355 Clairns prior-i application Japan, June 24, 1963, 38/4633!) 2 Claims. (Cl. 173-133) The present invention relates to a fuel atomization device for use in a diesel pile driver and more particularly relates to a fuel atomization device for a diesel pile driver of the type in which the impact portions of the hammer and anvil of the diesel pile driver are uniquely designed so that the fuel within the pile hammer is perfectly atomized and thereby the driving efficiency of such pile driver is greatly improved and, also, instability in the driving of the hammer, which has been one of the most serious drawbacks associated with the prior art diesel pile drivers, is eliminated.

In the prior art diesel pile driver as shown in FIGS. 1 and 2, hammer 1 is generally raised by a suitable actuating means and when the hammer has reached a predetermined height the hammer automatically drops.

As hammer 1 drops, it actuates cam 3 of fuel pump 2 so as to spray a predetermined amount of fuel onto anvil 4 and at the same time the air below air supply-exhaust bores 5 is entrapped by oncoming piston ring 6 and such air is further highly compressed by the dropping hammer 1. Thereafter, when hammer head 7 strikes against anvil 4 the sprayed fuel is atomized and distributed throughout the compressed air maintained at a high temperature and a high pressure and instantaneously and explosively burns. The high pressure caused by the collision between the hammer and anvil as well as the explosive combustion of the fuel imparts driving energy to the pile to be driven and simultaneously, the remainder of the combustion gas energy lifts the hammer to its drop position again. By repeating this diesel cycle a pile can be continuously driven into the ground until it reaches a desired depth.

When the pile is driven by a pile driver of the prior art in the manner set forth above, if the pile is being driven in against relatively little resistance, because of, for instance, comparatively soft ground, a pile of comparatively small diameter or a comparatively light pile, the distance the pile moves each time the hammer strikes is great and the impact of hammer or anvil does not fully atomize the fuel. This results in incomplete combustion. In this case, the return stroke of the hammer after its collision with anvil 4 is shortened and with a short hammer stroke, cyclic fuel explosions fail to take place and a steady driving operation by the hammer is not ensured. Because of this drawback a specific actuating means has to be employed in the prior art diesel pile driver to help lift hammer 1 up after each blow by the hammer; this lowers the operative efficiency of the pile driver to a serious extent.

If one watches a conventional diesel pile driver while it is driving a pile into soft ground, he will note that anvil 4 sinks into the ground together with the pile before falling hammer It strikes against anvil 4 again, the result hein a decrease in relative speed between the hammer and anvil. This decrease in relative speed between the hammer and anvil correspondingly reduces the force available for compressing the fuel oil between the hammer and anvil, and accordingly, the fuel is imperfectly atomized and the particles of fuel do not become sufficiently fine. Furthermore, because of the insufl'icient impact force, the atomized fuel is not evenly distributed throughout the compressed air. The combination of the above drawbacks leads to imperfect ignition of the fuel.

Patented Feb. 14, 1967 ice Since the relative speed between the hammer and anvil depends upon the size of the hammer in relation to the piles to be driven by the hammer and on the condition of the ground where the piles are driven, in order to improve the operative efiiciency of a conventional driver, it seemed evident that the hammer and anvil would have to be improved.

For example, the shape of the combustion chamber and the shapes of the impact surfaces of the hammer and anvil might be improved.

With the above facts in mind, the shapes of the impact surfaces of the hammer and anvil were changed and the present invention was developed to provide an efficient diesel pile driver with an atomization device which atomizes the fuel perfectly.

The present invention provides an improved atomization device in which the impact surfaces (contact surfaces) of the hammer and anvil are designed to have unique configurations, that is, the top surface of the anvil is provided with a centrically disposed convexly shaped projection and an annular recess surrounding said projection whilst the bottom surface of the hammer is pro vided with a centrically disposed recess and an annular ridge, said center recess and annular ridge being opposed and complementary to said center convexly shaped projection and annular recess of the anvil respectively, whereby the fuel on the anvil may be accumulated in the vicinity of the inner wall of the cylinder.

Furthermore, according to the present invention, since the fuel is accumulated within the annular recess on the top of the anvil, the fuel is compressed in the vicinity of the inner wall of the cylinder or the combustion chamber, and accordingly, fuel spraying pressure in the path along which the fuel is outwardly sprayed is not decreased, resulting in highly efiicient atomization of the fuel.

In the prior art fuel atomization device as shown in FIGS. 1 and 2, the Opposing impact surfaces of the hammer and anvil are semicircular in shape. In contrast, the specially shaped impact surfaces of the hammer and anvil of the present invention make the hammer-anvil combination of the present invention superior to the prior art ram and anvil.

Having briefly described the invention, a more detailed description is made below by reference to typical embodiments of the invention as illustrated in the drawings.

In the drawings:

FIG. 1 is a vertical cross-sectional view of a prior art diesel pile driver showing the inner arrangement thereof;

FIG. 2 is a vertical cross-sectional view of the fuel atomization device provided within said pile driver of FIG. 1;

FIG. 3 is a vertical cross-sectional view of a fuel atomization device according to the present invention;

FIG. 4 is a schematically view showing the manner in which the fuel is atomized in said atomization device of FIG. 3; and

FIG. 5 is a vertical cross-sectional view of a modified atomization device of the present invention.

Reference will now be made to the preferred embodiment of the present invention shown in FIGS. 3 and 4. In this embodiment hammer 10 is disposed within cylinder 11 for reciprocal up and down movement therein. Anvil 12 fits in at the lower end portion of cylinder 11 for frictional movement with respect to the cylinder for a predetermined distance. Hammer 10 is provided with an integrally formed downwardly projecting foot portion 13 at its bottom end and foot portiton 13 has a diameter d which is smaller than the diameter D of the hammer itself. The top end of anvil 12 which is opposed to the bottom end of hammer 10 or the foot portion 13 is formed with a dish-like recess 14 of diameter d which is the same 3 as the diameter d of foot portiton 13. The bottom surface of foot portion 13 and the bottom surface of dishlike recess 14 form the impact surfaces of hammer and anvil 12, respectively.

Dish-like recess 14 is provided with a projection 15 having a suitable height at its center and a valley-shaped annular recess 16 surrounding center projection 15. The top surface of projection 15 is connected with the bottom surface of annular recess 16. The cross-sectional shape of projection 15 is preferably of a gentle curve as seen in FIG. 3, but alternatively the cross-sectional shape of the projection may be angular as seen in FIG. 5.

On the other hand, the bottom surface of hammer foot portion 13 is provided with a circular concave groove 17 in its center and said concave groove 17 has a shape complementary to the shape of projection 15 at anvil recess 14. Annular ridge 18 is provided surrounding concave 17 and ridge 18 has a shape complementary to the shape of annular recess 16.

Therefore, when the bottom surface of hammer foot portion 13 comes into contact with the bottom surface of anvil recess 14, a contact surface comprised of centrally projecting surface 19 and annular recess 20 surrounding projecting surface 19 is formed, as seen in FIG. 4. In the atomization device as described above, the fuel which has been sprayed from the fuel pump nozzle into the cylinder falls onto anvil 12, enters dish-like recess 14 and finally accumulates within annular recess 16. As hammer 10, which has been previously raised, drops, foot portion 13 of hammer 10 enters dish-like recess 14 of anvil 12 to gradually compress the air and fuel there and when the hammer and anvil collide with each other the fuel is caused to be atomized and scattered in all directions.

The manner in which the fuel is atomized and scattered in all directions is shown in FIG 4. If both the contact surfaces of the hammer and anvil are formed as complemental spherical shapes, the fuel accumulates itself at the center of the top of the anvil (see FIG. 2), and accordingly, in order that the fuel be atomized and scattered in all directions in such a prior art device, the fuel requires a path L as shown in FIG. 2. However, if the recess 16 where the fuel accumulates itself is formed as an annular shape, the fuel is scattered by way of a path 1 (FIG. 4) which is substantially shorter than the path L in FIG. 2.

In order that the fuel scatters into the cylinder, the fuel must pass along the path L or I but, at this time, since viscosity of the fuel substantially resists such passing of the fuel the shorter the path, the lesser the resistance by the fuel viscosity, and accordingly, with the shorter path I, there will be little loss of the pressure in scattering the fuel and the atomization of the fuel can be perfectly performed. This is one important advantage to be obtained by the present invention.

When the recess 16 which is provided for accumulating the fuel on the top of the anvil 12 is formed with an annular shape, the surface 18 of annular ridge 18 has come to contact the fuel surface within the annular recess 16 of anvil 12 first during the downward stroke of hammer 10. The air entrapped between the hammer and anvil inwardly of the contacting circle defined by surface 18 the fuel in and recess 16 is sealed therein and compressed in situ, and accordingly, the pressure exerted by the compressed air serves to scatter the fuel outwardly. As a resuit, the fuel is scattered radially and outwardly with a substantially great force, thereby ensuring perfect atomization'of the fuel. The atomized fine particles of fuel are evenly distributed into the cylinder and positively ignited. This is another advantage of the present invention, which can not be expected in the prior art atomization device of FIGS. 1 and 2. The shape of the bottom end surface of the hammer and that of the upper end surface of the anvil are designed so they may not be completely complementary to each other, but leave a slight clearance between the upper surface of the projection 15 and the bottom surface of the concave 17.

As is evident from the foregoing, the atomization device by the present invention can effect perfect atomization, thereby eliminating the defect such as poor driving efficiency due to insufficient upward movement of the hammer which is caused by imperfect atomizatiton of the fuel. The diesel pile driver incorporating the novel atomization device can not only be expected to perform efficiently on soft grounds, but also the hammer can be continuously driven with a great horse-power through the improved atomizing efiiciency, and in addition, such a hammer can provide a maximum driving force obtainable with a fixed amount of fuel. Thus, the diesel pile driver incorporating the novel atomization device by the present invention has a great utility.

It should be understood that the present invention is not limited to the details of the foregoing descriptions and illustrations of the typical embodients of the invention, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

What is claimed is:

1. A fuel atomization device and diesel pile driver, comprising a cylinder, a hammer disposed within said cylinder for reciprocal movement and having an impact surface at the lower end thereof, and an anvil fit in said cylinder at the lower end for a limited frictional movement and having an impact surface at the upper end thereof, said upper end impact surface of the anvil being opposed to said impact surface of the hammer and adapted to accumulate fuel thereon so that when said hammer drops and strikes against said anvil said fuel is atomized, said lower end impact surface of the hammer being provided with a centrally positioned concave circular groove and an annular ridge surrounding said groove, said upper end impact surface of the anvil being provided with a centrally positioned convexly shaped projection and an annular recess surrounding said projection whereby the fuel may be accumulated in the vicinity of the inner wall of said cylinder.

2. A fuel atomization device and diesel pile driver, comprising a cylinder, a hammer disposed within said cylinder for reciprocal'movement and having an impact surface at the lower end thereof, and an anvil fit in said cylinder at the lower end for a limited frictional movement and having an impact surface at the upper end thereof, said upper end impact surface of the anvil being opposed to said impact surface of the hammer and adapted to accumulate fuel thereon so that when said hammer drops and strikes against said anvil said fuel is atomized, said lower end impact surface of the hammer being provided with a centrally disposed recess having a square cross-section and an annular ridge surrounding said recess, said upper end impact surface of the anvil being provided with a centrally disposed projection having a square cross-section and an annular recess surrounding said projection whereby the fuel may be accumulated in the vicinity of the inner wall of said cylinder.

References Cited by the Examiner UNITED STATES PATENTS 2,093,634 9/1937 Cordes 173133 2,208,730 7/1940 Pfeiffer 173-133 2,633,832 4/1953 Sparlin 173133 2,740,385 4/1956 Hoage 173135 FRED C. MATTERN, JR., Primary Examiner. L. P. KESSLER, Assistant Examiner.

Claims (1)

1. A FUEL ATOMIZATION DEVICE AND DIESEL PILE DRIVER, COMPRISING A CYLINDER, A HAMMER DISPOSED WITHIN SAID CYLINDER FOR RECIPROCAL MOVEMENT AND HAVING AN IMPACT SURFACE AT THE LOWER END THEREOF, AND AN ANVIL FIT IN SAID CYLINDER AT THE LOWER END FOR A LIMITED FRICTIONAL MOVEMENT AND HAVING AN IMPACT SURFACE AT THE UPPER END THEREOF, SAID UPPER END IMPACT SURFACE OF THE ANVIL BEING OPPOSED TO SAID IMPACT SURFACE OF THE HAMMER AND ADAPTED TO ACCUMULATE FUEL THEREON SO THAT WHEN SAID HAMMER DROPS AND STRIKES AGAINST SAID ANVIL SAID FUEL IS ATOMIZED, SAID LOWER END IMPACT SURFACE OF THE HAMMER BEING PROVIDED WITH A CENTRALLY POSITIONED CONCAVE CIRCULAR GROOVE AND AN ANNULAR RIDGE SURROUNDING SAID GROOVE, SAID UPPER END IMPACT SURFACE OF THE ANVIL BEING PROVIDED WITH A CENTRALLY POSITIONED CONVEXLY SHAPED PROJECTION AND AN ANNULAR RECESS SURROUNDING SAID PROJECTION WHEREBY THE FUEL MAY BE ACCUMULATED IN THE VICINITY OF THE INNER WALL OF SAID CYLINDER.

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