Calculation of air receiver volume for a compressor

From compressed air | 05/04/2017

To increase the efficiency of work using compressed air, the vast majority of compressor units use receivers - tanks for storing air under the required pressure. Depending on the intensity of work, receivers of 50, 100 liters or even more can be used.

Why do you need a receiver in a compressor?

The compressor receiver performs several important functions:

1. Stabilizes the air pressure supplied to the working area (differences in pressure values ​​are inevitable, since a single cycle of operation of any compressor involves a suction phase and an air injection phase).
2. They provide the supply of compressed air for some time in the event of interruptions in the operation of the compressor, or when an additional consumer is connected to it.
3. Cleaning the air from accumulating condensate, since high air humidity, which increases with increasing air pressure, leads to intense corrosion of the steel parts of the compressor.
4. The accumulation of compressed air in the receiver for the compressor leads to a subsequent reduction in the total vibrations in the system, which, in turn, reduces the overall noise level and reduces the level of loads on the base of stationary units.

When performing work involving the production of compressed air in particularly large quantities, a standard receiver may not be enough. For example, when sandblasting surfaces with a large area, in order not to purchase a more powerful compressor, an additional receiver is often used.

The presence of a receiver, in addition, allows you to use the compressor periodically, i.e., reduce its consumption of electrical energy.

Structurally, the compressor receiver is a sealed tank with a certain capacity. For mobile compressors, receivers up to 50...100 l are used, for stationary ones - up to 500...1000 l. It is equipped with air-cleaning filters, condensate drains and shut-off valves for connection to the main unit and to the working device that consumes compressed air - nozzle, spray gun, etc.

The container is made of steel, from corrosion-resistant steels of type 10ХСНД or 16ГА2Ф. In exceptional cases, for particularly low-power compressors, receivers can be made of plastic or even high-strength rubber.

The layout of receivers can be horizontal or vertical. The first is used in mobile units, the second – in stationary ones. Each variety has its own advantages and disadvantages. In particular, it is easier to drain condensate in vertical receivers, but horizontal receivers are more compact and require shorter pipelines.

Errors in calculations

It should be noted that using an air collector with insufficient volume will lead to frequent changes in the operating mode of the station and its faster failure.

An air collector that is too large will subject the compressor station to unnecessary operating loads, which will cause the working chamber to heat up more and individual elements to wear out faster.

Incorrect calculation of the receiver volume for a screw compressor can negatively affect the durability of the pneumatic system, increase workloads and cause an emergency shutdown of the station due to frequent mode changes.

How to choose the optimal receiver parameters?

In addition to capacity, the compressor receiver is also characterized by:

1. Limit values ​​of air humidity.
2. Operating conditions (allowed difference in external ambient temperatures -15...+40ºС and relative humidity no more than 75...80%).
3. Requirements for the installation location (away from heat sources, flammable and explosive materials, as well as in an atmosphere contaminated with mechanical particles - for example, near circular saws).

The requirements of PB 03-576-03 (rules for the design and safe operation of pressure vessels) also prohibit the operation of receivers that have not passed the performance check of the tank walls, as well as those that have external surface defects - cracks, dents, traces of atmospheric corrosion.

The selection of receiver characteristics for a compressor is done as follows. Set the required compressed air consumption, duration of its consumption, minimum and maximum pressure values. Next, using standard online calculation tables (for example, //www.kaeser.ru/Online_Services/Toolbox/Air_receiver_sizes/default.asp) determine the required parameter. For example, with initial air flow data of 0.1 m3/min, peak load duration during operation of 5 minutes, permissible pressure difference minimum/maximum of 3/4 atm, the optimal volume of the receiver tank will be 500 liters.

This method is focused on the time it takes to completely empty the receiver. There is also a simplified tabular method that correlates the volume of the receiver with the power consumption of the compressor. The ratios used in practice are:

• For a compressor with a power of up to 5 kW – up to 100 l;
• For a compressor with a power of up to 10 kW – up to 300 l;
• For a compressor with a power of up to 20 kW – up to 550 hp.

It is recommended to obtain intermediate values ​​by interpolation. There are also experimental dependencies. For example, the capacity of the receiver tank cannot be less than the performance of the compressor for 8 seconds of its continuous operation. In particular, with a compressor air flow rate of 400 l/min, the tank volume will be no less than:

V = (400×8)/60 = 53.33 (l)

The procedure for making a homemade receiver

The sequence of manufacturing an additional vessel looks approximately as follows.

1. Cleaning an old vessel from gas residues. To do this, you will need to clean it of gas residues. The inlet valve is removed, while using an electric tool, for example, an angle grinder, gas residues may remain in the housing.
2. The vessel is filled with water and allowed to stand for 24 hours. Then it is drained and the internal cavity is cleaned of dirt.
3. After this, splitters under the sleeves are welded into the cylinder, but it is also permissible to install threaded fittings; to increase the tightness when installing plugs, it is necessary to install sealing gaskets.
4. A homemade receiver must be painted with weather-resistant paint.
5. A condensate drain is installed in the assembled and painted maneuver - its place is at the lowest point of the tank, and a pressure gauge is installed in the upper part. The brand of condensate drain must be consistent with the compressor capacity and thread sizes. The cost of such a device ranges from 2500 to 3000 rubles.

When operating a condensate trap, we must not forget that its installation on an auxiliary gas storage tank is mandatory. Before switching on the operating load, it is necessary to check the condition of the electric drive to ensure that it can be operated with an auxiliary gas container.

To do this check, you need to turn on the compressor and use a flow meter to check the pressure surge during long-term operation (about 20 minutes).

If the minimum pressure corresponds to the declared characteristics of the supercharger, then operation of the assembled structure is quite acceptable. If the pressure drop is below the permissible level, then the use of this equipment is in question and it is undesirable to use it.

Which brand of air compressor is better to choose?

Compressor units can be screw, piston, oil, or oil-free. Some are good for the garage, others for professional auto repair shops, and others are environmentally friendly. Having decided on the type of device, it is important to choose a manufacturer. The best compressor companies are:

• Fubag is a German brand that produces professional and semi-professional equipment for cars, construction, and welding. The products of this company are famous for their excellent quality. Fubag factories are located in Germany, Switzerland, France, Italy.
• Metabo is a manufacturer with almost a hundred years of history from Germany. Metabo produces electric tools, batteries, and compressors. All development and production are carried out in Nürtingen.
• Caliber is a Russian company founded in 2001. Since then it has been actively developing. The caliber is produced by power tools, garden tools, pumping and battery units.
• Kraton is a manufacturer that began its activities in 1999 with the production of saw blades and cutting wheels for metal. Now it offers modern power tools, automotive products, household air compressors, drilling equipment, and hand tools.
• Denzel is a German brand known for its advanced approach to the production of equipment for construction, repair, automobiles, and garden tools. The entire range has international certificates of conformity.
• F iac is an Italian leader in the production of compressor equipment. Romano Lucchi founded the company in 1977. Now Fiac products are represented in dozens of countries around the world.
• Aurora is a diversified company that produces welding equipment, generators, compressor units, and high-pressure car washers. Aurora products are in greatest demand in European countries and Russia.
• Remeza is a manufacturer of compressor equipment and nitrogen generators. The devices are intended for household and industrial use.
• Wester , a company that began producing burner devices in 1995, has significantly expanded its product range. In 2009, Wester put into operation a full-cycle automated plant; work on it is carried out around the clock.
• Fini is an Italian company founded in 1952. At that time, Fini produced electric motors. Now the brand is engaged in the development and production of compressor units.
• A bac is a concern founded in Italy in 1948. Abac produces air compressors. Factories are located in Italy, other European countries, the United States of America, and Southeast Asia.
• Comprag is a German company that has currently opened a plant in the Moscow region. Comprag produces compressor equipment of various designs.

Best Air Compressors

An air compressor is needed to inflate tires as planned, or to inflate them in case of some trouble on the road. In addition to car wheels, the device will quickly inflate a boat, mattress, etc. Such units are used during construction and finishing work, but only the best air compressors can become a reliable assistant and last a long time.

Is it beneficial to place the receiver outdoors?

• depends on the climate zone,
• the receiver is more effective as a second heat exchanger if it is located in the open air,
• can reduce high temperatures in the compressor room.

Placing the receiver outside allows you to save space in the compressor room. However, this is only justified if the outside air temperature never drops below 0°C. At subzero temperatures, the receiver may freeze up and rupture if it lacks thermal insulation and the thermal energy created inside the receiver is not enough to maintain a positive temperature of the receiver. In such cases, it is necessary to provide heating and constant monitoring.

If climatic conditions are in your favor, you can place the receiver outside. This is beneficial since the air outside will likely be colder than the air in the compressor room. This will help improve the efficiency of the dehumidifier by lowering the air temperature as it approaches the dehumidifier.

Another advantage of placing the receiver outside is the reduction in temperature in the compressor room due to the fact that the heat generated during receiver operation is generated outdoors.

The best compressor manufacturers - which company to choose

A compressor is a structurally complex, expensive unit that is purchased only after preliminary information preparation. There are many parameters that are taken into account when choosing: one of them is the name of the manufacturer.

That is why we list the following 5 companies that have earned the trust of customers:

We recommend that you immediately decide and choose a specific model. To do this, you just need to read this article.

Calculation of the receiver as a capacity to compensate for consumption peaks

In the chapter “Creating a reserve of compressed air to compensate for consumption peaks” above, we talked about another function of the air receiver - compensation for peak consumption, when compressed air consumption briefly exceeds the compressor’s performance. The task of the air receiver in this case is to prevent the pressure in the compressed air network (including in the receiver itself, of course) from falling below a certain minimum permissible value during the entire peak of consumption. The formula for selecting a receiver for this purpose is given below:

Formula for calculating an air receiver to compensate for consumption peaks

, where VR is the required volume of the receiver [m³] tR is the duration of the peak consumption [min] LB is the peak consumption of compressed air [m³/min] Q is the compressor capacity [m³/min] pmax is the pressure in the receiver at the beginning of the peak [bar] pmin - minimum permissible pressure in the receiver at the end of the peak [bar]

Classification

In addition to the fact that there are mobile and stationary receivers, experts note other design features of air collectors that allow them to be considered different types of products. So, there are horizontally and vertically oriented containers.

At the same time, horizontal receivers are more compact and make it possible to economically accommodate a pump, electric motor and other auxiliary equipment. A characteristic feature of this arrangement is the minimum length of connecting pipelines. Thanks to these features, horizontal receivers are widely used both in household compressors and in automotive pneumatic systems.

Types of receivers and their connection diagrams

Receivers can be horizontal or vertical.

A horizontal air collector is usually part of a piston or screw compressor.

Horizontal air collectors are installed for a compact location of the compressor unit and electric motor.

For the needs of large enterprises, receivers can reach a volume of up to 80 m3; the advantages of horizontal receivers are their stability and ease of maintenance.

Vertical air collectors can significantly save space in the production cycle, which ultimately affects the cost of the product.

An enterprise usually installs several dozen vertical receivers, connecting them in series or in parallel.

The option of parallel arrangement of air collectors has a significant advantage: the throughput of the system becomes equal to the sum of the throughputs of all receivers in the network. In addition, in case of repairs, you can turn off one of the system’s receivers.

With a sequential arrangement of air collectors in the network, the throughput is lower, but each receiver also serves as a kind of mini-separator, purifying the air from excess moisture and oil.

Passing through series-connected air collectors, the air is repeatedly purified from the emulsion of moisture and oil, reducing the load on the units and extending their service life.

The maximum throughput of a system with daisy-chain connection of receivers is equal to the min throughput of any receiver of the entire system.

At enterprises there is now a tendency to avoid purchasing receivers with large volumes, installing a certain number of small air collectors (up to 1 m3). The installation of such receivers is not controlled by Rostechnadzor.

Equipment The receivers we offer are equipped with: a safety valve; a tap (designed to drain condensate); fittings for connecting the main pipeline and instruments; a device for measuring pressure (pressure gauge); passport of the established form. At the Customer's request, the configuration can be changed. The material from which the air collectors are made is low-alloy and carbon steel. Climatic design of air collectors “U1–U4” in accordance with GOST 15150-69. Their estimated service life is 20 years.

Which type to choose

When you start choosing a compressor, you first need to understand what kind of work you will be doing. If you are deciding how to choose a compressor for painting, then consider all the data from the table above. There is no need to start searching with the wording “I want the best”, “to have a smaller one” or “which company is better”.

So, for some, the issue of mobility and size will be fundamental. In such cases, piston coaxial compressors are the best. They have the smallest dimensions. In terms of mobility, the best ones are oil-free compressors that do not have a receiver.

However, the main task of the equipment is to provide compressed air to the tool. The choice should begin with studying the needs of your instrument. Our table will help you here.

Data on the air consumption of the tool during operation can be found in the manufacturer’s data sheet. During the selection process, you need to pay attention to ensure that the output pressure from the line is not less than that required by the pneumatic tool. Let's give an example. To operate a pneumatic drill, pressures of 6-8 bar are required. For normal operation, you will need equipment that will have a working pressure of 8-10 Bar. Remember that there will be losses that arise due to pressure differences in the system. If you purchase a unit with exactly the same pressure as a drill, then during changes the compressor may simply not start the drill.

Air Compressor Rating

Air compressors have a wide range of applications, as well as a wide variety of models that differ in design. Analyzing devices according to all parameters is not an easy task, but by highlighting a number of main characteristics, a rating of units was compiled. So, the comparison took into account:

• Power;
• Performance;
• Maximum pressure;
• Compressor type;
• Pressure gauge type;
• Receiver;
• Durability;
• Price.

During the study, screw units, oil piston units, and oil-free piston units were examined. In each category, leaders are identified based on a set of indicators.

How to choose a compressor for painting and inflating car tires

If there is a need for pneumatic tools, then there is a need for a compressor - a machine that compresses air and pumps it into an impact wrench, tire inflator or spray gun. These units are technically complex, in addition, more than a dozen companies are involved in their production, naturally, there are many offers on the market. It is not surprising that in the process of acquiring such equipment necessary for work, it is necessary to consider a large number of parameters. The article tells you how to successfully cope with the task of making the right choice and not make an annoying mistake when purchasing, in detail.

Features of choosing a compressor for home or work

Construction technologies and equipment do not stay in one place. Every year, old instruments are improved and new ones appear. Similar updates have not spared air tools, because... every manufacturer always wants to sell the best product to its end consumer. Therefore, when you decide to figure out how to choose a compressor and outline your goals, you should pay attention to its technical parameters. It is knowledge of the best characteristics that will allow you to choose the best model for subsequent successful work.