Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Seismic pulse generator for a Barlow.
The present invention relate to a seismic pulse generator for
producing seismic pulses in Berlioz.
Most of the present-day methods and device; for generating such
seismic pulses are based on the use of explosive charges, pus
electric vibrators, electric sparks and similar means which pro-
dupe a seismic signal in a Barlow usually filled with water.
The S waves of thus generated signals do not pass through fluid
media and therefore such prior art methods are not suitable for
S-wave generation.
Barlow clamped devices which are able to produce both P- and
S-waves are generally based on a mechanical impact. The prior
art devices are either manually activated by means of cables or
rods or electrically activated by means of solenoids and magnets.
However, both types are relatively bulky and require relatively
large Barlow diameters. They are also relatively weak which in
turn means that a relatively high density of Berlioz is no-
squired. These aspects amount to the fact that the prior art
equipment is uneconomical for use in preliminary geological
surveys.
An object of the present invention is to provide a device which
is capable of producing both P- and S-waves at a desired depth
in a hole drilled in rock, soil, concrete or similar media.
A further object of the invention is to eliminate the drawbacks
occurring when the device is controlled by means of cables, rods
and the like from the ground, said drawbacks increasing along
with the depth of a Barlow.
An object is also to provide a device capable of producing just
a single blow each time the device is activated.
A still further object of the invention is to provide when
necessary a pulse similar to the preceding one in a manner that
pulses can be repeated continuously.
A still further object of -the invention is to ensure direct
transmission of a produced pulse from the device to the walls
of a Barlow by using a clamp~r,g element that LO firmly attach-
able -to the Barlow walls.
An object of the invention is also to provide a pulse that is
considerably more effective than -those produced by manually or
electrically powered devices.
The invention can also be applied in small-size Berlioz, e.g.
in holes whose diameter is 56 mm which is a standard Barlow
size in geological surveys at least in Europe.
A still further object of the invention is to provide a pulse
either uphold or Donnelly, this feature being very important in
S-wave analysis.
A still further object of the invention is to provide a device
for detecting and transmitting about the blow moment up to the
ground.
In addition, the device of the invention is lightweight and thus
readily transportable.
A final object of the invention is to provide a device capable of
preventing the water in a Barlow from penetrating into the de-
vice which would considerably cut down the power of a blow.
The above objects are accomplished by means of a seismic pulse
generator according to the invention, comprising an elongated
tubular unit insertable in a Barlow and consisting of a hammer
element and clamping element, said hemmer element comprising a
hammer for hitting an anvil and said damping element comprising
at least one locking or clamping means extending hydraulically
from the wall of said device and serving to clamp the device in
a Barlow at a desired level, said device being characterized
I
in that said hammer element is provided with a double-actlon
hydraulic piston whose rod has at its free end a locking bell
for locking itself during the piston stroke in the clamping pin
of a spring-loaded hammer and towards the end of the piston
return stroke disengages its grip from said clamping pin.
In a preferred embodiment of the invention, the clamping element
or body is provided with a wedge means molted on a hydraulically
displaceable piston and having its wedge surfaces actively
engaged with the wedge surfaces of said locking or expander
plate whereby, when said wedge means is displaced in the long-
i~usinal direction of said clamping body, the spring-loaded
expander plate moves radially outwards from the clamping part
body.
Other characteristics of the invention are set forth in the
annexed claims 3-7~
The invention will now be described in more detail with reference
made to the accompanying drawings, in which:
fig. 1 shows one gable of a device of the invention,
fig. 2 is a side view of the gable shown in fig. 1,
fig. 3 is a section along the line III-III in fig. 1,
fig. 4 is a section along the line IV-IV in fig. 2,
fig. 5 shows the central part of a device of the invention,
fig. 6 is a section along the lineVI-VI in fig. 5,
fig. 7 shows the other gable of a device of the invention,
fig. 8 shows a control cable coupling element for a device of the
invention,
it
fig. 9 is a section along the line IX-IX in fig. 8,
igs. 10-13 show in a larger scale a detail about setting up and
triggering the hammer, and
fig. 14 shows a combination ox figs. 1, 5 and 7 of a device of
the invention.
First explained is the design of a device of the invention. A
device of the invention is an elongated cylindrical element or
body, comprising two connected part or bodies, namely a clamping
part body 16 and a hammer part body 27. The free end of said
clamping part body is fitted with an end cap 8 provided with a
waterproof electric connector 7 for a shock micro switch 9 focal-
Ed in said end cap. End cap 8 is sealed against clamping part body
16 by means of seals 10 compressed against the body by means of
its fastening bolt OWE Fastening bolt 11 is provided with a
through-passage which joins a hydraulic fluid supply passage 2
in said end cap. End cap 8 is further provided with another pass-
age 1 for hydraulic fluid, said passages in turn being in come
monkeyshine with respective passages made in body 16. In end cap 8,
the terminations of passages 1 and 2 have seals 22~
End cap 8 of the above-described device is fitted with a control
cable connection element 4, provided with a switch means 5 which
is intended for electric connector 7 and from which an electric
lead is passed up to the ground along a combined instrument cable
3. End cap 8 is shown in cross-section in fig. 9 and it is also
provided with hydraulic circuit passages 1 and 2 as well as with
a fastening bolt 6 for connection element 4. At this stage we
wish to point out that this connection element 4 can be alter-
natively mounted on the other end of the device.
Clamping part body 16 is provided with a cylinder space contain
in a reciprocating piston 12 and its rod 13 which extends throw
ugh a securing bolt 15 fitted sealing cap 14 from said cylinder
space to a slide space adjacent thereto. This slide space assume
mediates a wedge means 17 fixed to piston rod 13. The wedge surf-
aces of wedge means 17 support the wedge surfaces of an assess-
axed expander plate 19 in a manner that, when wedge means 17
slides forward (right in the fig. 2 case) in said slide space,
said expander plate lo works its way radially outwards from body
16 by the action of wedge surfaces as well as against the action
of springs 18. On the opposite side to said expander plate, the
periphery of said body is provided with a spacer plate 20 secured
to the body by means of fastening bolts 21. Springs 18 are also
secured to this spacer plate. This design is shown in more
detail in fig. 4 which also illustrates hydraulic circuit pass-
ages 1 and 2 in the side portion of body 16. The dimensions and
shape of spacer plate 20 are chosen according to the size of any
given hole that is surveyed.
The above-described clamping part 16 is fastened to a hammer part
body 27, this joint being sealed with seals 23. The joint is
further fitted with seal spacers 24 provided with apertures
aligned with the mouths of said pressure fluid supply passages
1, I To ensure the joint, said hammer part 27 is provided with
two mounting parts 25, 26 fixedly mounted on the body. Clamping
part 16 is fastened to the outer mounting part 25 by means of
screw threads. This mounting part 25 is sealed against hammer
part body 27 by means of seals 23 and 24. The other mounting
part 26 is fitted withes.
One end of mounting part 26 is fitted with the striking head 28
of hammer 29. Hammer 29 comprises a relatively large hammer
body, the end of which opposite to said striking head comprises
a narrower rod portion terminating in a hammer locking pin 32.
At the Homer neck portion there is a set of springs 31 whose
one end bears upon the hammer body and the other end bears upon
the front face of a locking bell 37, the latter forming one
termination of the hammer displacement space. Said locking bell
37 comprises an outer part 37 which is fixed relative -to body
27 and an inner part 38 which is movable thereon. The inner
locking bell part 38 comprises a cavity for receiving said
hammer locking pin 32. This cavity is provided with locking
.',
pi
balls 33 squeezing behind the ridges of hammer pin 32. Said
interlocking bell part 38 is further provided with a locking
bell pin 35 against which spring 39 is supported. The outer
locking bell part 37 in turn is provided with another locking
bell pin 36 against whiz}, the other end of spring I is support-
Ed
The termination area opposite to said locking balls 33 of inner
locking bell part 38 is provided with a stopper means 40 serving
to prevent the end portion of the hammer piston rod reciprocal-
in within said inner part 38 from coming out of said inner
part 38.
Piston rod 46 travels through a stopper part 41 which forms the
extension of locking bell 37. Stopper part 41 is secured to
body 27 with fastening bolts 43 and by means of seals 42 as well
as seal spacers 44 and their fastening bolts 45. Stopper 41
builds the other termination for the displacement area of piston
47 mounted on the free end of piston rod. In body 27, the press-
use fluid passages 1 and 2 are directed in a manner that passage
2 terminates in the cylinder space near said stopper part 41 and
passage 1 terminates near the opposite end of said cylinder
space.
The other end of said cylinder space consists of an end cap 50
mounted on said body 27. This end cap 50 is fitted with seals
48, which correspond to seals 10 of clamping part 16, as well
with a fastening bolt 49 for said seals, the latter bolt in turn
corresponding to bolt 11 of clamping part 16. This end cap 50 is
of the same shape as the clamping part end cap 8, so both of these
components can be suitably fitted with a cable connector 4.
However, in the case shown in fig. 7, said end cap 50 is fitted
with a blind cap 51, secured with a fastening bolt 52 to end cap
50. Said blind cap 51 is further provided with a through-hole
53 for electric connector 7 when said blind cap 51 is used as
a cable termination for connection to device.
Thus, as pointed out in the above description, the device of the
invention comprises two substantially cylindrical parts, i.e.
a hammer part body 27 as well as a clamping part body 16. The
free ends of both parts are similarly designed so that each end
of the device can be fitted with a cable connection piece 4 and
a blind cap 51. Such arrangement will be capable o-f producing
a pulse both Donnelly and uphold. Two hydraulic fluid passages
1 and 2 extends along the sides of both parts from part to part,
the sealing being ensured at joint sections by means of a sealing
system 10, 23l 48.
Cable 3 contains two hydraulic fluid supply lines as well as an
electric cable for detecting a pulse as well as possible other
connecting lines. The mechanical joint of hammer part 27 and
clamping part 16 is accomplished with rubber buffer means 30 in
a manner that during the impact the hammer part mass does not
affect the transmission of a pulse to the walls of a Barlow.
Operation of the device of the invention proceeds as follows:
As a pressure fluid is supplied into the passages, the pressure
fluid discharging from passage 1 causes the displacement of
piston 12 to its leftmost position (figs. 1 and 2). By the act-
ion of piston rod 13, this displacement also moves the wedge
part to its leftmost position while, at the same time, expander
plate 19 pulls itself by the action of springs 18 to its inner-
most position. At the same time, the pressure discharging from
passage 1 urges piston 47 to the left, whereby said locking bell
37 moves also to the left by the action of locking bell pin 36
compressing said spring 31 (fig. 10). This left ward displace-
mint of the locking bell proceeds thus compressing springs 31
until said hammer pin 32 meets said locking bell balls 33 in the
inner locking bell part 38. After this, said inner locking bell
part 38 does not continue the displacement but the outer part 37
moves to the left with respect thereto. Said spring 39 mounted
between locking bell pins 35 and 36 tightens and, as the disk
placement continues, locking bell balls 33 meet recesses 34 made
in said outer part 37 and squeeze themselves into these recesses.
Thus, said hammer pin 32 is capable of passing looking bell balls
33 towards inner locking bell pin 35. After said hammer pin 32
has passed them, said locking boll balls drop again out of their
recesses behind pin 32 it -the same lye quisling inner part 38
moves to some extent along wealth outer part 37. At the same time,
the end of pin 32 hits stopper row 35 and the displacement stops.
As this situation is reached, pressure in the device will rise
giving notice to the operator on the ground that -the device is
loaded. Hence, the flow in fluid passages is reversed in a man-
nor that the fluid on the opposite side of pistons 12 and 47 will
return to a pressure tank on the ground. This is followed by
the pressurization of passage 2 causing pistons 12 and 47 to move
simultaneously to the right. Due to this action, wedge part 17
moves retreads in contact with expander plate , the wedging
action causing said expander plate to extend radially from body
16 into engagement with the wall of a Barlow. The spacer plate
20 on the opposite side of said expander plate urges against the
opposite wall of said Barlow. As pointed out above, the thick-
news and shape of spacer plate 20 are chosen according to the
diameter of a surveyed Barlow. Thus, the device can be readily
employed in Berlioz of various sizes.
Now, piston 47 will also move retreads anon reaching a stopper
40 mounted on inner locking bell part 38, it will pull along the
entire locking bell assembly 37, 38, hammer 29 as well as the
compressed springs 31.
At the same time, pressure keeps increasing on the left side of
piston 12 making said expander plate 19 urge still more firmly
against the wow of a Barlow.
As piston 47 and its rod 48 move retreads (figs. 12, 13), the
locking bell assembly meets stopper part I Thus, the movement
of outer part 37 stops but piston 47 proceeds and so does said
inner part 38 connected to the locking bell piston rod 46, said
inner part pulling along hammer 29 by means of locking bell
balls 33. As the displacement continues, said locking bell balls
33 meet recesses 34 and fall therein releasing their grip from
g
hammer 29 with the result that the force of springs 31 will hurl
said hammer 29 towards anvil or striking head 28 for the general-
ion of a desired pulse.
To encourage its impact, said Henry 29 is provided with length-
wise slots 54 facilitating air passage along these slots (fig. 6).
The inertial mass of wedge part 17 provides a highly firm contact
between expander plate 19 as well as spacer plate 20 and the
walls of a Barlow.
it the moment of impact, a built in shock micro switch 9 breaks
the electric contact and so triggers a measuring or recording
unit an the ground.
With piston 47 in its rightmost position, the movement stops and
pressure increases. This indicates to the operator that the
shock has taken place and pressure can be resupplied to passage
1 and the operating cycle can be restarted from the start posit-
ion.
The above description deals with one embodiment of the invention
to which the invention is by no means limited. For example, it
has been said above that the operator on the ground can conclude
from the increase of pressure that the device is loaded and thus
pressurize the owner hydraulic circuit etc. In this respect,
however, it must be appreciated that the operation may be fully
automatic.
