Many manufacturing companies are pushing their production equipment, including compressed air systems, for every ounce of capacity while, at the same time, cutting their overhead costs. This has put a strong emphasis on the importance of quality maintenance services used to care for these systems. However, proper maintenance requires experienced personnel who are well versed in its operation.

Fiscal realities have forced many companies to downsize their work force. Often the reduced staff must assume additional responsibilities and roles within the operations. Demands on the new work force have increased exponentially and people want to and must work smarter.

To help meet these increasing demands, many companies have reorganized the contribution of maintenance training programs. One of the more obvious benefits of maintenance training is the reduction of unexpected downtime resulting from equipment failure. Employees who know and practice correct operating, assembly and maintenance procedures ultimately help ensure equipment and system reliability.

Training also provides substantial financial benefits. The return on every dollar spent for training is significant. Reduction in costly downtime achieved from training, more than offsets its cost. By operating equipment efficiently, energy costs are reduced. In addition, efficient operation can provide additional benefits such as qualifying for rebates from electric utility companies.

One of the most productive and least costly ways for companies to train employees is with maintenance training programs conducted by original equipment manufacturers (OEMs).

OEMs: The Training Resource

OEMs are in the best position to pass on equipment or system knowledge. Product expertise and historical databases from trouble shooting, trending and failure analysis provide excellent resources from which OEMs develop their training programs.
Many suppliers offer their customers training sessions based on proprietary internal programs. For instance, at Ingersoll-Rand, we maintain certification training programs for our Distributors and Air Center service personnel. These groups need to be prepared to resolve any operational problem for our air compressors. Their training is based upon hands on work with specific units and based on actual experience. With this expertise we assist customers in training their on-site personnel.
Another factor to consider is that equipment manufacturers maintain detailed records on its equipment. OEMs and their field representatives are the only source capable of developing a training course for a specific machine without incurring additional cost. Outside consultants accrue costs to ensure that training materials for a specific year, make and model are accurate. These costs are usually passed on with the cost of the program.

Methods of Training

Maintenance training programs can be structured in a variety of forms, including classroom lecture, show-and-tell or hands-on training. The type or combination of training depends on the student base.

Most people prefer to learn from example and practice rather than lecture. Show-and-tell and hands-on training methods are effective and well received, but can be difficult to provide, especially in large classes. In addition, when large, complex equipment is involved, training can be tedious and time consuming.

Therefore, these methods should be reserved for very small groups of five to seven individuals and when possible, scheduled to coincide with a programmed overhaul of the equipment at the work site.

The best type of training for large groups in a reasonable amount of time is the classroom lecture method. This type of training can be provided at the suppliers' factory, or at the customers' facility.

The training sessions can include lectures supported by interesting, professionally-prepared multimedia presentations. When appropriate, some show-and-tell with component parts should be included for reinforcement. It is also important that a comprehensive reference book be provided to each participant for future reference.

Regardless of the method, each training program should involve a systematic product description. Students should be thoroughly instructed on every component of the machine: what it does; how it goes together; its principles of operation; and what modes of failure can occur. Called a composite approach, this method identifies systems within the machine and builds on it until it forms the entire unit.

Maintenance personnel must be trained to find and correct the root cause of a problem in order to be most effective. A composite approach to training is therefore important because it illustrates the dynamic relationship between various systems within the machine.

Selecting A Program

If your company is considering adding a maintenance training program, check the qualifications of various training sources and see how each fits your needs. Here are some of the issues you should consider:

Identify an Objective Whenever you spend money on training it must be spent with an objective in mind. That objective must be defined clearly and communicated to the trainer well in advance of the school. By setting this goal, both the trainer and participants have a better chance of meeting your objectives.

Evaluate the Instructor's Style and Qualifications The instructor must be able to present material in an interesting, cohesive and accurate manner. In addition, the trainer also must have a working knowledge of the equipment, through personal experience and with customers who operate them.

Academic qualifications are helpful, but the most important qualification is a practical understanding of what each student will need to know in order to identify and solve real world operating problems.

Instructors who have worked in customer service and instructed service certification training programs for large equipment manufacturers have the best and most in-depth experience. They have seen the broadest range of installations and applications of equipment. This prepares them to field wide ranging questions and present examples of problems with which students can relate, and solve in class.

Evaluate Training Materials Course handout material, work books and manuals are very important. Keep in mind that when the course is over, the reference materials distributed in class are the basis of future information for you and your staff. These materials should be easy to read, well organized and applicable to the operating level of the equipment.

When the course is being quoted, ask for a sample of the material for review. If it does not match your equipment or needs, call attention to it well before the class is conducted.

Determine Student Evaluations Consider incorporating a two-part written examination as part of the students' evaluations. The first element is a pre-test -- given either before the class or on the first day -- to assist the instructor adjust the course work for the level of student experience. The final exam determines if the objectives of the course have been met. It should be an open book exam with access to class notes, manuals and references materials permitted.

Determine Course Evaluation Options Upon completion, students should also be able to evaluate the course. This is usually done through an evaluation form. This evaluation allows student respondents to judge how the session benefited their job and the company's operation. Questions should be open-ended to facilitate answers that can be used to improve and fine-tune future programs.

Identify Instructor Feedback Requirements Another very important aspect of maintenance training is feedback from the instructor. If an instructor develops a properly constructed final exam, it will determine if objectives were met and detect strengths and weaknesses within the trainee group. This information exchange permits an experienced instructor with the right background to provide valuable advice. For this reason, an instructor's summary report should be requested as an integral part of the contract for maintenance training.

Schedule Follow -Up Classes A one-day follow-up class six months or a year after the training can be very useful. It serves not only as a review and a reinforcement aid, but it allows the student to share experiences since the last session. In addition, instructors can accomplish more in a shorter period of time after participants implement the concepts and procedures that were previously taught.

Always remember that you have an obligation to help your personnel expand their knowledge, productivity and personal contribution to your department or company. Providing professional training allows maintenance people to expand in the field. The trainees will appreciate the assistance. The equipment will respond with reduced maintenance expense and maximized operation time.

Types of Air Compressors

The three basic types of air compressors generally available include:
· Reciprocating
· Rotary
· Centrifugal

These general types of compressors may be further divided into:
· Single or
· Multi (two, three, or four) Stage
· Packaged or
· Non-Packaged
· Air Cooled or
· Water Cooled
· Lubricated or
· Non-Lubricated

Let's briefly review these three basic types of air compressors.

Reciprocating Air Compressors - Sizes at 100 PSIG --1/2 HP & 1 CFM to 1,250 HP & 6,300 CFM

Reciprocating air compressors are positive displacement compressors. This means they are taking in successive volumes of air which is confined within a closed space and elevating this air to a higher pressure. The reciprocating air compressor accomplishes this by using a piston within a cylinder as the compressing and displacing element.

The reciprocating air compressor is considered single acting when the compressing is accomplished using only one side of the piston. A compressor using both sides of the piston is considered double acting.

The reciprocating air compressor uses a number of automatic spring loaded valves in each cylinder that open only when the proper differential pressure exists across the valve.

Inlet valves open when the pressure in the cylinder is slightly below the intake pressure. Discharge valves open when the pressure in the cylinder is slightly above the discharge pressure.

A compressor is considered to be single stage when the entire compression is accomplished with a single cylinder or a group of cylinders in parallel. Many applications involve conditions beyond the practical capability of a single compression stage. Too great a compression ration (absolute discharge pressure/absolute intake pressure) may cause excessive discharge temperature or other design problems.

For practical purposes most plant air reciprocating air compressors over 100 horsepower are built as multi-stage units in which two or more steps of compression are grouped in series. The air is normally cooled between the stages to reduce the temperature and volume entering the following stage.

Reciprocating air compressors are available either as air-cooled or water-cooled in lubricated and non-lubricated configurations, may be packaged, and provide a wide range of pressure and capacity selections.

Rotary Air Compressors - Sizes 30 CFM to 3000 CFM

Rotary air compressors are positive displacement compressors. The most common rotary air compressor is the single stage helical or spiral lobe oil flooded screw air compressor. These compressors consist of two rotors within a casing where the rotors compress the air internally. There are no valves. These units are basically oil cooled (with air cooled or water cooled oil coolers) where the oil seals the internal clearances.

Since the cooling takes place right inside the compressor, the working parts never experience extreme operating temperatures. The rotary compressor, therefore, is a continuous duty, air cooled or water cooled compressor package.

Because of the simple design and few wearing parts, rotary screw air compressors are easy to maintain, operate and provide great installation flexibility. Rotary air compressors can be installed on any surface that will support the static weight.

The two stage oil flooded rotary screw air compressor uses pairs of rotors in a combined airend assembly. Compression is shared between the first and second stages flowing in series. This increases the overall compression efficiency up to fifteen percent of the total full load kilowatt consumption. The two stage rotary air compressor combines the simplicity and flexibility of a rotary screw compressor with the energy efficiency of a two stage double acting reciprocating air compressor. Two stage rotary screw air compressors are available air cooled and water cooled and fully packages.

The oil free rotary screw air compressor utilizes specially designed airends to compress air without oil in the compression chamber yielding true oil free air. Oil free rotary screw air compressors are available air cooled and water cooled and provide the same flexibility as oil flooded rotaries when oil free air is required.

As you can see, rotary screw air compressors are available air cooled and water cooled, oil flooded and oil free, single stage and two stage. There is a wide range of availability in configuration and in pressure and capacity.

Centrifugal Air Compressors - Sizes 400 CFM to 15,000 CFM

The centrifugal air compressor is a dynamic compressor which depends on transfer of energy from a rotating impeller to the air. The rotor accomplishes this by changing the momentum and pressure of the air. This momentum is converted to useful pressure by slowing the air down in a stationary diffuser.

The centrifugal air compressor is an oil free compressor by design. The oil lubricated running gear is separated from the air by shaft seals and atmospheric vents.

The centrifugal is a continuous duty compressor, with few moving parts, that is particularly suited to high volume applications--especially where oil free air is required.

Centrifugal air compressors are water cooled and may be packaged; typically the package includes the aftercooler and all controls.

Reference :
Website http://air.irco.com

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