Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
FIELD OF THE INVENTION
. The invention ~elates to a method and apparatus for
producing a sprinkle~ hose which incl~des a first hose region
for the supply of water and a second substantially parallel
hose region integral with the first region and including a drip
region that communicates with the water supply region through
throttled inlet openings which may be disposed singly or in
~roups at some distance from one another. Furthermore, the in-
: terior of the hose has thro~tled passages leading to trickle
openings through whïch water finally emerges from the hose indroplets.
BACI~GROUND OF THE:INVENTION
AND PRIOR ART
A sprinkler hose of the general type described above
which is formed in one instance from a two-layer folded~plastic
sheet and in another instance from a continuous tube is known.
The hose is then provide~ with a longitudinal seal which de-
fines transverse openings. A portion of the hose which consti-
tutes a drip section i9 provided with trickle openings,through
which the water emerges in droplets. Furthermore, associated
with each
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connecting opening and each trickle opening are short welded
seals or spot welds which throttle'the flow of water so that
the volume of water ~lowing through the'trickle openings is rela-
tively small. The sprinkler hose described in the aforementioned
publication is intended for the purpose of so~called trickel
sprinkling and is relatively simple to manufacture. However,
it is practically impossible to produce a hose in which the pres-
sure drop along the path from the one or more connecting openings
up to the trickle openings remains well-defined. Accordingly,
the required throttling can be obtained only by making the trickle
openings very small, i.e., with very minute cross sections. How-
ever, in operation these openings tend to become enlarged so that
the rate o'f water release per unit length of hose becomes very
non-uniform over the length of a given sprinkler hose.
Another type of sprinkler hose is known in which the
entire lenth of the hose serves to supply water in and in which
a fold of the hose wall is separatedl from the remainder of the
hose by welded seams and contains capillary water lines. As
before, the problem of maintaining a precisely defined pressure
drop in the capillary lines up to the water outlet exists in this
example.
Still another hose for trickle sprinkling consists of a
first tube made from a sheet and a second tube which contains me-
andering channels and is welded to-the first tube. The meandering
channels communicate at one end with the'interior tubing and have
a
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.~
trickle opening at the other end. The hose described in this
publication is produced by guiding a sheet of material over a
vacuum deep-drawing roller which has a ~acuum zone in a portion
of its circumference. The sheet material is pulled into given
depressions of the roller when passing through the ~acuum zone.
Subsequently, the formed sheet is welded to a second sheet.
This method of production is not economical for large-scale manu-
facture because the roller must not only deform and weld the ma-
s terial but must also cool it off. Such a roller would have to
be of extraordinarily large dimensions to serve for a sufficient
rate of mass production.
Still another sprinkler hose consists of an inner
smoothtube surrounded by an outer tube containing helical chan-
nels. The inner tube has connecting openings and the outer
tube has trickle openings. In principle, the spiral channels
serving to decrease the pressure as between the connecting openings
and the trickle openings are very suitable but they are very dif-
ficult to produce in the required small tube diameters.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of the invention to provide a method
and an apparatus for producing a sprinkling hose especially for
trickle discharge which~has a water supply region and a trickle
discharge section and wherein the pressure drop in the trickle
discharge section is well-defined and remains stable in operation
in a continuous working process.
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~6~
According to the present invention there is provided a
method for the continuous manufacture of a flat-shaped hollow
body, equipped ~ith fluid transport ducts, which have fluid en-
try ports and fluid exit ports, using a forming die consisting
of continuously-mo~ing mold segment halves, moving along a form-
ing line which, upon entering the forming line, are moved through
the forming line in close contact with each other in the operat-
ing direction and with the forming die closed on pairs of mold
segment halves, wherein a warm thermoplastic hose stock is intro-
duced into the forming die and formed there under vacuum, whereinsaid hose stock has a relatively large wall thickness, and wherein
the hose stock, in at least a portion of its cross section, is
subjected to vacuum action before the pairs of mold segment hal-
ves are brought together and then pressed together thereby form-
ing voids and welds over at least a portion of its cross section.
The sprinkler hose normally has a water supply section
or tube which is parallel to a trickle discharge section in which
there is a plurality of closed chambers at least one of which
communicates with the water supply section through throttle inlet
openings. Furthermore the chambers communicate with one another
through secondary throttle channels and the last chamber in the
trickle region has at least one trickle outlet for permitting
the exit of droplets of water. The aforementioned characteristics
insure that the throttling conditions are pre-
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cisely defined, i.e., that the pressure drop between the throt-
tle inlet openings and the trickle outlet is defined exactly.
By arranging the chambers in at least two parallel rows and by
offsetting chambers in different rows from one another, a large
number of connecting throttle openings may be disposed in a
given length of sprinkling hose. By making the cross section of
the chambers large with respect to the connecting throttle pas-
sages, the throttling or pressure
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i~.~P,6
occurs almost exclusiYely across the connecting throttle open- -
ings and not in the chambers themselves. The connecting throt-
tle openings between the chambers are slit-shaped which makes it
possible to define a precise amount of throttling for each con-
nection. In a particularly favourable embodiment of the inven-
tion, the sprinkler hose is doubled up so that it constitutes a
mirror-symmetrical object with two adjacent trickle regions and
two external water supply regions. The advantage of this con-
struction is that the pressure drop occurs from the point of
water supply to the end of the hose and back again. The sum of
the pressures in each of the hose sections of a given transverse
plane is approximately constant so that two adjacent trickle open-
ings would release together a sum of water which remains constant
over the entire length of the hose.
A favourable feature provides that chambers in adjacent
rows of chambers communicate with one another through connecting
throttle openings so that the flow of water through the trickle
region of the hose is constantly bent by approximately 90. Ano-
ther favourable feature is the provision of a dead-space chamber
communicating with the first of the trickle chambers of the hose.
Accordingly, any contamination or dirt in the stream of water
which has entered the first trickle chamher in a row of chambers
may be deposited in the dead space chamber and thus would not be
detrimental to the operation of the hose. The entry of contamina-
tion or dirt into the trickle region is generally impeded by a
favourable feature of the invention which provides that the throt-
tle inlet
-- 5 --
~ ~6~
openings from the supply region to the trickle region are
inclined in a direction which is opposed to the direction of
water flow through the water supply region. Furthermore, any
dirt which actually enters the trickle region of the hose can
easily be dislodged, for example by tapping on the hose with
a light hammer, because the hose itself is made from a very
soft plastic material, for example high pressure polyethylene
or soft PVC and the wall-thickness of the hose is low, for -
example from 0.3 - 0.5 mm.
An object attained by the method of manufacture of the
sprinkling hose is the production of the hose in a single and
continuous working process without requlring the manufacture
of an intermediate product. This object is attained by
providing that a still warm and plastic hose is compressed
and joined by welding on portions of its cross section while
other portions are left free to form the chambers, connecting
throttle openings and throttling inlets. The method of manu-
facture includes the provision of an endless train of mold
halves, pairs of which are moved towara one another and
enc]ose the still warm and plastic hose, thereby shaping and
forming the hose while portions of the hose are shaped by
means of applying a vacuum to selected portions thereof.
In particular, portions of the hose are subjected to vacuum
prior to the conjunction of two mold halves. In this manner,
the still warm and plastic hose is preformed by the application
of vacuum prior to the complete closure of the mold. This
step of the method is of great importance because the hose
according to the invention has a large number of welded joints
~L~L68 LJ~2
;. .
e
especially in the vicinity of the trickle region. If the
hose were not subjected to prior vacuum suction, this welding
would cause the walls of the hose to adhere to each other over
the full length and width of the trickle region. The prior
application of vacuum prevents such overall adhesion zn~ permits
adhesion only where subsequent welding is actually intended.
In particular, the cross-sectional region o~ the trickle
section is subjected to a prior application of vacuum. In
order to prevent that that part of the still warm and plastic
10 hose which is to form the water supply region ~rom being squeezed
in between the closing mold halves, this part of the hose is
subjected to vacuum only after the mold halves are already
closed. However, the prior application of vacuum takes place
only a very short time before mold closure. In particular,
15 the vacuum application ma~ begin approximately 0.03 - 0.10
seconds prior to the closure of the mold. In order to enhance
the preforming of the still warm and plastic hose a small
amount of pressure is maintained in the interior of the hose.
In particular, the pressure may lie between 0.01 and 0.05 bar.
In order to insure that the still warm and plastic hose
enters the mold correctly, the method of manufacture according
to the invention provides that the still warm and plastic hose
is pressed together and flatened prior to the application of
vacuum.
The invention also includes an apparatus for producing
and manufacturing the sprinkling hose according to the invention.
It is a particularly favorable feature of the apparatus of the
inve~tion that it provides two endless mold trains each of which
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carries mold halves which are conjoined at the inlet of the
crest to form pairs of molds which follow one another at
very~close distances. Pairs of molds have appropriate an~
cooperating recesses and also include internal vacuum channels
which are brought into communication with vacuum channels
contained in the table on which the mold halves move so that
a vacuum may be applied from the machine table to the mold
halves prior to the closure of the mold. By suitable con-
struction and positioning of the cooperating vacuum channels,
only a particular region, i.e., the region in which the
trickle section is formed in the still warm plastic hose,
will be subjected to vacuum for the purpose of preforming~
In order to provide for subsequent application of
vacuum to other parts of the mold, the apparatus contains
secondary independent vacuum bores which cooperate with
different parts of the mold and which are subjected to
vacuum at a time later than the first set of vacuum channels.
In particular,the first vacuum channels in the mold are
closer to each other than the secondary channels and the
vacuum supply channel in the mold table undergoes a widening
in the direction of the travel of the mold halves so that
the secondary vacuum channels are subjected to vacuum at
- - a time later than the first set of vacuum channels~
~ The apparatus of the invention provides for production
speeds of up to 30 meters of finished sprinkler hose per minute.
It has been found to be particularly favorable for the purposes
of the invention if the wall thickness of the sp~inkler hose
... ~ . -. i.... .
is between 0.3 and 0.5 millimeters. This low thickness also
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1~68~
substantially reduces the material expenditure for a yiven
length of sprinkler hose.
Other advantages and characteristics of the invention
will emerge from the description of preferred exemplary
embodiments which relate to the drawing.
THE DRAWI~G
Fig. 1 is a planar section through the sprinkler hose
according to the invention along the lines I-I in Figs 2 or
4;
Fig. 2 is a section through the trickle region of the
hose along the line II-II of Fig. l;
Fig. 3 is a section through another row of chambers
ln the trickle region of the hose along the line III-III
in Fig. l;
Fig. 4 is a cross section of the hose along the line
IV~IV in Fig. l;
Fig. 5 is a cross section through a chamber of the
hose having a bulge for defining a trickle opening and is
made by a section along the line V-V of Fig. 1;
Fig. 6 is an illustration of a roll of sprinkler hose
according to the invention in a side view;
Fig. 7 is an enlarged partial section of the roll o~
hose of Fig. 8 along the sectional line VII-VII;
Fig. 8 is a side view of the roll of hose of Fig. 6;
Fig. 9 is a cross section through the profile of a
second embodiment of a sprinkler hose of the invention having
_g_
three adjacent rows of trickle chambers and in which the
main water supply region has a teardrop-shaped cross section;
Fig. 10 is an illustration of a top view of the hose
of Fig. 9 with portions shown in section;
Fig. 11 is a cross-sectional view of the embodiment
of Fig. 10 along the line XI-XI;
Fig. 12 is an illustratlon of a combination o two
adjacent sprinkler hoses with adjacent trickle regions;
` Fig. 13 is a top view of the arrangement of Fig. 12;
Fig. 14 is a cross section through the illustration
of Fig. 13 along the line XIV-XIV;
Fig. 15 is a partial top view of a molding machine
~or producing the sprinkler hose according to the invention
along the line XV-XV in Fig. 17;
Fig. 16 is a vertical section through the apparatus
of Fig. 15 along the line XVI-XVI;
Fig. 17 is a vertical section through the apparatus
of Fig. 15 along the line XVII-XVII;
Fig. 18 is a vertical section through the apparatus
of Fig. 15 along the line XVIII-XVIII; ana
Fig. 19 is a vertical section through the apparatus
of Fig. 15 along the line XIX-XIX.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
The first embodiment of the sprinkler hose 1 according
to the invention is shown in Fig. 1 to exhibit an uninterrupted
main water supply region 2 and adjacent and parallel thereto
a trickle reyion 3 which serves to distribute the water
received from the supply region 2. As will be seen from
the various illustrations 1-7, the hose region 2 may be
relatively flat with approximately plane parallel side walls
4, 5 and approximately semicylindrical transition regions 6,
7 joining the side walls 4, 5.
The trickle region 3 adjacent to the water supply reyion
2 includes and deines a plurality of rows o~ mutually dis-
placed suhstantially cylindrical trickle chambers 8, 9. In
the exemplary embodimenk according to Figs. 1-8, the hose has
two rows of chambers 8, 9. Adjacent ends of the cylindrical
chambers 8 of one row and those of the chambers q o~ the
other row are placed-in communication by means of slit-shaped
connecting throttle openings 10. The irst chamber 8 of e~ch
assembly of chambers 8, 9 communicates with the main water-
carrying tube region 2 through slit-shaped inlet throttle.`
openings 11. The slits defining the openings 11 are very
.narrow as it is illustrated in particular in Fig 3~ Further-
- more,they are inclined in a direction opposite to the direction
of flow 12 of the water within the hose region 2~as best seen
in Fig. 1, so that any dirt particles carried by the water
would tend to continue to flow in the direction of flow 12
within the region 2 rather than be carried into the cascading
or meandering rows of cylindrical chambers 8, 9 along the dash-
-11
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~ 68~)~Z
dotted line of flow 13. The first of the cylindrical chambers
8 in each of the assemblies of chambers 8, 9, i.e., the chamber
which co~nunicates with the hose region 2 through the
inlet openings 11, is joined to a dead-space chamber 14 across
a throttling channel 10. l~he dead-space chamber 14 serves to
hold any dirt particles which may have entered the cascade o
trickle chambers 8, 9. The dead-space chamber 14 is located
in the row of ch~nbers 9.
The last of the chambers 8 of a given cascading assembly
of chambers 8, 9, all of which communicate w~th one another
through connecting throttle openings 10, is provided with
a trickle opening 15 which is defined in a bulge 16 of a
wall 17 o the chamber 8. The trickle opening 15 is a slit
within the bulge 16,as best seen in Fig. 5, so that the opening
de~ined thereby does not throttle the water flow but substan-
tially closes in the absence of any water pressure so that it
prevents dirt and contamination from entering the cascade of
trickle chambers 8, 9 through the trickle op~ning 15~ As
will be seen especially from Figs. 2, 3, 4, the wall 17 is
a continuation of the side wall 4 while the wall 18 lying
opposite the wall 17 is a continuation of the side wall 5
of the hose region 2~ These two walls 17, 18 are joined
together by welding everywhere except at the location of the
cyllndrical chambers 8, 9, the dead-space chamber 1~, the
connecting throttle openings 10 and the inlet throt~le openings
11. The joined and welded paxts of the trickle region 3 are
shown in Fig. 1 by means of cross-hatching. It should be
especially noted that no co~nunication whatever exists
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1~ ~8~
between the last cylindrical chamher 8 containing a trickle
opening 15 of a particular set or cascade of chambers an~
the next following set or cascade of chambers, the first
chamber 8 of which will have an inlet throttle opening ll
and possibly a dead-space chamber 14. The two sets or
cascades of trickle chambers 3 are separated from each other
- by a complete welded joint 20 which prevents any communi-
cation thexebetween, as is especially evident from Figs. 1-3.
Due to its shape and high flexibility, the sprinkler
hose l according to the invention as described above is
capable of space-saving storage by means of spooling on a
roll. This is shown especially in Figs 6-8 in which the
spool diameter 21 can be relatively small (Fig. 6).
Furthermore, substantial space may be saved during roll-up
by displacing adjacent layers of the hose 1 by the width
of a chamber 8 or 9 as ~est seen in Fig, 7. The siae walls
4, 5 undergo elastic~deformation during such storage. When
the sprinkler hose l is removed from the rolL 22, the cross
section of the hose reassumes the shape illustrated in Figs. l
and 4. The roll 22 may be held in place by simple means, for
example ties 23.
In a second émbodiment of the invention illustrated in
Figs. 9-11, the spxinkler hose 1' has a water supply region 2'
whose cross section is drop-shaped. Furthermore, the hose
is provided with an additional row of cylindrical chambers
Z4 disposed between the cylindrical chambers 8' and 9' whose
function is similar to that of the chambers 8 and 9 o~ the
first embodiment. Each of the chambers 24 is approximately
-13- ~
~61~Z
half as long as the chamber 8', 9'. As before, the chambers
8' and 9' overlap one another substantially and a communication
is established through a connecting throttle opening 10'
between one end of a chamber 8' and the adjacent end of a
chamber 24 as well as between the opposite ena of the same
chamber 24 and the adjacent end of a chamber 9'. In this
emhodiment, the first cylindrical chamber 8' of a given
cascade of chambers communicates with the water supplying
hose region 2' through four inlet throttles 11'. A aead-
chamber 14' is disposed at the start and finish of each
cascade and lies,respectively,in the rows containing the
chambers 24 and 9'; these dead-space chambers 14' communi-
cate with the hose region 2 directly through channels 25.
.....
The disposition of three rows of chambers in the embodi-
ment provides for a substantially larger number of connecting
throttle openings 10' per unit length of sprinkler hose 1'
resulting in an increased flow path and thus an increased
amount of throttling and pressure drop for the trickle dis-
charge.
A sprinkler hose according to the first emboaiment -
illustrated in Figs. 1-5 or the second embodimen~ illustrated
in Fig. 9 is made operational, i.e., is prepared for actual
- use, by taking a given length of hose 1 and applying ~o an
upstream end thereof a hose connection 26,for example, by
means of a common hose clamp 27. The downstream end of this
single sprinkler hose 1, 1' is closed by means of a plug 28
which also may be held in place by a hose clamp 27. During
the installation of the hose clamp, the adjacent trickle region
-14-
:,'
. 3 or 3' is wrapped around the hose region 2, 2' and i5
: clamped shut by hose clamp 27 so that water can emerge
from the hose only through the trickle opening 15 lying
downstream in the sense of the direction of flow 12. In
. 5 order to facilitate the clamping and closure of the end
of the hose, the welded joints 20, 20' may be severed up
to the hose region 2, 2'.
The water which flows in the hose region 2, 2' in the
direction 12 enters the inlet throttle open.ings 11, 11' along
the flow lines 13, 13' and passes into the numerous cylindrical
chambers 8, 9 or 8', 2~, 9' and is subjected to a pressure
drop during the passage through each of the connecting throttle
openings L0, 10'. When the water reaches the trickle opening
15 at the termination of a cascade of chambers, the water
pressure is so low that it exits from the openings 15 in the
form of individual drops 29, as illustrated schematically in
Fig. 11. Inasmuch as the trickle openings 15 are advantageously
located in a chamber 8, 8' which is immediately adjacent to the
water-carrying hose region 2, 2' the opening 15 never actually
makes contact with the ground 30 due to the substantially
larger diameter of the region 2 and is thus protected against
contamination.
The distance in the direction of flow 12 between the
consecutive trickle openings 15 substantially corresponds to
the length of a cascade of chambers 8, 9 or 8', 24, 9'. This
separation or distance may be defined as a division t of the
overall sprinkler hose 1~ 1'. If the size of the cylindrical
chambers 8, 9 or 8' 24, 9' remains the same and if the cross-
. .
: -15-
~ti8~
section and shape of the connecting throttle openings 10, 10'
and the lnlet openings 11, 11' also remain the same, then
the pressure loss in a cascade of chambers will be increased
by an increasing value for the variable t. The greater the
pressure loss, the smaller is the number of drops 29 which
emerge from a trickle opening 15 per unit of time if the inlet
water pressure in the hose region 2, 2' remains the same.
The sprinkler hose according to the invention may be used
in a double configuratian illustrated in ~igs. 12-14. In
practice,a double sprinkler hose 1" may be manufactured and
for such use as where only a single hose 1 or 1' is required,
the double hose 1" is split through the central symmetry plane
31. In a double sprinkler hose 1", the hose region 2" is also
of teardrop-shaped cross section as was the case in the embodi-
ment of Figs. 9-11. The trickle region 3" associated with each
hose region 2" is the same as the trickle region 3 of the
embodiment of Figs. 1-5 and the remarks made with respect
thereto also apply here. In the embodiment as a double
sprinkler hose 1", one end of the hose receives a hose con-
nector 26 which is fastened in place by a hose clamp 27. The
adjacent other end of the hose 2" is closed by a plug 28 held
in place by a similar hose clamp 27. The opposite ends of the
two regions 2" are connected by means of a bent pipe 32 also
held in place by hose clamps 27. In order to permit the
entry of the adjacent parts of the txickle regions 3" into
the clamps 27 which hold the bent tube 32, it is necessary
to make a cut 33 in both trickle regions 3" so that these parts
of the regions 3" may be wrapped around the regions 2". When
so clamped, the passage of water out o~ a cylindrical chamber
-]6-
is positively prevented so that water can exit onl~ through the
trickle openings 15. As was the case in the other embodiments~
the trickle openings 15 do not make contact with the ground 30
due to the substantially larger diameter of the regions 2" (see
Fig. 14).
An apparatus for manufacturing the sprinkler hose 1,1'
or 1" according to the invention is illustrated in part in Figs.
15-19~ This apparatus includes a plurality of mold halves 34,
35 which are guided on a pair of endless tracks and in which pairs
of mold halves 34,35 ap~roach one another and finally join to-
gether to define a hollow mold section within which a length of
sprinkler hose is formed. The overall cross section of the mold
halves 34,35 is-rectangular and the mold halves are guided over
the surface of a flat machine table 37. The opposing faces 38,
39 of the mold halves 34,35 are appropriately configured to define
one-half of the external profile of the sprinkler hose to be form-
ed therein. At the start of the molding line 36, the pairs of
mold halves 34,35 pivot toward one another. Also located in this
area of the mold line is the extrusion nozzle 40 of a plastic
extruding machine, not shown in further detail and assumed to be
of known construction~ from which emerges a warm substantially
cylindrical plastic hose or tube. Pivotably disposed on or near
the extrusion nozzle are two pivotal arms 42,42' which rotate
around vertical bolts 41 and which are adjustable. The free ends
of the arms 42, 42' carry rollers 43 which can turn
3Q
"\
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around vertical axes 44. The rollers 43 serve to impart
some fla~ning to the previously circular hose 45 emerging
from the extrusion nozzle 40. The rollers 43 are also used
to adjust the wall thickness of the hose 45 being extruded
by appropriate adjustment o~ the direction of flow. At the
outset, the pivotal a~ms 42, 42' carrying the roller 43 are
placed in the retracted position shown in dash-dotted lines
in Fig. 15. Only after the hose being extruded with sub-
stantially circular cross section has been grasped by the
mold halves 34, 35 and has been guided into the mold line
are the pivotal arms 42, 42' moved inwardly,thereby causing
a deformation and adjustment of the hose 45. Thereafter, the
bolt 41 is fixed and the pivotal arms 42, 42' are fixed in
their operative position. The width of -the fla~ened hose 45'
is smaller than the width of the finished sprinkler hose 1,
1' or 1". An air channel 47 within the extrusion core 47 of
the extrusion nozzle 40 carries air at a very low pressure o~
approximately, fo~ example, 0.01 - 0.05 bar which serves to
maintain and correct the profile of the fla~ned hose 45'.
The mold halves 34, 35 are so displaced as to assume an
intially parallel relative position subsequent to entry into
the mold line 36. In that position the now parallel mold
halves 34, 35' are at a distance from one another such that
the faces 38, 39' are farther apart than the width of the
fla~ened hose 45'. In this position, the corresponding mold
halves 34, 35 are engaged by respective parallel rails 49
which guide the mold halves into closer and closer juxta-
position. As will be seen from Fig. 15, the end faces 50, 51
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of the various pairs of mold sections 34, 35 are in immediate
and planar contact with one another in the mold line. The
molds composed of mold haves 34, 35' are advanced along the
guide rails 4g until the faces 38, 39 are in direct contact.
Subsequently,they are guided in straight lines by guide rails
52 that are extensions of the guide rails 49.
As best seen in Fig. 17, each of the mold halves 34,
35 is provided with a vacuum bore 53 which extends down to
the bottom face 55 adjacent to the top of the machine table
37. The bores 53 closest to the adjacent faces 38, 39 communi-
cate through openings 56 in the shape of elongated slots with
the central region o~ the mold recess 57 in which the trickle
regions 3 and the adjacent transition regions 7 are formed.
The top of the machine table 37 contains open vacuum
channels 58 which are overlapped ~y the aforementione~ vacuum
bores 53 when the mold halves 34, 35 are pushed together by
the parallel guide rails 49 into a position in which ~hey are
still separated. At that time,the vacuum bores 53 and thus
the openings 56 are subjected to a vacuum with the consequence
that the central region of the hose 45 is urged against the
sides 38 and 39 of the mold halves 34, 35, respectively, in
the area of the mold recess 57. This process causes a pre-
forming of the hose in the central region. The entire top
of the vacuum channels 58 is covered by the mold halves 34, 35
when vacuum is applied so that no external air enters these
channels. The vacuum may be produced by known and customary
means. The mold halves also contain exterior vacuum bores
54,as best seen in Figs. 18 and l9,which communicate wi-th
--19-- ~
;;
transverse bores 60 closed externally by plugs 59 which
in turn communicate with elongated slots 61 that enter the
; uppër and lower regions of the mold recess 57 in which ~he
hose regions 2 are formed. The associated vacuum channels
54 are subjected to vacuum at the time when the two mold
halves 34, 35 are in direct and immediate contact, i.e.,
when the faces 38, 39 touch, as shown in Fig. 18. The
application of vacuum takes- place by the movement of the
mold halves over a part of the machine table in which the
vacuum channels 58 are widened to define vacuum channels
62. This application o vacuum causes the final shaping
and molding of the hose regions 2 from the position shown
` in E'ig. 18 into the position shown in Fig. 19~ although the
degree of final deformation is substantially less in the
vertical direction than would appear to be the case from
Fig. 18 which is exaggerated for illustration. The actual
deformation in the vertical directions is no greater than
approximately 1 - 2 millimeters. In the position of the
mold halves illustrated in Fig. 18, i.e., when they are
in direct contact, the walls 17, 18 are welded together in
the area of the trickle regions 3 at weld locations 19 and 20.
In order to prevent the side walls 4, 5 rom adhering
to the walls of the recess 57 of the mold and thereby causing
an undesirable reduction of the wall thickness of the transi-
tion region 6, it is suitable according to the invention to
shape the hose in the manner illustrated in Figs. 9-12 with
a teardrop-shaped cross section 2' and 2'lo This shape is-
therefore advantageous from a manufacturing point of view.
-20-
Furthermore, it may be suitable to appl~ a friction-reducing
layer, for example polytetrafluoroeth~lene, to all or portions
of the recess 57 so as to permit a complete extension of the wall
of the region 2, 2' ox 2" o~er the entire hight.
The slightly c`ompressed support air blown into the mold
through the channél 47 is of particular aid in the preforming of
the sprinkler hose in the portion of the mold line shown in Fig.
17. This~ support air results in the flawless attachment of the
walls 17, 18 to the side of the mold. The shape of the dead-space
chambers 14, 14' and their connection with the hose region 2, 2'
or 2" through connecting throttling openings 10 or connecting
channels 25 also serves to transport away any air present in the
hose 45' and thus to prevent bubbles in the finished hose.
It will be appreciated that a particular pair of mold
halves 34, 35' will be configured to produce the bulges 16 for
defining the trickle openings 15 and the initial chambers of the
subsequent cascade with throttle inlet openings 11, 11' and as-
sociated dead space chambers 14, 14'. The length or division t
of a given hose may be altered by appropriate insertion or re-
moval of regular mold halves 34, 35' not having these specialfeatures. If the length or division t of a given sprinkler hose
is so large that the pressure drop within one cascade of chambers
is too high, i.e., the amount of water
- 21 -
~6~
emerging in drops would ~e too low for a given purpose, the
numher of effective chambers having connecting throttle openings
may be reduced by inserting a mold half used for producing
a last chamber having a trickle opening and a first chamber
having an inle-t throttle opening without the recess required
to produce the bulge in which the trickle opening would be
located~ In this manner,there is produced a dead train of
chambers..which are..connected..with the hose region 2 by inlet-
throttles. These and other steps permit the production of
any desired combination of distances between adjacent trickle
openings to produce a given division t and,if necessary,a
smaller pressure drop.
The dimensions and cross sections of particularly
advantageous samples of the embodiments described above,
are given below. In a sprinkler hose of the type 1 and 1":
Cross section of the cylindrical chambers 8, 9 = 2 8 mm2;
'Cross section of the throttle inlet opening 11
=0.3 mm x 2.5 mm = 0.75 mm .
-Cross section of the connecting throttle openings lO
= 0.................................... 5.mm x 3.mm = 1.5 mm .
Sprinkler hose 1':
Cross section of the cylin~rical chambers 8', 24, 9'
= 2.3 mm2;
Cross section of the inlet throttle openings'll' =
~.3 mm x 2 mm = ~.6 mm2.
Cross section of the connecting throttle openings
10' - 0.5 mm x 2 mm = 1 mm2;
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The cross.sections of throttle inlet openinys ll or ll'
can generally be in the range of from 0.4..to l.0 mm .
The cross sections of connecting throttle openings lO,
lO' can generally be in the range of from 0.8 to.2.0 mm2.
In this embodiment of the cross sections, especially of
the connecting throttle openings lO, lO', approximately 40 to
lO0 cylindrical chambers 8, 9 or 8', 24, 91 are required to obtain
: a trickle output of approximately 2 liters/h with a pressure re-
duction of l bar in a throttle region. Given a chamber length
of approximately 15 mm, this will result in a total throttle re-
gion length between 600 and l,500 mm. Depending on the number
of chambers arranged in parallel rows, a distance of 300 mm be-
tween trickle openings should be easily achievable. Compared
with known sprinkler hoses, a considerable shortening of the
throttle region, i.e. the distance between the throttle inlet
opening to the trickle opening, is achieved.
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