Is a reciprocating air compressor more dependable and multifaceted than the other types? It might be, and also very adaptable. Yet with each kind, there are advantages and disadvantages. One might be the best and most expensive one available but might not fit your particular needs.
So if you want one for your home which you can use for your DIY projects or household chores, you have to be aware of everything about this reciprocating compressor: what exactly it is, what it does, or why it might be the best one there is.
Table of Contents
What is it?
This well-rounded piece of machinery functions by reciprocation, which is an interchanging movement that goes back and forth.
It is also called a piston air compressor. It is also named this way because it utilizes pistons impelled by a crankshaft to provide air at high pressure. This action is known as positive displacement, which means it increases the compression in the air to pressurize it.
To further illustrate it, this compressor type has cylinders with pistons within them. Each cylinder has a head with a closed end next to it. And is finished by a piston on the other end. The cylinder valves are found underneath the valve pockets. When the first stage of pressurization occurs, air passes into the cylinder through the suction valve, activated by the piston’s movement, which creates a vacuum force.
Then it reciprocates, meaning the entire movement mentioned above is reversed. It, in turn, starts pressurizing the air. After the pressure inside the cylinders surpasses the limit in the discharge pipes, air can now go out that you can use for numerous tasks.
It is essential to understand everything there is to know about this compressor type if you plan to purchase it to aid in your DIY hobbies and crafts.
This kind of knowledge is essential and very useful, like how it is designed or its many counterparts. Knowing them will eventually help you in using it to its full potential and maximum effectiveness.
How does it function?
The power of this compressor type generally comes from a diesel engine. It is done by a system of belt drives that continually functions whenever the engine is switched on.
The whole cyclic flow is alleviated by an unloading mechanism and controlled by a regulator, usually mounted on top of the unit. A regulator’s main function is to apply a specific cut-out pressure and intake. Here are some of its basic functionalities:
Intake cycle
This cyclic process begins when the cylinder draws through the piston downward. This kind of movement creates a vacuum between the cylinder head and the piston top. It brings low compressed air to the cylinder through many inlet valves. The valves are mounted above the piston head as it goes down. In this stage of the process, the discharge valve is shut off, and inlet valves remain on.
Then the piston goes back up, actuating the inlet valves to turn off so the air will be forcefully trapped inside the cylinder. The piston will continually drive up, thus reducing the area in the cylinder occupied by the air, thus resulting in compressed air.
The pressurized air within the cylinder will rapidly exceed the opposing action of the discharge valve. It will then open the valve and admit the new compressed air to go out before the cyclic process restarts.
If the discharge valve is closed, it will halt the air from going back to the cylinder’s low-pressure area after pressurization has been achieved.
The process of unloading
Once the air in the receiving tank has attained the cut-out threshold of the highest pressurization, the pressure control regulator will let the compressor unit unload.
There might be only a portion of total unloading, depending on how the high-pressure reciprocating air compressor was conceived.
As the newly pressurized air is utilized, the tank’s pressure level will slowly decrease. Once it goes down to the preset loading point, the pressure control regulator signals the unit to begin the pressurization cycle again and refill the tank pressure.
Duty cycle
This process is one of the most crucial pieces of basic info about the reciprocating piston air compressor.
The duty cycle is ascertained by taking down the amount of time the unit spends being loaded, then equating it to the total time it operates while being unloaded or shut down. These small reciprocating compressor types are made to have a full load time of twenty to thirty percent. The remaining seventy to eighty percent time should be unloaded.
You have to make sure that your compressor unit is functioning within the limits of the duty cycle to prolong its lifespan. If you select a comparatively small one for your DIY applications but increase the load and dismiss any air leaks, it will force the system beyond its limitations. Thus, resulting in untimely malfunction of many of its moving parts.
Lubrication
The drive engine pump can share some of its lubricating substances with some types of large reciprocating compressors. Yet, not all kinds can do this.
In a reciprocating piston compressor, the lubricant supply from the sump is crucial in keeping the whole system totally oiled and operating correctly.
To achieve maximum potential, you will have to modify the changeover intervals of the lubricant, as mentioned in the user’s manual. It is because it would not allow for any additional needs of the unit.
The new interval schedule has to allow the heat load that the unit imparts to the lubricating substance. This way, you can get an exact gauge of the significantly lowered lifespan of the lubricant.
Cooling
Most engine-powered compressor types use lubricants as the principal cooling agent. There is an engine oil cooler within the unit. It can cool down the lubricant, which cycles through the whole system.
The fan in the engine air cooler produces a cool air current. It can help in extinguishing the heat emitted from the unit, along with any discharge of exhaust.
The cooling components within the unit are essential in making it last long as it could. Without it, there is a greater risk of surpassing the temperature limit if it exceeds the duty cycle recommended by the manufacturer.
The lubricating agent can prematurely degrade if it will get too hot and surpasses what was recommended by the manufacturer. It would mean you have to alter the lubricant more often than before. This process helps in making its system tougher, run smoother, and last longer.
Uses of a reciprocating air compressor
This handy piece of machinery can be very useful at home, which can aid in your DIY hobbies and chores in general. If you are looking to open a small enterprise, it is also practicable and can assist you in your endeavors.
Here is a few of its uses in many small to medium businesses:
- Spray painting vehicles
- Sandblasting cars in machine shops
- Sanding the car body
- Sanding wood
- Air blow gun for cleaning engines
- Making snow for winter sports, entertainment, and displays
- Air powered tools for garage use like nail guns, drills, etc.
- Small scale medical and dental equipment
If you have a modest agricultural business and want to advance it to the next level, you can make many upgrades, along with this reciprocating type:
- Spraying pesticides or fertilizers to crops
- Moving feeds in a conveyor belt from place to place
- Provide ventilation to greenhouses, barns, etc.
- Giving power to different dairy instruments for cow milking, transporting farm equipment, etc.
This compressor type is also applicable for big business and vital for their continuous operability. Here are some of its uses:
- Pneumatic tools for cutting and welding
- Automated machine system
- Monitoring equipment
- Ejecting parts from molds
- Air-powered tools for packaging and finishing
- Pneumatic chucks, knives, clamps, and positioners
- Molding tanks and plastic bottles
- Machinery adjustments for roller and feed
Compressors in general, are indispensable for every use, and most people do not realize this. Even freezers and refrigerators have a compressor unit within their system, which is utilized to chill the air and make it icy.
Even HVAC systems use them as a cooling mechanism. It can also be used in pastimes and activities like scuba diving and paintball.
Types of reciprocating air compressor
Single acting
This compressor type has only one side of the piston is utilized for air pressurization. Although, the other side is linked to the crankshaft and is not used for pressurization.
The way it operates is pretty straightforward. In a single-acting unit, there is an inlet and discharge valve. Both are spring-loaded and whose air current only goes one way.
The inlet valve draws air in as the piston proceeds downward. The discharge valve only opens up after sufficient force has been employed.
This compressor type goes through a single cycle of pressurization for each turn of the crankshaft. It is because the aforementioned valves can only be found at the uppermost portion of the cylinder.
Double acting
In this compressor type, both piston sides are utilized for the pressurization of air. When the air is drawn from one side, the other side then pressurizes it. Both pressurization and suction happen on each piston stroke.
The way it works is q little complex. There are inlet and discharge valves on both ends of the cylinder, which results in two pressurization cycles as the crankshaft finishes one turn.
The design makeup of the double-stage reciprocating unit makes it very effective. It is why many large industries use it as a means of energy for their massive equipment.
These types also emit strong vibrations, which necessitates vibration isolation and ensuring the entire system is fixed on a solid foundation.
Single-stage
A single-stage reciprocating compressor is ideal for small-scale tasks at home and your DIY projects in your workshop. It will be with you for many years if you only use it infrequently and only yourself alone.
But if you have many tools that require power from pressurized air, then the dual-stage one would be the right one you need.
There are many things to think about before purchasing a single-stage unit. Aspects like capacity, pressure, tank size and horsepower are crucial. These are essential features for any other compressor type, which you as a buyer ought to know beforehand.
These compressor types are reasonably common for many reasons. It is usually because of the usefulness around the house and their compact stature. Compared to the other types, like the rotary screw units, they are reasonably low-priced.
Dual stage
A dual-stage reciprocating compressor is usually chosen over a single-stage one of its usage is for large-scale applications that require lots of power. The most common ones of this kind are the rotary type and piston type. Both are known as positive displacement units.
There are also two cylinders: a high-pressure and a low-pressure one. The second is smaller than the first one to be able to alleviate further pressurization. Between the storage tank and the inlet filter, these two different-sized cylinders permit the trapped air to undergo two stages of pressurization.
In the first stage, the air is sucked into the cylinder that can only accept low pressure. It passes through an inlet filter into an air suction system. At this point, a piston compresses the air, with a rate of forty to seventy PSI.
This cylinder used here is larger and can take in a larger air volume. However, the pressure is only low.
The air at this point will heat up. Before reaching the second pressurization stage, the hot air will cool down to a lower temperature. This procedure enables its functionality to be more effective and to lessen the strain.
In the second stage, the newly cooled and pressurized air will go to the cylinder that can only accept high pressure. It is also a smaller cylinder that can only take in lower air volume. At this point, the pressure can reach as high as one hundred seventy-five to two hundred PSI.
After this procedure, the highly compressed air cools down and goes to the tank for storage, which functions as a reservoir of stored energy. It is used for stronger applications in larger industries like beverage and bottling manufacturing. Car maintenance and assembly, etc.
Single stage vs. dual stage
In many aspects, both single and double stage are very similar. The main difference is that the latter’s pressurized air does not directly go to the reservoir after the first compression. Instead, it will go to the second pressurization stage (as mentioned in the previous section).
The two-stage unit, in turn, produces a lot more power, which is why it is utilized in large industries wherein continual usage is crucial.
However, more power is equivalent to more energy usage, which, in turn, incurs more costing and maintenance. So you usually would not find these types in enterprises that only require less power.
The single-stage ones are found in small-scale endeavors and used in airpower tools in garages, workshops, etc., which only needs more than one hundred PSI.
Diaphragm compressor
Its other name is a membrane compressor and is still regarded as a reciprocating compressor. It uses a revolving membrane to draw air into the system.
It operates with two systems: air pressure and a hydraulic system. There is a protective wall made of an elastic metal diaphragm that separates the two.
The compressor box and the rotating membrane are the only parts that interact with gas. Therefore making these types the only ones that can come in contact with explosive and toxic gases, instead of only air.
Recip compressor vs. other compressor types
If you compare a compressor unit reciprocating, to other compressors that utilize centrifugal and rotary screw movements, are any advantages and disadvantages?
Maintenance and parts
You need to carefully watch over the pistons in a reciprocating unit due to their sensitivity and wear and tear. However, there are other parts you need to keep a close eye like connecting rods, valves, crankshafts, etc. These must function in harmony to lessen any wearing and tearing.
Yet, there are still other components that need observation, thus be challenging for you. The good thing here is that these parts are not as expensive and complicated as the centrifugal and rotary screw ones. Thus, it will cost less in maintenance.
Heat output
Once the compressor is switched on, heat will be emitted and will have a palpable impact on its strength and longevity.
A rotary screw unit has screws that revolve around each other without coming into contact with each other. Thus, emitting less friction.
Yet, with reciprocating types, there is friction happening in the piston’s movement and other parts within. Due to this reason, it requires more maintenance.
Pressure
When you compare a reciprocating unit to a rotary screw one, the former is far better in how much pressure is brought forth. And oftentimes, makes twice as much.
Concerning centrifugal units, they can emit 1.25 times more discharge pressure than a reciprocating one.
Noise level
The sound coming out of a functioning compressor is not always considered a problem. Yet if you need some semblance of quietude while working on your DIY projects, it would be better if you would not have a double-acting compressor close by, which can be loud and distracting.
A rotary screw type emits the lowest noise, and the centrifugal one is the noisiest.
If you want a unit that has a balance of the least sound emission and the most powerful and effective, the single-acting one is the best choice.
Pricing
How much a compressor unit will cost is always the bottom line when selecting the right one that fits your needs. A typical reciprocating device provides more power with a lesser upfront price compared to centrifugal and rotary ones.
Yet, the lifespan of a reciprocating unit is shorter than either of the two. Centrifugal and rotary units have fewer components that move and have friction. So they would incur a lesser cost for replacement parts and maintenance.
But if it undergoes regular preventive maintenance (which is a process of administering system checks), the costing will be less severe.
Efficiency
Reciprocating compressor types are well regarded in the business as the most energy-saving kind among all the others for lots of applications. For that simple reason, they need more maintenance.
Reciprocating vs. rotary screw, based on performance
The two compressor types are similar in many respects, like their compactness and mobility. But performance-wise, they have many differences that can be advantageous to some, but not to others.
Granted, more people are familiar with the reciprocating type because they do not know the difference between the two and only know how they are used.
Here are some key advantages of the rotary screw types over its reciprocating counterpart:
- It works faster- In general, the rotary screw type supply more air compared to the reciprocating type. And can deliver more air without the need for the storage tank.
- It works longer- It can function at one hundred percent duty cycle. Most reciprocating types can only run at a fifty percent duty cycle, which means it only functions one-half of the time and makes the task longer to finish.
- Worry-free work- Rotary screw types tend to last longer than the reciprocating ones. It is particularly designed to prevent parts to wear out by having the compressor oil create a shield for the internal rotors. And can maintain its performance throughout its lifespan./li>
- More functioning in a smaller package- Rotary screw types weigh lesser and has more capacity in their smaller stature, and can provide enough power for pneumatic tools.
Here are the disadvantages of the rotary screw type:
- More costly
- It needs a skilled technician for maintenance and rebuilding
Conclusion
After learning everything about reciprocating air compressors, you are now confident in choosing the right kind for you. Will you choose it over centrifugal or rotary screw types?
It will depend on your specific needs. If you only need one to aid in your DIY projects in your workshop, then it would be ideal for you. Be surefooted and get one now!
