IRRADIATOR

Specially designed irradiators for each size lamp are available from Hanovia. These irradiators, when used with the recommended cooling, maintain optimum operatin temperatures on the lamp envelope, end seals and sockets. The irradiator is a lamp housing-reflector assembly.
Its functions are to
(a) support the lamp above the substrate,
(b) reflect the UV energy in a pattern best suited for fast curing, and
(c) facilitate cooling of lamp seals and sockets.
these irradiators consist of a stainless steel housing containing a linear reflector with an elliptical cross section and either sockets (for lamps with metal end fittings)or threaded studs (for lamps with lead wires).
The lamp is held in the reflector so that the arc is in one focal point of the ellipse. This allows the irradiator to be mounted so that the curing surface is in the other focal point. This creates a highly concentrated band of UV energy approximately 3/8" wide and equal in length to the arc gap of the lamp.

In order that the lamp operates properly, it must operate at a rather high temperature (600° to 800กษ on the envelope). However, the end seals must be kept cool (250° to 300กษ maximum). Operating the seals above this temperature could cause the molybdenum foils to oxidize and the seals to fracture. The high operating temperature would tarnish and warp an ordinary fixture. The stainless steel irradiator housing is designed to form an air cooling plenum. This serves to cool the seals and the reflector without over-cooling the lamp body. The reflector attached to this housing is made of specially-processed aluminum which has both high UV reflective (about 90%) and resistance to tarnishing and corrosion far surpassing ordinary aluminum.

The UV Curing Process

UV Curing is a photochemical process by which monomers harden or cure (polymerize or cross-ink) upon exposure to ultraviolet radiation. A specificaly formulated monomer will polymerize when exposed to ultraviolet light. This UV "curable" monomer includes a sensitizer which absorbs UV energy and initiates a polymerizing reaction in the monomer.

The Harnovia System

A complete Hanovia UV Curing System consists of four components

1. The ultraviolet source (a lamp)

2. Irradiator/lamp housing and reflector assembly

3. Power Supply and electrical controls

4. Shielding, cooling and safety equipment.

Hanovia engineers and supplies each of these components as individual units, or as a complete system. Every Hanovia UV Curing System is designed, engineered and built to meet the specific requirements characteristic to your application.

The Ultraviolet Source

The best available UV Source is the high-intensity, medium-pressure mercury vapor lamp.
These lamps are rich sources of 200-400 nanometer ultraviolet radiation. In addition to high efficiency, Hanovia's UV lamps are characterized by long-life and maintenance-free operation.
Lamps are available in operating power levels from 1200 watts to 19,500 watts, and arc lengths form 6" ot 77" at 200watts per linear inch, and from 6" to 65" at 300 watts per linear inch.
In addition to the mercury lamps, Hanovia has available a line of specially doped spectrally-enhanced metal halide lamps.

Application

Ultraviolet curing finds many applications in industries such as printing, metal decorating, and automovie, to name a few. While each industry is unique, they share a common concern-efficient and effective curing of UV sensitive materials.

Hanovia's UV technology provides many advantages compared with other drying procedres.
The foremost is instant, uniform curing which allows for immediate processing and fast turn-around.
That means post press operations can be performed immediately, reducing work in process storage,
and thus improving productivity and profit. And, Hanovia's UV technology helps you produce eye-appearing products that are economically competitive with other forms of curing and protection.
Your product will bave increased life and dependability because substrates cured with Hanovia's UV systems exceed most specifications for rub and wear resistance.

The Irradiator

The design of a Hanovia irradiator allows cooling of the work surface, lamp seals, sockets and reflector without over cooling the lamp. The irradiator is a lamp/housing reflector assembly. It supports the lamp above the substrate and reflects the UV energy in an efficient curing pattern.

Each Hanovia irradiator consists of a stainless steel housing containing a linear reflector with an elliptical cross section. The lamp arc is in one focal point of the ellipse.
For optimum utilization of the reflected UV energy, the irradiator should be mounted so that the substrate is the other focal point. In some applications it is necessary to block the UV from the surface of the substrate during web stoppages.
Hanovia utilizes both a shuttered or turning arrangement for this purpose. Your application will ultimately determine which method is best.

Power Supply and Electrical Controls

A special elctrical system must be used operate the mercury lamp which requires high voltage to initiate the arc and lower voltage to sustain it during operation.

Also required is a current-limiting device to prevent excessive current during the "warm-up" period.
In order to get uniform curing, Hanovia stabilizes the ballast to provide constant power to the lamp even with fluctuations in the line voltage. The result is uniformed curing

Ballasts are available for operation with the complete line of Hanovia 200W/inch and 300W/inch lamps.
Options include unencased ballasts (user supplies switching controls) and encased ballasts with a steel housing, switches and controls for all lamp functions.

In multiple-lamp operations. it may be convenient to remotely locate the ballasts and operate the lamps through control stations near the curing line. Control stations are availbe from Hanovia, and includes all necessary controls for complete systems operation.

Shielding, Cooling and Safety Equipment

Careful consideration must be given to adequate cooling and shielding in order to insure safe and proper equipment performance.
Hanovia builds its lamp housings so that no UV light may be seen from the outside, and connects the
irradiators to an exhaust system in order to cool the reflector and lamp sockets.

 to be continued....