System for conveying and treating an endless textile loop

An apparatus for treating an endless textile web by passing it in a direction along an endless path and contacting it with a treatment fluid has a conveying nozzle provided with a housing traversed by the path and having a lateral inlet, an upstream tube and downstream tube longitudinally traversed by the path. The upstream tube has an upstream portion of a cross section decreasing in the direction and a downstream portion of substantially constant cross section and having a downstream end. The downstream tube has an upstream portion of a cross section decreasing in the direction and having an upstream end in the housing upstream of the downstream end of the upstream tube, spaced laterally outward from the downstream portion of the upstream tube, and forming with the downstream portion of the upstream tube a gap open into the housing and a downstream portion of cross section increasing in the direction. The web and path extend through the tubes and a blower connected to the inlet pressurizes the housing and induces a gas flow in the direction through the downstream tube to draw the web longitudinally through the tubes along the path.

SPECIFICATION 
1. FIELD OF THE INVENTION 
The present invention relates to a nozzle for conveying an endless textile 
loop. More particularly this invention concerns a system for conveying and 
treating such a loop. 
2. BACKGROUND OF THE INVENTION 
It is known to displace and treat a textile web or strand by means of a 
nozzle of the type described in European 0,172,406 of G. Eckrodt. Such a 
nozzle works on the jet-pump principle, with an upstream tube whose 
downstream end fits with spacing into a flared upstream end of a 
downstream tube. A gas or liquid under pressure is supplied to the gap 
between the tubes to create a downstream flow that entrains the web. The 
conveying medium can even be admixed with a treatment liquid or gas. Such 
a system subjects the workpiece, here the textile web, to considerable 
stress. If the pressure is decreased to avoid harming the web, the 
conveying and saturating efficiency drop substantially, even when as 
suggested an inert gas is used with the treatment liquid. 
German patent 3,245,921 of H. Kreitz describes an entire treatment 
apparatus where the web endless and is laid in folds in one side of an 
upwardly open U-shaped vessel while it is drawn up out of the other side 
of the vessel. A jet-pump nozzle is used to displace the web which is 
still subjected to considerable mechanical action and stress so that this 
system is not applicable, for instance, to delicate fabrics. 
The web is handled somewhat more gently by the system of German patent 
4,119,152 of K. Grafen. A pair of coaxial nested cylindrical tubes form a 
conveying nozzle and the path of the workpiece is fairly simple. The 
conveying nozzle works with a very low efficiency so that the system's 
blower must be fairly big and consumes a great deal of electricity to 
convey the relatively light workpiece. 
A somewhat more efficient conveying nozzle is seen in French patent 
document 2,619,834 of A. Bene. It has a two-stage jet-pump nozzle that is 
quite complex to build and maintain. The upstream portion of circular 
section and the second is more rectangular, of decreasing height and 
increasing width so that it is quite difficult to manufacture. 
OBJECTS OF THE INVENTION 
It is therefore an object of the present invention to provide an improved 
conveying nozzle for a web-treating apparatus. 
Another object is the provision of such an improved conveying nozzle for a 
web-treating apparatus which overcomes the above-given disadvantages, that 
is which is relatively simple in construction, that is highly efficient, 
and that treats the web gently. 
SUMMARY OF THE INVENTION 
An apparatus for treating an endless textile web by passing it in a 
direction along an endless path and contacting it with a treatment fluid 
has a conveying nozzle provided with a housing traversed by the path and 
having a lateral inlet, an upstream tube and downstream tube 
longitudinally traversed by the path. The upstream tube has an upstream 
portion of a cross section decreasing in the direction and a downstream 
portion of substantially constant cross section and having a downstream 
end. The downstream tube has an upstream portion of a cross section 
decreasing in the direction and having an upstream end in the housing 
upstream of the downstream end of the upstream tube, spaced laterally 
outward from the downstream portion of the upstream tube, and forming with 
the downstream portion of the upstream tube a gap open into the housing 
and a downstream portion of cross section increasing in the direction. The 
upstream portion has a downstream end of a cross-sectional size equal to 
between 1.3 and 3 times, preferably between 1.5 and 2.5 times, a 
cross-sectional size of the downstream portion of the upstream tube,The 
web and path extend through the tubes and a blower connected to the inlet 
pressurizes the housing and induces a gas flow in the direction through 
the downstream tube to draw the web longitudinally through the tubes along 
the path. 
The transport gas forced in through the gap or gaps is at its highest speed 
and lowest pressure where it comes into contact with the web, meeting it 
at an inflow angle of from 5.degree. to 20.degree., preferably 5.degree. 
to 15.degree.. The result is extremely efficient entrainment of the web 
since the flow thence is substantially laminar. The downstream portion of 
the downstream end acts as a diffuser, being flared at at most about 
10.degree., so that even here the workpiece is treated very gently, with 
practically no turbulence in the conveying gas. Furthermore since the gas 
is introduce from outside, it is possible to thus treat and convey tubular 
goods, such as many knits, without inflating them and making them hard to 
manage. Such a nozzle can do the same amount of work as that of 
above-cited German 4,119,152 with about half the energy consumption. In 
fact such a nozzle can in principle be used for conveying paper strips, 
metal foils, or even wood products. 
The downstream tube further has an intermediate portion of a substantially 
constant cross section between and connecting the respective upstream and 
downstream portions. The cross sections can be generally rectangular or 
circular. With a rectangular section the upstream end of the downstream 
tube and the downstream end of the upstream tube are of substantially the 
same width and thus form two such gaps open into the housing. 
The housing can be formed as an upstream continuation of the upstream end 
of the downstream tube. This continuation is of a substantially constant 
cross section. 
To ensure proper fan-fold deposition of the web, the nozzle is provided 
with means for oscillating a downstream end of the downstream portion of 
the downstream tube. To reduce the losses created when dynamic pressure is 
converted to static pressure and then back again, the housing is provided 
with quarter-circular guide vanes for directing gas flow from the intake 
to the gap. 
The apparatus according to the invention has a U-shaped receptacle 
traversed by the path underneath the nozzle, treatment means for applying 
the fluid to the web between the downstream tube and the receptacle, and 
means for collecting the treatment fluid and returning it to the treatment 
means.

SPECIFIC DESCRIPTION 
As seen in FIG. 1 a nozzle for conveying a web 1 according to the invention 
has relative to a web-travel direction 6 an upstream housing 2 formed with 
a lateral inlet 5 and forming a plenum 13 longitudinally traversed by the 
web 1. Inside the housing 2 is an upstream tube 3 having an upstream 
portion 7 that tapers downstream and a downstream portion 8 that is of 
constant cross-sectional size and shape. A downstream tube 4 has an 
upstream end 9 that projects into the housing 2 and that has an upstream 
end that is level with or upstream in the direction 6 from the downstream 
end of the tube portion 8, and that in fact lies at the juncture of the 
portion 7 and 8, an intermediate portion 10 of constant cross section, and 
a downstream portion 11 that flares downstream as a diffuser. The portions 
7, 9, and 11 are substantially frustoconical and coaxial to an axis A and 
the portions 10 and 8 are substantially cylindrical and also coaxial to 
the axis A. The portion 9 lies partly inside and partly outside the 
housing 2 and the portions 10 and 11 are wholly outside the housing 2. The 
flow cross section or cross-sectional size of the portion 9 at its 
downstream end, that is where it joins the poriton 10 and where it is at 
its narrowest, is equal to between 1.5 and 2.5 times, here 2 times, the 
flow cross section of the cylindrically tubular portion 8. 
A blower indicated schematically at 31 pressurizes the plenum 13. This 
pressurized air enters a gap 12 formed between the portions 8 and 9 and 
flows downstream, entraining the web 1 in the direction 6. The air rushing 
downstream in direction 6 with the web 1 compacts it at an angle of 
between 5.degree. and 20.degree., preferably 5.degree. to 15.degree., 
transversely to keep it out of contact with the inner wall surfaces of the 
tubes 3 and 4. The air is normally moving at 100 m/s and can approach the 
speed of sound or 140 m/sec. This air speed slows in the diffuser portion 
11 so that the web 1 exits the downstream end of the downstream portion 11 
gently. 
The angle of the wall of the first portion 9 is 10.degree. to 40.degree., 
preferably 10.degree. to 30.degree., while that of the portion 11 is at 
most about 10.degree. to the axis A. The width of the gap perpendicular to 
the axis A is roughly the same size as the spacing along the axis A from 
the downstream end of the portion 8 to the upstream end of portion 10. The 
cross-sectional area of the portion 10 is equal to that of the downstream 
end of the portion 9 and about twice that of the portion 8 and the 
cross-sectional area of the downstream portion 11 increases by two to ten 
times, preferably three times. The length of the downstream portion 8 is 
roughly a quarter the length of the portion 7 and about half the axial 
length of the portion 8. Furthermore the length of the nozzle from the 
downstream end of the portion 7 to the downstream end of the portion 9 is 
about equal to the length of the portion 10 and is equal to about a third 
of the length of the portion 11. 
FIGS. 2 and 3 show another embodiment of the invention. Here an upstream 
housing 2' formed with a lateral inlet 22 contains an upstream tube 3' 
having an upstream portion 7' that tapers downstream and a downstream 
portion 8' that is of constant cross-sectional size and shape. A 
downstream tube 4' has an upstream end 9' that forms the downstream end of 
the housing 2', an intermediate portion 10' of generally constant cross 
section, and a downstream portion 11' that flares downstream as a 
diffuser, the height of the portion 11' increasing only slightly but the 
width increasing by a factor of 1.5. The side walls of the portion 11 
extend at about 9.degree. to the direction 6 and the overall cross section 
increases by a factor of three. 
The housing 2' and tubes 3' and 4' are of rectangular section and are of 
roughly the same horizontal width as seen in the FIG. 3 top view but are 
of different heights as is visible in the FIG. 2 side view so as to create 
two gaps 12' above and below the upstream tube 3', the ratio of width to 
height being 2:1 to 4:1. The upper and lower walls of the portion 9' 
extend at about 20.degree. to the transport direction 6. Above and below 
the upstream tube 3' the housing 2' is provided internally with three 
quarter-circular vanes or baffles 21 that redirect the air flow from the 
lateral outlet so that it flows downstream in direction 6. In addition the 
upstream end of the upstream tube 3' is provided with a collar 23 that 
flares upstream and that prevents the web 1 from getting caught as it 
enters the nozzle. The inlet 22 is formed as a wedge with its one wide 
side extending over the side wall of the portion 7 and extending in the 
transport plane, pointing perpendicular outward from the direction 6. 
Normally the housing 2', upstream tube 3', and downstream tube 4' are made 
of welded stainless-steel plates or sheet metal. The corners, in 
particular those of the diffuser 11', can be rounded. 
The intermediate portion 10' is formed by a downstream section 17 and a 
slightly smaller upstream section 18 interconnected at a vertical pivot 19 
with an overlap at 20. The heights of the portions 17 and 18 in the 
overlap region 20 are only different basically by an amount equal to twice 
the wall thickness but the width of the downstream portion 17 is greater 
by 10% to 20% from that of the portion 18 to accommodate swinging about an 
axis A'. A motor illustrated schematically at 32 can be connected to the 
portions 11' and 17 to oscillate them back and forth about the axis A' 
perpendicular to the direction 6 to lay the exiting web 1 in fan folds. 
FIG. 4 shows a system of the type generally described in above-mentioned 
French patent 2,619,834 and German patent document 195 17 298, 3,245,921, 
and 4,119,152. It has a main basically cylindrical housing 24 provided 
with a lateral access/loading port 25 and holding an upwardly U-shaped 
treatment vessel 26. A nozzle as described above with reference to FIGS. 2 
and 3 is mounted above the vessel 26 and has its intake 22 connected to an 
outlet 37 of a fan 36 powered by a motor 35 sitting atop the housing 26. 
The fan 36 is of the axial-intake/radial output type with the intake in 
the housing 24. 
The web 1 passes in a continuous annular path through the vessel 26 and 
then up through a guide ring 29 and over an idler/deflecting roller 30 to 
enter the upstream end of the nozzle. On exiting the nozzle the web enters 
an upstream end 39 of the vessel 26 where it is sprayed from a treatment 
nozzle 27 that is supplied dye liquid from a pump 28 whose intake is at a 
sump 34 in the bottom of the housing 24 and vessel 26. 
While this device is normally used for dying textile lots, it can also be 
used for an enzyme treatment or even a dry tumbling treatment of the web 
1.