CA1036499A

CA1036499A - Pile-driving ram

Info

Publication number: CA1036499A
Application number: CA241,384A
Authority: CA
Inventors: Hans G. Schnell
Original assignee: Van Kooten BV
Current assignee: Van Kooten BV
Priority date: 1974-12-10
Filing date: 1975-12-09
Publication date: 1978-08-15
Also published as: AU8728475A; JPS5186205A; BE836305A; DE2555340A1; FR2294276A1; GB1503995A; NL7416085A; DE2555340B2; FR2294276B3

Abstract

Abstract of the Disclosure In a pile-driving ram in accordance with the invention a fuel injector sprays fuel at two relatively spaced areas onto the impact surfaces of piston or striker.
When the piston strikes on the striker the fuel, which is already well divided about the impact surface of the striker, is atomized away from the impact surface of the striker in a direction towards a compression space surrounding the striker so that it is brought into an intensive contact with the air of the compression space in order to produce ignition of the fuel-air mixture.

Description

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M Kon/HH,8 ~1 ,, ~(~36~9 The invention relates to a pile-driviny ram com-prising at least one combustion cylinder, a striker extending into the combustion cylinder, a piston arranyed ln the cornbustion cylinder and a fuel injector for suppl~iny fuel bet~Jeen the impact surfaces of the piston and the striker.
Such a pile-driving ram is known from U.S. Patent ~! Specification 3,747,693. It is disclosed herein that the fuel ; -- is sprayed at one and the same area to the impact surface of the striker in one direction, it being expected that the ;` I
fuel will flow out across the whole or substantially the whole impact surface. At the stroke of the piston on the striker the fuel is atomized away from the impact surface of the striker ` ! , n a direction towards a compression space surrounding the striker so that it is mixed with the air of the compression space in order to produce ignition of the fuel-air mixture.
¦ The time required for the fuel to flow out acros~ the impact surface is considerably longer than the time interval between ¦ the injection and the stroke of the piston so that the spread of the fuel as expected hardly occurs or is at least not achieved perfectly. Particularly if the height of the piston movement is small in the event of slight ground resistance, the impact atomization is not sufficient to produce intimate contact between air and fuel. As a result the fuel-air mixture in the known ram does not ignite satisfactorily or is not ignited at all.
! 25 The invention has for its object to provide a .

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~ pile-driving ram operating independently of the grsund resistance.
; According to the present invention there is provided a pile-driving ram comprising at least one combustion cylinder, a striker extending in~o the combustion cylinder, a piston arranged in the combustion cylinder and fuel injector means for supplying uel between the impact surfaces of the piston and the striker, said uel injector means being adapted to spray fuel onto the impact surface of the striker at least at three rela-tively spaced areas.
With this arrangement, the fuel atomization is improved so that it is more intensively mixed with air and will ignite with greater certainty.
The fuel injector preferably comprises at least three nozzles dis-tributed along the circumference of the combustion cylinder. This provides a further improvement of the fuel distribution along the circumference of the compression space.
In order to ensure that all areas of the impact surface struck by fuel will receive equal quantities of fuel, the fuel injector may com-prise at least three fuel pumps or at least one fuel pump with at least three pump cylinders.
Dutch patent application 7215218 describes a pump having several bores in order to choose a pump output at will. ~nly one of a plurality of pumps is used, whilst one pump is employed for lubricating oil and the other for fuel.
German Patent Application 1,936,529, laid up for public inspection, relates to a direct injection in the air (nebulation). Fuel is not sprayed at different areas onto an impact surface. The same applies to Dutch Patent Specification 46,276.
In German Patent Publication 1,058,944 ~see the preamble, column 1, lines 31 to 40) it is disclosed that in the injection of two kinds of fuel the starting fuel is injected by a second pump. In this literature it is furthermore stated that neither the two kinds of ~uel are injected ~ - 3 -~.~36~99 at different areas onto an impact surface, nor that different fuel injection nozzles are used and nor that the two different fuels are simultaneously injected.
Embodiments of the invention will be explained in the following description with reference to drawings in which:
Figure 1 illustrates a survey of the pile-driving operation by means of a ~ile-driver equipped with a ram in accordance with the in~ention;
Figure 2 is an enlarged vertical sectional view of a ram as shown in Figure 1, Figure 3 is an enlarged view of a preferred embodiment of a detail ; III in Figure 2 in a different position, Figure 4 is an enlarged sectional view taken on the line IV-IV
in Figure 2, Figure 5 is a sectional view corresponding with Figure 4 with a diagram relating to a different embodiment of the ram in accordance with the invention, Figure 6 is a diagram relating to the fuel injector for ~he ram of Figure 5, and Figure 7 is a control-diagram for a ram as shown in Figure 5.
By means of a floating derrick 24 a pile-driver 27 is arranged on a pile 21 to be driven into the soil 23 beneath the water 22. Said pile-driver 27 comprises a guide frame 35 comprising a socket 25 surrounding the pile 21, and two guide :

~,:~ - 4 -1()3~ 99 l stays 29 secured thereto. The pile-driver 27 furthermore comprises a ram 8 guided by means of guide members 37 alony the stays 29 and formed by a Diesel ram and a cap 31 beariny . on the pile 21.

: ~ 5 Figure 2 shows that the ram 8 cimprises a combustion : cylinder 3, a piston 1 operating as a hammer -therein and a ~ striker 2 bearing on the pile cap 31 and extending into the ; . combustion cylinder 3. The combustion cylinder 3 holds a tank 28 ~- and has ports 26 for the air inlet and for the exhaust gases and at least one fuel injection nozzle 30 of a fuel injector 6.
.,. ~,j ~ :, . The piston 1 is sealed with respect to the combustion ;

cylinder 3 by means of piston rings 19 and has a piston head 2n, surrounded by an annular compression chamber 18. A conical impact surface 4 of tbe striker 2 matches an engaging impact ; 15 surface 5 of the piston 1.
From Figure 4 it will be apparent that fuel is sprayed I at a plurality of areas distrlbuted across the circumference of the impact surface 4 onto said surface, for example, by three jets 15 from the nozzle 30 so that three fuel zones 13 20 are formed. When the piston 1 strikes the striker 2, the fuel is satisfactorily atomized and fans out like a curtain 12 in the direction 17 away from the impact surface 4 into the lower part 16 of a precombustion chamber 10 of the compression : chamber 18 since a shallow, annular recess 11 adjacent the impact surface 4 is provided in the striker 2. The fuel is then ignited in the precombustion chamber 10 and the combustion takes place slightly later mainly in the main combustlon . .. ..

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chamber 32. This delay of the combustion process provides a considerable improvement in the strikiny effect of the ram 8.
~l Owing to the finely divided particles the satisfactoril~
atomized fuel ignites readily, even with a small striking path of the piston 1, but 0~7ing to lac~ of air in the precornbustion chamber 10 the combustion i5 i~rformed slowl~.
Referring to Figurs 1 to 4 the ~uel injector 6 com-prises only one pump with one nozzle 30, but the fuel injector 6 , shown in Figures 5 to 7 comprises two diametrically opposite nozzles 30a and two diametrically opposite nozzles 30b communicating with a pump 7a for a basic fuel 38 formed by Diesel oil and a pump 7b for a substance 39 affecting the combustion velocity respectively. The pumps 7a and 7b have, ., I
for each nozzle, a separate pump cylinder 9, the pump volume of which is adjusted by an adjustable stop 33a and 33b respectively. The positions of the stops 33a and 33b are I determined by means of a control-member 41a and 41b respectively, `¦ which regulates the supply and drainage of liquid 42 through a control-slide 43a, 43b for a hydraulic cylinder 44a and 44b respectively, as shown in the control-diagram of Figure 7.
The supply of fuel to the ram 8 results at each ; ! combustion in a stroke on the pile 21. The result of the stroke is measured on the pile 21 by means of a feeler 45.
This feeler 45 may be formed by an optical meter which measures l 25 the axial displacement 51 of the pile 21 resulting from each stroke. The measured value 48 may be compared as the result of a stroke in a comparator 46 with a datum value 49 prescribed .

i .. . ... -, -1~J36~99 by a proyramme 47, after which the difference siynal 50 energizes the control-members 41a and 41b. The diference signals SO bring about a displacement of the stops 33a and 33b. The sense and the value of the displacements are programmed in the control-member 41.
The substance 39, for example petrol, is supplied ~l as an accelerating agent to an extent proportional to the tendency of the combustion to slow down. This occurs in . accordance with a decreasing ground resistance. ~hen the feeler 45 measures a large axial displacement 51, which signifies a slight ground resistance, the pump 7b will supply a large quantity of combustion-accelerating substance 39 to the ram 8.
If it is previously known that the ground resistance will be heavy~, the tank 40 will contain, instead of petrol, a substance 39, for example, benzene, decelerating the combustion I velocity, which substance will then be supplied to the ram 8 i by the pump 7b according to a different programme/proportionally ; to the increase in ground resistance.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A pile-driving ram comprising at least one combustion cylinder, a striker extending into the combustion cylinder, a piston arranged in the combustion cylinder and fuel injector means for supplying fuel between the impact surfaces of the piston and the striker, said fuel injector means being adapted to spray fuel onto the impact surface of the striker at least at three relatively spaced areas.

2. A pile-driving ram as claimed in claim 1, wherein the fuel injec-tor means comprises at least three nozzles spaced apart along the circum-ference of the combustion cylinder.

3. A pile-driving ram as claimed in claim 1, wherein the fuel injec-tor means comprises at least three fuel pumps.

4. A pile-driving ram as claimed in claim 1, wherein the fuel in-jector means comprises at least one fuel pump with at least three pump cylinders.