FROM AIRLESS TO LVLP SPRAY GUNS: MANUAL FINISHING TECHNOLOGIES ARE EVOLVING (PART TWO)

By Steve Milhoan

Today, there are many different ways to manually apply coatings in the finishing world. This article will list some of the techniques and give a brief description along with the pros and cons of each technique.

In my previous article, “From Paint Brushes to Spray Guns: Manual Finishing Technologies are Evolving,” I covered three techniques of manually applying paint: paint brushes, conventional spray guns and high volume low pressure (HVLP) spray guns. In this article, I will continue to explore the evolution of manually applied paint by covering the following technologies: airless, air-assisted airless and low volume low pressure (LVLP) spray guns.

AIRLESS SPRAY GUNS

Airless spray guns have a working pressure in the range of 700 to 5,000 psi. Airless guns must be used with a pump that creates adequate pressure to atomize paint through a small orifice nozzle (usually in a range of 0.09-0.35). Most coatings can be sprayed with very little thinner added, thereby reducing drying time and decreasing the release of solvent into the environment.

Pros: Coatings penetrate better into pits and crevices, uniform thick coating produced, high speed of coatings applied
Cons: Cannot produce class A finish quality, risk of injury due to use of higher pressure

AIR-ASSISTED AIRLESS (AAA) SPRAY GUNS

Air-Assisted Airless (AAA) uses the same spray tips as an airless spray gun and also requires a pump to deliver material to the applicator’s tip. The difference between the two technologies is the pressure range and the added air to help with pattern distribution and atomization. AAA is usually used in a range of 300 to 600 psi. At this low pressure, the pattern that is produced by the AAA tip is heavy in the middle with tails on the outside. By introducing a low amount of air (10-20 psi), it blends the pattern together and also adds some additional atomization to the spray process. This low pressure and added air increases the transfer efficiency and final finish quality.

Pros: High transfer efficiency, super fast application speed—one of the fastest available, EPA and government approved
Cons: Requires a pump and a small compressor for operation, more startup costs than HVLP systems

LOW VOLUME LOW PRESSURE (LVLP) SPRAY GUNS

LVLP spray guns are air atomized spray guns, which offer greater pressures than HVLP, a faster working speed and slightly higher atomization levels. Due to industry demands for higher production speed, most reduced pressure guns are approved for use in about 90% of the U.S. They are approved even in California’s San Francisco bay area, which verifies that the low over spray levels, while slightly higher than HVLP, are still very excellent.

Pros: Faster application speed than HVLP, among the highest finish quality, great material savings—similar to HVLP
Cons: Requires a pump and a small compressor for operation, more startup costs than HVLP systems

Which manual finishing technology will help you achieve all your goals? OTP Industrial Solutions has finishing and fluid handling experts on-call to help answer any question and solve any problem. We can introduce you to the best finishing technology for your specific needs, using our technical knowledge and broad product support to get the right tools and technologies in your hands today.

THE IMPORTANCE OF USING A VARIABLE FREQUENCY DRIVE (VFD)

By Alan Wharton

Technology improvements have made Variable Frequency Drives (VFDs) a more reliable and cost effective method of speed control. With the advancements of VFDs in recent years, they have evolved into highly sophisticated digital microprocessor controllers and high frequency power devices.

Now that VFDs have become so accepted in the industrial market, the potential for retrofits and new project installations remain very high. Demand for energy savings and process control will continue to provide double-digit growth for many years to come—and the two most common applications for maximum energy savings remains in centrifugal pumps and fans. With the recent requirements to reduce the overall demand on the power grid, there are many utility companies providing rebates and cost-sharing programs that, in some cases, will provide product at virtually no cost to the user.

History has shown that although you can achieve two to six percent energy savings with premium efficient motors over standard efficient (EPACT) motors, VFDs can provide up to 35 percent savings if applied properly. In many cases pumps and fans are sized according to worst-case-scenario using maximum flow conditions or by using a “rule of thumb” approach to apply a 20 percent oversizing formula. It is important to evaluate the complete application and system characteristics to determine the potential savings available.

In addition to energy savings, other benefits include the reduction and/or elimination of motor starters, less stress on the motor windings and bearings, and a decrease in stress and wear on the pump or fan itself. Taking all of this into consideration will equate to a smoother, longer lasting, more controllable and more efficient operation process.

Please contact OTP Industrial Solutions to receive technical assistance on how to apply VFDs to your application or to evaluate your process to determine potential energy and cost savings opportunities.

WHY IS SHAFT ALIGNMENT IMPORTANT AND HOW DOES IT AFFECT SERVICE LIFE OF ROTATING EQUIPMENT?

By Matt Crankshaw

Shaft alignment is an important step in the setup of new or repaired pumps and gearboxes.

Some of the potential problems that may arise from not properly aligning rotating equipment includes:

• Excessive vibration and noise
• High overhung loads on bearings, which can lead to premature failure
• Non-uniform wear on mechanical seals or packing
• Accelerated wear to shaft couplings

Shafts may be misaligned in three separate ways; parallel, angular and axial. Misalignments can occur during shipping, after new installations or from vibrations during equipment run time.

To ensure the highest level of accuracy when performing shaft alignments, OTP technicians use lasers. The lasers are mounted on the shafts of the equipment to be aligned. As the shafts are rotated, the lasers measure the deflection of the shafts and calculate how many shims to add to get the correct alignment. This method of alignment is the most accurate and repeatable.

Protect your pumps and rotating equipment by aligning them properly and you will be rewarded with increased uptime and lower overall maintenance costs. Please contact OTP Industrial Solutions to experience our precise shaft alignment and other rotating equipment repair services.