U.S. patent number 3,905,381 [Application Number 05/395,036] was granted by the patent office on 1975-09-16 for filament liquid quenching apparatus.
This patent grant is currently assigned to Phillips Petroleum Company. Invention is credited to Richard D. Meyer.
United States Patent |
3,905,381 |
Meyer |
September 16, 1975 |
Filament liquid quenching apparatus
Abstract
Melt-spun thermoplastic filaments are liquid quenched in an
apparatus equipped with baffles for quieting the surface of said
quenching liquid and a weir for maintaining a constant level of
quenching liquid. The liquid is removed from said filaments by an
apparatus containing an enclosed chamber which is partially defined
by a perforated surface over which said filaments pass in contact
therewith, said chamber being in communication with means for
removing fluids therefrom.
Inventors: |
Meyer; Richard D. (Greenville,
SC) |
Assignee: |
Phillips Petroleum Company
(Bartlesville, OK)
|
Family
ID: |
23561441 |
Appl.
No.: |
05/395,036 |
Filed: |
September 7, 1973 |
Current U.S.
Class: |
134/122R;
15/309.1; 425/71; 15/302; 264/178F |
Current CPC
Class: |
D01D
5/0885 (20130101); D01D 10/0436 (20130101) |
Current International
Class: |
D01D
5/088 (20060101); D01D 10/04 (20060101); D01D
10/00 (20060101); B08B 003/00 (); B29D 023/06 ();
B29C 025/00 () |
Field of
Search: |
;134/64,122 ;425/71,68
;15/302,36A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hornsby; Harvey C.
Assistant Examiner: Moore; C. K.
Claims
What is claimed is:
1. Apparatus for liquid quenching melt-spun thermoplastic filaments
comprising:
a tank for storing a quench liquid;
at least one baffle in said quench tank to dampen the movement of
quench liquid wherein said baffle contains an opening through which
said filaments pass and a perforated area to permit circulation of
said quench liquid but which reduces turbulence of said quench
liquid;
a means for guiding said filaments through said tank; and
a weir to control the level of quench liquid in said tank.
2. The apparatus of claim 1 wherein at least two baffles are
provided and the perforations in said baffles are progressively
smaller in baffles progressively nearer to the area where the
filaments enter the quench liquid.
3. The apparatus of claim 2 wherein said weir is located in a
quiescent area of the tank.
4. The apparatus to claim 3 wherein the weir is adjustable in order
to raise or lower the level of the quench liquid in the tank.
5. The apparatus of claim 3 wherein said weir has a vertical
cylindrical wall and has notches in the upper rim of the wall in
the range of 1/16 to 1/2 inch wide, 1/16 to 1/2 inch deep and 1/2
to 3 inches apart.
Description
BACKGROUND OF THE INVENTION
The invention relates to an apparatus for liquid quenching
melt-spun thermoplastic filaments and an apparatus for removing the
quenching liquid from the quenched filaments.
In liquid quenching melt-spun thermoplastic filaments it is
desirable that the surface of the quenching liquid be in a
quiescent state in the area where the freshly spun filaments enter
the liquid. Normally, the primary cause of turbulence in the quench
tank is not the filaments entering the liquid, but rather the
passage of the filaments through the tank and particularly the
filaments leaving the liquid. The area where the filaments leave
the liquid is usually at the opposite end of the quench tank from
where the filaments enter the liquid. However, the turbulence
generated by the filaments moving through the tank and leaving the
liquid causes waves on the surface of the liquid which travel to
the area where the filaments enter the liquid. These waves can
splash upon the hot spinning apparatus or spinnerets adversely
affecting the uniformity of the filaments and damaging the
spinnerets. Also the filaments themselves can be deformed by the
direct action of the waves upon them during the quenching process
causing irregular drawing of the filaments or the unquenched
filaments to fuse together. Consequently to produce uniform liquid
quenched filaments it is desirable to maintain the surface of the
quenching liquid in a quiescent state.
In addition to problems caused by waves, other problems exist in
liquid quenching systems. For example, fluctuation in level of
quenching liquid in the quench tank affects the uniformity of the
filaments. To reduce this problem the level of quenching liquid is
often maintained by using a weir, but due to the meniscus action of
most quenching liquids, there is some fluctuation in the quenching
liquid level even though a weir is used.
Another problem encountered in liquid quenching systems is removing
the liquid from the filaments after the filaments have been
quenched. A number of methods have been developed to remove the
quench liquid from the filaments, but frequently they abrade, cut
or otherwise damage the filaments or affect their uniformity.
It is an object of the invention to provide apparatus to liquid
quench melt-spun thermoplastic filaments.
Another object of the invention is to provide a quench tank with a
quiescent liquid surface.
Still another object of the invention is to provide a quench tank
with a weir which minimizes the meniscus effect of the quenching
liquid on the level of quenching liquid in the tank.
Yet another object of the invention is an apparatus for removing
quenching liquid from the filaments without damaging or affecting
the uniformity of the yarn.
SUMMARY OF THE INVENTION
In accordance with the invention there is provided apparatus for
liquid quenching melt-spun thermoplastic filaments comprising, in
combination: a quench tank containing baffles to calm the quench
liquid; a weir located in a quiescent area to minimize the meniscus
action of the quench liquid and to maintain a constant liquid level
of quench liquid in the quench tank; and an apparatus for removing
the quench liquid from the filaments.
Further according to the invention there is provided an assembly
useful for removing liquid from the filaments comprising, in
combination: a chamber which contains perforations in a surface
over which filaments pass in contact therewith and a means in
communication with said chamber for removing fluids therefrom.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diametric view, partly cut away, of a combined
apparatus in accordance with the invention.
FIG. 2 is a sectional view of the quench tank of FIG. 1 showing the
baffles and the path of the filaments through the quench tank.
FIGS. 3, 4 and 5 are elevation views of the baffles of FIGS. 1 and
2 showing cutouts for the filaments and perforated areas for quench
liquid circulation.
FIG. 6 is an elevation, partly cut away, of the weir of FIG. 1.
FIG. 7 is a diametric view, partly cut away, of apparatus used to
remove the quench liquid from the filaments.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings wherein like reference numerals are
employed to denote like elements, the invention will be more fully
explained. FIG. 1 illustrates a combination of the invention
wherein thermoplastic filaments 2 are extruded through spinnerets
1. As the filaments 2 leave the surface of the spinnerets 1, they
pass through air for a distance 3 or some other gaseous atmosphere
prior to entering the quench liquid. Since the quench liquid is
normally considerably cooler than the temperature of the spinnerets
1, the quench liquid must not contact the spinnerets or damage to
the spinnerets may result. The filaments 2 then pass into the
quench liquid 4 at point 6. The filaments 2 pass through the liquid
over a guide means 8 through slots 10, 12 and 14 in the baffles 16,
18 and 20 respectively. The filaments 2 pass out of the quench
liquid 4 at point 22 and through quench liquid removal means
generally denoted by reference numeral 24 and onto further
processing.
The quench liquid 4 is contained in a tank, generally denoted by
reference numeral 26. The tank 26 is equipped with a weir,
generally denoted by reference numeral 28 to control the level of
quench liquid in the tank within a narrow range. Quench liquid
enters the tank through conduit 36 and perforated conduit 37 and
exits the tank through opening 38 after it spills into weir pot 40.
A baffle 39 is provided above perforated conduit 37 to minimize
turbulence due to the incoming quench liquid. The liquid 4 can be
recirculated and conditioned if desired or it can be discarded
after it passes through the tank. Frequently where water is used as
the quenching liquid, tap water is fed to the tank and discarded
after passing through outlet 38. The liquid 4 can pass freely
through the perforated sections 30, 32 and 34 in baffles 16, 18 and
20 respectively.
FIG. 2 illustrates the path of filaments 2 through the liquid 4.
The distance the filaments travel from the surface of the
spinnerets to the quench liquid, denoted by numeral 3, varies with
the particular process, but it is usually in the range of from 1/16
to 21/2 inches.
As shown in FIG. 3, opening 10 is large enough for the filaments to
pass through it without touching the baffle. The perforated section
30 is located in the lower portion of the baffle 16b. The apertures
42 therein and the perforated section itself 30 are of sufficient
size to permit adequate circulation but minimize turbulence of the
quench liquid. It is within the scope of the invention that the
entire baffle be perforated and also that the perforated section be
constructed such that it is removable so that a new perforated
section with different size apertures can be installed. It is
suggested that the tank 26 be constructed such that baffles 16, 18
and 20 are removable. In addition for most convenient operation,
the lower portion of baffles 16, 18 and 20 designated by reference
numerals 16b, 18b and 20b respectively can be separable from the
upper portion of said baffles designated by reference numerals 16b,
18a and 20a respectively. This allows for simplification during
startup in that the upper portion of said baffles are removed until
the line is in operation, thus eliminating the need to thread the
filaments through the holes in the baffles. Although successful
results have been obtained using three baffles in the tank, it is
understood that the invention is not limited to three baffles. The
baffles are used to produce a calm surface in the area where the
filaments enter the quench liquid, reference numeral 6, and
depending on the particular quench liquid, lineal speed of the
filaments etc., one or more baffles may be required.
As shown in FIG. 4, baffle 18 is nearly identical to baffle 16
except that the opening 12 for the filaments is located nearer the
surface of the quench liquid. The perforated section 32 and the
apertures 42 therein are of sufficient size to permit circulation
but to minimize turbulence of the quench liquid.
As shown in FIG. 5, filament opening 14 of baffle 20 is
progressively nearer the surface of the quench liquid as compared
with baffles 16 and 18. The perforated section 34 with the
apertures 42 therein are of sufficient size to permit circulation
but to minimize turbulence of the quench liquid.
The apertures in baffles 16, 18 and 20 are normally smaller in size
the nearer the baffle is to the spinnerets 1. This tends to dampen
the movement of the quench liquid 4 through the tank 26. Also
deepening the tank in the area where the filaments leave the quench
liquid 22 tends to dampen the movement of the quench liquid through
the tank. In fact, it may be possible to remove all but one baffle
nearest the spinnerets 1, if the tank is large enough. Normally,
however, plant space is limited and relatively small tanks are
required, thus making it desirable to use two or more baffles.
Referring to FIG. 6, to minimize the meniscus action of the quench
liquid, notches 44 are cut into the upper rim of the weir. It is
preferred to mill the notches for uniformity and thus better
control of the liquid level in the tank. It is desirable to
construct the weir in such a manner that it can be raised or
lowered to adjust the liquid level in the tank and thus vary the
distance of the liquid from the spinneret. One such method is to
construct the weir standpipe 46 in two sections. The upper section
46a is threaded inside and the lower section 46b is threaded
outside in order to receive the upper section 46a. It is important
to insure that the weir is level for proper weir action. The weir
notches 44 can vary widely in width, depth, shape and distance
apart, but generally they are in the range of 1/16 to 1/2 inch
wide, 1/16 to 1/2 inch deep, "v" or "u" shaped and 1/2 to 3 inches
apart. The weir should be placed in the most quiescent section of
the tank; in FIG. 1 that would be in the area nearest the
spinnerets 1. Also another suitable location for the weir is
between baffles 16 and 18. The weir can be constructed in any
suitable shape; however, the round shape minimizes the creation of
turbulence in the quiescent zone during adjustment of the weir
height, when such adjustment is made by turning the weir.
Referring to FIG. 7, the filament quench liquid removal means
comprises a chamber 48 having apertures 50 located in the upper
portion 52. It is recommended that the apertures 50 be located so
that they cover the entire width of the upper portion 52 in order
that all of the filaments will pass over at least some of the
holes. The chamber 48 is provided with openings 54 for connection
to a vacuum means (not shown) for removing quench liquid, air or
other fluids from chamber 48. The size of apertures 50 are normally
in the range of from 1/64 to 1/8 inch in diameter and 1/8 to 1/2
inch spaced apart. The apparatus 24 can be tapered from the inlet
56 to the outlet 58 to conform the upper portion 52 to the shape of
the filament tow passing over said portion. Also inlet guides 60
are provided at the inlet 56 of said apparatus.
EXAMPLE
Polypropylene filaments were melt-spun through two spinneret heads
and water quenched using an apparatus according to the
invention.
The quench tank was 581/2 inches long and 34 inches wide. The depth
of the tank was 30 inches for a distance of 371/2 inches measured
from the spinneret end and then the bottom was sloped upward
40.degree. from horizontal. The tank at the sloped end had a
minimum depth of 12 inches.
In general, the greater the volume of quench liquid in the tank,
less turbulence is transmitted and thus fewer baffles are required.
The above apparatus was constructed with a sloping bottom due to
space limitation and it was not the preferred design.
The baffles corresponding to baffles 20, 18 and 16 of FIG. 2 were
spaced 15, 26 and 38 inches, respectively, measured from the end
where the filaments leave the quench liquid. The baffle
corresponding to baffle 20 was 333/4 inches wide and 25 inches
deep. The perforated area was 293/4 inches wide, 12 inches deep,
centered on the baffle 2 inches from the bottom and had 0.250 inch
holes on 5/16 inch centers providing 58 percent open area. The tow
opening was 14 inches wide, 21/2 inches deep and centered on the
baffle 21/2 inches from the top.
The baffle corresponding to baffle 18 was 333/4 inches wide and 30
inches deep. The perforated area was 293/4 inches wide, 12 inches
deep, centered on the baffle 2 inches from the bottom and had 0.125
inch holes on 3/16 inch centers providing 40 percent open area. The
tow opening was 18 inches wide, 3 inches deep and centered on the
baffle 7 inches from the top.
The baffle corresponding to baffle 16 was 333/4 inches wide and 30
inch deep. The perforated area was 293/4 inches wide, 10 inches
deep, centered on the baffle 2 inches from the bottom and had 169
0.045 inch holes per square inch providing 27 percent open area.
The tow opening was 24 inches wide, 4 inches deep and centered on
the baffle 12 inches from the top.
The weir was 6 inches inside diameter with 1/4 inch deep notches
spaced 2 inches around the top. The weir was positioned between
baffles corresponding to baffles 16 and 18 of FIG. 2.
The quench liquid removal means comprised two troughs as
illustrated in FIGS. 1 and 7. Each trough had an inlet width of 3
inches and tapered to 1 inch at the outlet end. The holes in the
bottom plates were 1/16 inch in diameter and as close as
possible.
The quench liquid was water and the bath temperature was maintained
at approximately 116.degree.F. The spinnerets were operated at a
distance of between 13/8 inches to 1/16 inch from the surface of
the quench liquid. The vacuum on the quench liquid removal means
varied between 3 to 5 inches of water. The tow denier for both
spinnerets was 438,000 with a line speed of from 266 to 300 feet
per minute.
The above-described apparatus provided a quiescent quench liquid
surface in the area of the spinnerets to the extent that the
spinnerets could be operated continuously within 1/16 of an inch of
the quench liquid. Also it is noted that in the area where the
filaments were leaving the quench liquid, waves over 1 inch were
being produced. In addition the filaments leaving the quench liquid
removal means were not cut or damaged and were dry to the
touch.
* * * * *