Plastic and nonmetallic article shaping or treating: processes – Forming continuous or indefinite length work – Shaping by extrusion
Patent
1992-03-24
1994-02-15
Thurlow, Jeffery
Plastic and nonmetallic article shaping or treating: processes
Forming continuous or indefinite length work
Shaping by extrusion
137 98, 251 5, 264 407, 264240, 2643286, 264349, 425145, 4253761, B29C 4712, B05B 1200, B05B 1500
Patent
active
052864332
DESCRIPTION:
BRIEF SUMMARY
The present invention refers to a method and a device to pressure balance hoses at supply of two different components with substantially the same pressure to an extrusion head, where the flow of the second component is substantially below the flow of the first component, e.g. at thermosetting plastic extrusion.
BACKGROUND OF THE INVENTION
The dosing and forward feeding of the components is commonly carried out by means of piston pumps, which causes the hoses to enter into a self oscillating state at the forward and reverse action of the pump piston. A remaining pulsation is obtained which leads to an exact dosing being impossible, particularly if the dosing quantity is very small, which is the case e.g. at thermosetting plastic extrusion, where the setting agent only constitutes about 1-4 volume-%. Even at shut-off the extrusion head the hose is somewhat extended, which contributes to incorrect dosing.
SUMMARY OF THE INVENTION
The object of the invention is to avoid the above stated problem and provide a method stated by way of introduction, which means that pressure changes in the supply hoses does not influence the flow ratio between the components. This has been solved by letting at least during a part of the path to the extrusion head the pressure from the first component act on the second component and by supplying the second component in a second hose which during at least one part of the path to the extrusion head extends inside a first hose in which the first component is supplied.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described more in detail with reference to an embodiment shown in the accompanying drawing.
FIG. 1 is a diagrammatic explanatory outline of a device according to the invention.
FIG. 2 is a section through a part of the pressure balanced hose corresponding to encircled part in FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the drawing the reference numbers 10 and 11 designate two hoses for supply of a first and a second component, e.g. plastic and setting agent, to a mixing chamber 12 to an extrusion head. The components fed forward with substantially the same pressure P.sub.1A .apprxeq.P.sub.1B by means of pumps 14 and 15 e.g. piston pumps. The flow of the second component substantially decreases the flow of the first component.
The second hose 11 is via a branch pipe 16 conducted into the first hose 10 and then extends inside the first hose 10 over a substantial part of its length before the components are mixed in the mixing chamber 12. The pressure P.sub.2 in this is essentially the same as in the hoses 10 and 11.
Since P.sub.1A .apprxeq.P.sub.2B, that is the same pressure on the out and inside of the second hose 11, this will not extend at pressure variations in the forward feeding. The flow fed forward of the second component will be substantially constant in time.
Pressure changes, e.g. in connection with the piston movements or at shut-off of the extrusion head, thus will not influence the flow ratio between the first and the second component.
The invention is of course not limited to thermosetting plastic extrusion but can be applied in other connections where two components are extruded, whereby the flow of one of the components is less than the flow of the second component.
1. A method to pressure balance hoses during supply of two different components with substantially the same pressure to an extrusion head, where the flow of the second component is substantially below the flow of the first component, comprising the steps of: the first component acts for at least a part of the path to the extrusion head.
2. A device for pressure balancing hoses during supply of two different components with substantially the same pressure to an extrusion head, where the flow of the second component is substantially below the flow of the first component comprising: a second component to the extrusion head and arranged for pressure actuation of the second component.
3. The device according to claim 2, including a branch pipe for connecting said sec
REFERENCES:
patent: 676366 (1901-06-01), Koch et al.
patent: 2584226 (1952-02-01), Pool
patent: 2598307 (1952-05-01), Rutgers
patent: 3154618 (1964-10-01), Baer et al.
patent: 3701618 (1972-10-01), Wall et al.
patent: 3761213 (1973-09-01), Wight
patent: 4309373 (1982-01-01), Althausen et al.
patent: 4368219 (1983-01-01), Nagata et al.
patent: 4848387 (1989-07-01), Hon
patent: 5125819 (1992-06-01), Hager et al.
Applicator System AB
Thurlow Jeffery
Vargot Mathieu
LandOfFree
Method and device for pressure balancing of hoses at extruding o does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for pressure balancing of hoses at extruding o, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for pressure balancing of hoses at extruding o will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1204676