Conformal coating applicator and method

Patent metadata

Field	Value
Publication number	US-9346074-B2
Application number	US-88058810-A
Country	US
Kind code	B2
Filing date	Sep 13, 2010
Priority date	Sep 13, 2010
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

An applicator for dispensing a liquid conformal coating material onto a substrate. The applicator includes a body assembly with a liquid flow passage having a liquid inlet adapted to receive the coating material and a liquid outlet. A valve seat is positioned between the liquid flow passage and the liquid outlet. A valve stem is mounted in the body assembly for reciprocating movement between an open position and a closed position. The valve stem includes a first end and a second end. The first end of the valve stem engages the valve seat in the closed position to stop flow of the liquid coating material through the outlet and disengages from the valve seat in the open position to allow flow of the liquid coating material through the outlet. A valve actuating mechanism is operative to move the valve stem from the open position to the closed position and is further operative to move the valve stem from the closed position to the open position. A resilient dampening element is operatively coupled between part of the body assembly and the valve stem. The resilient dampening element provides a biasing force against the valve stem as the valve stem moves from the closed position to the open position to reduce rebounding movement of the valve stem toward the closed position.

First claim

What is claimed is:

1. An applicator for dispensing a liquid conformal coating material onto a substrate, the applicator comprising:
a body assembly including
i. a liquid flow passage having a liquid inlet adapted to receive the coating material, and a liquid outlet;
ii. a valve seat positioned between the liquid flow passage and the liquid outlet; and
iii. a valve actuating mechanism;

a valve stem mounted in the body assembly for reciprocating movement between an open position and a closed position, the valve stem including a first end and a second end, the first end of the valve stem engaging the valve seat in the closed position to stop flow of the liquid coating material through the outlet, and disengaging from the valve seat in the open position to allow flow of the liquid coating material through the outlet, wherein the valve actuating mechanism is operative to move the valve stem from the open position to the closed position and is further operative to move the valve stem from the closed position to the open position;
a valve stroke adjuster with a stop element for adjusting the distance that the valve stem travels between the open and closed positions; and
a resilient dampening element located between the stop element and the valve stem, the resilient dampening element providing a biasing force against the valve stem as the valve stem moves from the closed position to the open position, wherein the resilient dampening element contacts the valve stem in the open and closed positions as well as during movement of the valve stem between the open and closed positions.

2. The applicator of claim 1 , wherein the resilient dampening element further comprises an elastomeric material.

3. The applicator of claim 1 , wherein the valve stem further comprises an assembly having a piston, the piston positioned in a piston chamber configured to receive pressurized air at least on one side of the piston for moving the piston and the valve stem to the open position.

4. The applicator of claim 3 , wherein the valve actuating mechanism further comprises a spring return mechanism having a spring that exerts a spring force on the valve stem, the spring return mechanism being operative to move the valve stem from the open position to the closed position when pressurized air is vented from the piston chamber.

5. The applicator of claim 4 , wherein the spring is a coil spring and the resilient dampening element is located within the coil spring.

6. The applicator of claim 1 , wherein a gap exists between the resilient dampening element and the stop element when the valve stem is in the closed position.

7. An applicator for dispensing a liquid conformal coating material onto a substrate, the applicator comprising:
a body assembly including
i. a liquid flow passage having a liquid inlet adapted to receive the coating material, and a liquid outlet;
ii. a valve seat positioned between the liquid flow passage and the liquid outlet;
iii. a valve actuating mechanism;

a valve stem mounted in the body assembly for reciprocating movement between an open position and a closed position, the valve stem including a first end and a second end, the first end of the valve stem engaging the valve seat in the closed position to stop flow of the liquid coating material through the outlet, and disengaging from the valve seat in the open position to allow flow of the liquid coating material through the outlet, wherein the valve actuating mechanism is operative to move the valve stem from the open position to the closed position and is further operative to move the valve stem from the closed position to the open position;
a valve stroke adjuster with a stop element for adjusting the distance that the valve stem travels between the open and closed positions; and
a resilient dampening element formed from a resilient, elastomeric material and mounted at the second end of the valve stem, the resilient dampening element providing a biasing force against the valve stem as the valve stem moves from the closed position to the open position, wherein the resilient dampening element contacts the valve stem in the open and closed positions as well as during movement of the valve stem between the open and closed positions.

8. A method of dispensing a liquid conformal coating from an applicator having a valve stem, and providing sharper dispensed liquid patterns by reducing bounce back of the valve stem upon opening, comprising:
supplying pressurized liquid conformal coating material to a liquid flow passage of an applicator;
moving a valve stem along a stroke length defined between a closed position in which the valve stem is engaged with a valve seat to prevent the flow of the liquid conformal coating material from the liquid flow passage to an outlet of the applicator, and an open position defined by a valve stroke adjuster with a stop element wherein the valve stem is disengaged from the valve seat to allow the liquid conformal coating material to flow from the liquid flow passage to an outlet and produce a conformal coating pattern on a substrate; and
compressing a resilient, elastomeric element between the valve stem and the stop element as the valve stem moves towards the open position; and
maintaining contact between the resilient, elastomeric element and the valve stem in the open and closed positions as well as during movement of the valve stem along the stroke length between the open and closed positions.

9. The method of claim 8 , further comprising:
moving the valve stem to the closed position with a spring return mechanism.

10. The method of claim 8 , further comprising:
when the valve stem is in the closed position, forming a gap between the resilient, elastomeric element and the stop element.

Assignees

• Hogan Patrick T
• Tedrow Jon
• Nordson Corp

Inventors

• Hogan Patrick T
• Tedrow Jon

Classifications

• B05C11/1028

  Lift valves · CPC title

• B05C5/0225 Primary

  characterised by flow controlling means, e.g. valves, located proximate the outlet (B05C5/0258, B05C5/0275 take precedence; supply valves upstream the coating head B05C11/1036) · CPC title

• B05B1/306

  the actuating means being a fluid · CPC title

• B05B1/32

  in which a valve member forms part of the outlet opening {(B05B1/3033 takes precedence)} · CPC title

• B05B7/12 Primary

  designed to control volume of flow, e.g. with adjustable passages · CPC title