Note: Descriptions are shown in the official language in which they were submitted.
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~ I~RODUCTI~J
: T~IS I~YEhTIOl~ relates to an automatic
swimming pool cleaning device of the kind wherein ::
means are provided for interrupting flow of water
sucked through the device to thereby cause the
device to move across a submerged surface to be
cleaned.
BAC~GROU~D TO T~E I~V~I~J
The above type of device is well known and
is described 1n various patent speci~ications such :
as South African Patent ~o 71/1024 (Raubenheimer),
United States Patent ~o 4023227 (Chauvier), and
United States~Patent ~o 4133068 (Hoffmann). ~ :
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It is an object of this invention to
provide a swimming pool cleaning device which
operates efficiently and is less susceptible to
operational malfunction caused by foreign matter
becoming lodged within the device compared with
many prior art devices.
SU~MA~Y OF T~E I~VENTIO~
According to the invention there is
provided a swimming pool cleaning device comprising
a head having an inlet opening adapted to be
1~ located adjacent a submerged surface to be cleaned,
an outlet from the head connected to the inlet
through a flow channel, a valve associated with the
: flow channel and biased to an open position, the
valve being arranged to mov~ to a closed position
to at least substantially close the flow channel
intermittently when water flows through the channel
in use, and a variable volume chamber communicating
- with the flow channel downstream of the valve and
bi~qed to a di~tended c~ndition for enhanc~ng
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operation of the valve in use, the head and flow
channel being operative to cause movement thereof
across a submerged surface in consequence of the
intermittent closure of the valve, in use.
Further features of the invention provide
for the valve to be either a spring loaded plunger
valve or a pivotable flap valve arranged to
co-operate with a valve seat formed in the flow
channel; for the variable volume chamber to be
located either in a branch off the flow channel or
to form an enlarged ~one of the channel in its
length; and for the variable volume chamber to
comprise a cup shaped diaphragm. As an alternative
the variable volume chamber may comprise a spring
~ 15 loaded piston acting in a cylinder.
- The invention also provides for the spring
loading of the plunger or flap valve to be
adjustable, and, for adjustible means to be
associated with the variable volume chamber for
urging it to a distended condition.
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Preferably the head is of the type in
which the inlet is located within a oot of the
head, the foot being surrounded by a flexible disc
and wherein the channel extends at an incline to
the disc and thus at an incline to the submerged
surface being cleaned.
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These and further features of the
invention will become more apparent from the
following description of various embodiments
thereof given below by way of examples with
reference being made to the accompanying drawings:
BRIEF DESC~IPTI~ OF THE DR~UI~GS
~ In the drawings:-
-~ Figure 1 is a cross-sectional side elevation of one
form of swimming pool clean-ing device
~cco-ding to the invention,
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Figure 2 is a similar view through a second
embodiment of the invention; and,
Figure 3 is a similar view through an alternative
variable volume chamber for the embodiment
of Yigure 2.
DETAILED DESCRIPTI~ 0~ T~E DRA~GS
Referring initially to Figure l, a
swimming pool cleaner is shown whereof a head l,
has an inlet opening 2, an outlet opening 3 and a
flow channel 4 connecting the inlet with the
outlet. A plunger type of valve, having a plunger
5 carrying a closure 6 and being slidable in a
cylinder 7 therefor is arranged such that the
closure can engage a valve seat 8 encircliny the
flow channel near the inlet end to close the flow
channel through the head l intermittently as will
be described below.
A tension spring 9 biases the plunger 5
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away from the valve seat 8. One end of the
tension spring is mounted inside the plunger, which
is hollow, and the other end lO is mounted to a
screw threaded plug Ll which screws into the back
of the cylinder 7. By screwing the plug into the
cylinder to a greater or lesser extent the tension
on the spring 9 can be adjusted.
The closure 6 is of a shape and
configuration which will ensure that when, in use,
water is drawn through the flow channel from the
inlet to the outlet the plunger will be drawn
, towards the valve seat 8 against the action of the
- tension spring in order to substantially close the
valve intermittently.
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- 15 Such intermittent closure of the valve is
enhanced, as provided~by the invention, by the
:: presence of a variable volume chamber 12, which, in
this embodiment:of the invention, assumes the form
of a cup shaped elastomeric diaphragm 13 having its
periphery attached to a ri~la pLate 14 ~arried ~n a
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connecting tube 15 communicatiny between the inside
of the variable volume chamber and the channel 4.
The diaphragm, being elastomeric, is automatically
biased to a aistended condition but the bias is
- 5 enhanced by the presence of a compression spring
- 16.
A foot 17 is formed around the inlet 2,
the foot 17 having a suction port 18 formed therein
for allowing by-pass water to enter into the inlet
2. A flexible disc 19 is fitted around the foot
17 and, in use, the dise 19 and foot 17 will be
located against a surface 20 to be cleaned.
- The foot and disc are arranged such that,
when they are in firm contact with the submerged
surface, the axis of the flow channel i5 inclined
to such surface at about 45 for reasons tbat will
be quite apparent to those skilled in the art.
- The outlet 3 is, for use, connected
through a swivel coupling 21 to a flexible hose
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(not shown), the hose being connected to the
suction side of a pump which will, in use, draw
water through the head and the hose to a swimming
pool filter.
In use, as water is drawn through the head
: 1 the plunger 5 will be urged to move against the
action of the tension spring so as to move the
closure towards, and generally fully onto, the
` valve seat 7. As the closure 6 strikes the valve
seat 8 the flow in the flow channel 4 is
interrupted and pressure in the flow channel 4 is
suddenly decreased. This decrease in pressure in
the flow channel is conveyed through the connecting
: tube 15 to the interior of the variable volume
chamber. This causes the diaphragm 13 to collapse
.: against the action of the compression spring 16,
thereby, at least to some extent, xelieving the
suction orce inside the flow channel 4 and
allowing the closure 6 and plunyer 5 to moYe away
from the valve seat 8 under the action of the
tenslon syring 9
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- The ~low will thereafter recommence
through the flow channel and the closure will once
again be drawn against the valve seat 8 to thereby
repeat the cycle. This cyclical opening and
closing of the flow channel will cause the pool
cleaning device to move across the surface 20 to be
-: cleaned by the virtue of the inclined, and thus
non-symmetrical axial direction in which the flow
channel extends.
10 It will be appreciated that in order for
the device to operate properly, and over a wide
range of suction pressures, it is important that
the arrangement of the various components be
optimally selected. Thus, the dimension indicated
in Figure l by the letter "x", which is the
distance between the valve seat 8 and the inlet to
the connecting tube 15 as well as the dimension
indicated in Figure l by the letter "y", which is
the length of the connecting tube 15, should be
- 20 selected with a consideration of the flow and
hydrostatic forces which arise in a device of this
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nature operating in these conditions. ~Jhere the
length of the connecting tube is appreciable it
may, of course, be coiled for convenience. The
diameter of the flow channel 4 and that of the
connecting tube 15 are also important elements to
be taken into consideration. The final
configuration will of course depend on the range of
suc.ion pressures with which the device is to
operate and the desired flow rate through the
device. For specific applications the force on
the tension spring 9 and the compression spring 16
may be adjusted or the springs may be replaceable
r by more appropriat ones.
~ere required a flow control valve may be
fitted in the suction hose or flow channel to
provide optimal flow rates for any specific
cleaning device or setting thereof.
It will be appreciated that the variable
volume chamber 12 may take a different form from
-; 20 that described above Specifically, as shown in
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Figure ~, there is envisaged a piston 22 movable in
a co-operant cylinder 23 carried by a connecting
tube 24 whereby the interior 25 of the piston and
cylinder assembly communicates with the flow
channel. The piston is biased by a compression
spring 26 towards a position in which the interior
is distended as required by the invention. The
interior can therefore change in volume very much
along the lines of the diaphragm arrangement
described above.
A further alternative is illustrated in
Figure 3 in which the variable volume chamber 7,
assumes the form of an enlarged zone of the flow
channel, the chamber being defined by an
elastomeric wall 28 which is sufficiently rigid so
as not to re~uire a spring to urge it towards the
distended condition.
Figure 2 also illustrates an alternative
form of valve. In this case the valve closure 29
assumes the form of a flap pivotally mounted at a
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position laterally off-set above the valve seat 30
which is simila~ly located to that illustrated in
Figure 1. A compression spring 31 serves to bias
the valve to the open position such spring being
located between the periphery of the valve seat and
the pivot 32 carrying the flap valve closure. In
this case a adjustable stop 33 may be provided to
limit the movement of the flap valve in the
direction of opening thereof.
l~umerous other variations can be made to
the embodiment of the invention described above
without departing from the scope of the invention
which is limited only to the presence of a variable
volume chamber communicating with the flow channel
through the device which has a valve biased to the
open position in its flow channel.
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