US 5,632,938 AGranted

Meltblowing die having presettable air-gap and set-back and method of use thereof

AssigneeAccurate Products Co.

InventorPeter G. Buehning, Sr.

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Abstract

A metblowing die designed to efficiently receive a preassembled die tip assembly is described. The die assembly includes a die body (19) mounted on a meltblowing machine and a replaceable die tip assembly (20). The die tip assembly (20) includes a mounting block (25), to which are mounted a die tip (26) and air knives (27, 28) on opposite sides or the die tip (26). The positions of the air knives (27, 28) are adjustable to set air gap and set back parameters important in proper operation. The die tip assembly (20) is moved into and out of the die body (19) after air knife adjustment permitting adjustment to be made with the die tip assembly (20) off the machine, allowing rapid replacement. The replacement die tip assembly (20) is preheated, permitting replacement while the die body (19) is still hot.

Claims22

Dependent claims

A meltblowing process including the step of replacing a die tip assembly in use with a preadjusted die tip assembly, comprising the steps of:

providing a meltblowing machine, comprising in use:
(i) an elongated die body having a coathanger-shaped polymer flow passage formed therein, an upper inlet end of said coathanger-shaped polymer flow passage being connected to a source of polymer to be meltblown, and a lower discharge end of said coathanger-shaped polymer flow passage forming an elongate polymer flow port in a lower surface of said die body, said die body further having air flow passages disposed on either side of said polymer flow passage, and said die body being adapted to receive heaters for heating said polymer and air, and
(ii) a die tip assembly,
the machine further comprising a replacement die tip assembly, said die tip assembly in use and said replacement die tip assembly each comprising:
(a) an elongated mounting block having an upper surface for mating with and being secured to said lower surface of said die body, such that polymer and air flow passages formed in said mounting block mate with said polymer and air flow passages formed in said die body,
(b) a die tip mounted to the mounting block, having a downwardly extending elongate nosepiece of generally triangular cross-section terminating at an apex, an elongated polymer channel within said die tip,and a plurality of small-diameter polymer orifices extending through said nosepiece into said channel, said polymer channel mating with said polymer passage formed in said mounting block, and
(c) elongated air plates mounted to said mounting block on either side of said die tip by mounting means allowing selection of the position of the air plates with respect to the die tip, defining converging air flow channels between the die tip and the air plates between the nosepiece and the air plates, and setback of the air plates with respect to the apex of the nosepiece said air flow channels mating with said air flow passages formed in said mounting block;
extruding a molten polymer through the orifices of the die tip in use at a meltblowing operating temperature;
preadjusting said replacement die tip assembly, by assembling said replacement die tip and air plates to said replacement mounting block, such that the replacement die tip assembly exhibits desired values for the air-gap and setback;
and
when it is desired to replace the die tip assembly in use with the replacement die tip assembly:
discontinuing the extrusion of the molten polymer;
removing the die tip assembly in use from the die body;
moving the replacement die tip assembly into the position previously occupied by the removed die tip assembly;
and securing said replacement die tip assembly to the die body;
and
recommencing extruding the polymer through the orifices of the die tip of said replacement die tip assembly.

14 more elements

A die assembly for a meltblowing machine comprising:

(a) an elongated die body defining a central coathanger-shaped polymer flow passage and air flow passages on either side thereof, said die body receiving heaters for heating polymer and air flowing in said passages, said die body defining a surface for receiving a mounting block, and said polymer and air flow passages terminating at said surface for mating with corresponding passages defined by said mounting block;
(b) an elongate mounting block adapted to be received by and secured to said surface of said die body such that polymer and air flow passages in said mounting block mate with corresponding passages in said die body;
(c) a die tip adapted to be received by and secured to the mounting block and having an outwardly extending elongate nosepiece of triangular cross-section terminating in an apex, an elongate polymer channel being formed within said nosepiece for communicating with the polymer flow passage in said mounting block, and a plurality of orifices being formed in at least one row along the apex and communicating with said polymer channel;
(d) first and second air knife plates for being secured to the mounting block on opposite sides of the nosepiece and therewith defining converging air passages mating with said air flow passages in said mounting block, said air knife plates being spaced from said nosepiece by air-gaps;
(e) means for adjustably securing the air knife plates to the mounting block, said means for securing permitting adjustment of the air-gaps and set-back of the air knife plates with respect to the apex of the nosepiece;
and
(f) means for clamping the mounting block with the die tip and air knife plates secured thereto to the die body and being releasable to permit the mounting block with the die tip and air knife plates secured thereto to be removed therefrom.

4 more elements

A meltblowing die assembly with a replaceable die tip assembly, said die assembly comprising:

1) a die body having
(a) an elongate cavity formed therein and defined by opposite inwardly facing side walls and a bottom surface,
(b) an elongated coathanger-shaped polymer flow passage discharging through the bottom surface,
(c) first and second air flow passages on either side of said polymer flow passage, and
(d) heating means for heating polymer and air flowing in said passages;
and
(2) a die tip assembly, said die tip assembly comprising:
(a) an elongate mounting block being substantially coextensive with the cavity and having
(i) outwardly facing side walls and an upwardly facing surface,
(ii) a downwardly facing surface,
(iii) a polymer flow passage extending from the upwardly facing surface to the downwardly facing surface, and
(iv) first and second air flow passages extending from the upwardly facing surface to the downwardly facing surface, the mounting block being adapted to be positioned in the die body cavity
(b) an elongate die tip having a triangular, downwardly converging nosepiece terminating in an apex, a row of orifices formed along the apex, an upwardly facing base surface, and a polymer flow passage extending from the base surface to the orifices,
(c) air plates for being mounted on the mounting block on opposite sides of the nosepiece and therewith defining converging air passages, each defining an air gap mating with said first and second air flow passages in said mounting block;
and
(d) means for securing the air plates to the mounting block, said means for securing comprising means for adjusting the relative positions of the air plates with respect to the nosepiece of the die tip, to permit the presetting of the air gap defined by each of the air passages defined between said air plates and said nosepiece and the setback between the air plates and the apex;
(e) means for mounting the die tip on the mounting block, whereby the polymer flow passages of the mounting block and the die tip are secured in fluid communication;
and
(f) means for securing the mounting block to the die body with the die tip and air plates mounted thereon and with the air and polymer flow passages of the die body and mounting block in fluid communication, whereby release of the means for securing permits the mounting block to be secured to or be removed from the die body without disturbing the adjustment of the air plates with respect to the nosepiece.

16 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/284,549Filed 9 Jan 1995 · continuation in part
Priority: 13 Feb 1992
Granted: 27 May 1997
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

D01D 4/025
Spinnerettes: melt-blowing or solution-blowing dies
B29C 48/05
Characterised by the shape of the extruded material at extrusion: filamentary, e.g. strands
B29C 48/08
Flat, e.g. panels: flexible, e.g. films
B29C 48/256
Component parts, details or accessories; Auxiliary operations: exchangeable extruder parts