Deciding on a Dryer

After a press, a dryer is one of the most important equipment purchases you’ll make. The right dryer can have a major impact on quality, output, efficiency, and your overall bottom line. Therefore, it makes sense to invest some time considering your needs and the options for filling them.

Quality and volume, present or planned, typically drive the decision to buy a dryer. While it is possible to properly cure prints with spot dryers, a conveyor dryer is faster. You might be able to cure 36 prints an hour with an automatic flash-cure unit, but that’s still not as fast as you can print; so it’s slowing down your throughput and keeping you from moving on to other jobs and making more money.

Also, a conveyor dryer doesn’t require putting as much effort into controlling time and temperature to prevent overcuring and scorching or undercuring that may not be apparent until the customer brings the shirts back.

Size

One of the most obvious considerations in dryer selection is size. When determining what size dryer to buy, you need to look at how many pieces you want to be able to cure per hour, not only today, but also in a year or two. Most small dryers can handle about six-dozen shirts an hour. That may sound like a lot when a shop is just getting started, but after a few years’ growth, it may not be enough to keep pace with production needs.

If it’s in your budget, it is better to over-buy somewhat at the outset. Many shops start with an 8-foot dryer, which more than doubles the per-hour throughput capability of the 6-foot unit.

When considering dryer size and production capacity, look at oven length and belt width. Typically, the longer the oven, the faster you can run the belt and still have the same curing time. For example, the five standard dryer lengths we offer have production capacities of:

  • six dozen/hour for the 6-foot
  • 200-300/hour for the 8-foot
  • 400-500/hour for the 11-foot
  • 600-800/hour for the 13-foot
  • 1,000-plus for the 17-foot.

Belt width affects the ease of loading and the number of garments you can fit on the belt. Generally speaking, the wider the belt, the better.

Power

Another even more important consideration is wattage. The wattage is the amount of heat a dryer generates. It also determines the "recovery time" or time it takes for a conveyor dryer to get back up to the set temperature after the garments in the previous load have absorbed the heat. An under-powered dryer can cure prints but not at a fast speed.

Don’t make the mistake of judging a dryer solely by its size. About 6,000 watts is the minimum to look for, with closer to 8,000 watts being preferable, in an 8-foot dryer. As a rule, the bigger the dryer, the higher the wattage should be.

The combination of a longer oven chamber, wider belt, and greater watt density make it possible to cure more garments.

Controls

The ability to control dryer functions and variables also impacts production. Belt speed and temperature controls are key. They make it possible to adjust for various types of garments. This is important because in order to get a cure, you not only have to get the ink up to temperature, but you also have to raise the temperature of the garment, and fabrics differ in the time they take to reach a given temperature.

Today, digital controls are pretty much the norm. Digital generally is more precise than analog, plus it provides a digital readout -- it not only controls the temperature, but it tells you what the temperature is.

Air, Infrared and Convection

The type of dryer and the role that air does or does not play in the drying process is another selection consideration. There are two basic approaches to curing in electric conveyor dryers: infrared and convection.

Basically, an infrared dryer heats up objects and not the air. Convection heat is moving air.

Infrared heat is very quick, but it also is unforgiving. Belt speeds have to be controlled closely, as does the distance between the substrate and the heating elements.

Convection heat isn’t quite as fast, but it is more forgiving because the entire garment, along with the surrounding area, receive about the same amount of heat.

Dryers that use both infrared and convection or "air" offer the best of both approaches, combining the speed of infrared with the forgiveness of convection. The circulating air also can help forestall problems with cold spots or uneven heating. There are dryers that offer infrared and convection, and some take the concept a step further by incorporating a "flash phase" feature that bypasses the temperature control in the first group of elements. Garments are hit with a lot of infrared heat at the start, then go into the controlled convection heat zone.

There also are two types of heating elements in dryers. One is the ceramic-panel type that is common in spot dryers. The other is a quartz element.

There are two types of quartz elements, as well. There are "highway quartz" elements of the type that are used on expensive flash-cure units on automatic presses, which have a very high replacement cost, and there are quartz elements that consist of wire encased in a quartz tube. The latter do a good job and are significantly less expensive to replace.

Space Requirements

The amount of space a dryer requires also must be taken into account. In addition to the actual "footprint" of the unit, there has to be enough room to get around at least three sides of the dryer. Room also must be allowed for loading and unloading.

When figuring space needs, it’s important to consider the dryer in the context of the surrounding shop. Will you be using the dryer to cure garments from multiple presses at the same time? If so, there must be sufficient space to keep people out of each other’s way. Will the type of work you’re doing require lengthening the in-feed or exit-feed for easier loading, additional cooling time, etc.? Adding a section increases space needs.

Voltage

You also need to make sure a dryer’s voltage requirements are compatible with your facility. Most dryers run on 220 volts, although there are exceptions. It’s important to know whether 208, 220, or another voltage is available in your building. You also need to know whether your shop is wired for single-phase or three-phase and how many amps are available on the circuit. Finding out these things beforehand ensures not only that your dryer will work, but that it will work as efficiently as possible. It also can help you keep operating costs to a minimum by enabling you to buy the dryer that will accomplish your goals while drawing the least amount of energy.

Maintenance

Keeping your dryer free of lint is key. So how easily you can access the oven chamber is also worth considering. Some dryers must be disassembled to get inside. Others feature an access panel that can save time and encourages regular maintenance.

Belt Tracking

How smoothly your belt runs impacts its functioning and its longevity. If a belt runs crooked, it can run into the side and be damaged. A four-point belttracking system adjusts the belt alignment on all four corners of the dryer, which makes it a lot easier to get the belt running true.

Installation

Besides ensuring a dryer is a good fit for your operation, make sure it’s a good fit for your shop. Find out the unassembled dimensions of the dryer and compare them to your doorway. Also, since dryers often are heavy, make sure that you’re equipped to receive the dryer. If you don’t have a dock or a forklift, you may need to pay for a lift service. Check first to avoid time-consuming surprises and unanticipated expenses.

Assembly itself is usually pretty simple and something you can do yourself. But it is important to have a licensed electrician actually connect your dryer.

Also, find out ahead of time what state and/or local regulations say about venting and exhausting. Regardless, you want your work environment to be as pleasant as possible, with minimal fumes from sizing, for example. Therefore, an exhaust system can be an important feature.