Ventilation of industrial premises is a necessity that helps preserve the health of workers and ensure uninterrupted operation of the workshop. To clean the air from various impurities, metal and wood shavings, dust and dirt, powerful ventilation units are most often used " snails " The design of these units includes several fans of different power, and therefore the “snail” can cope with almost any contaminant.
Operating principle
The name of the hood “snail” comes from design features And appearance ventilation. In its shape, it really resembles a twisted snail shell. The operating principle of such a system is extremely simple. It is based on the centrifugal force generated by the turbine wheel. As a result, contaminated air masses enter the suction pipe, which, after passing through the cleaning system, are returned to the room or discharged outside.
Types of snails
Hoods - snails can vary in operating pressure. Each type has its own recommendations for use, namely:
Low pressure fans
- up to 100 kg/m2. These designs can be used in both domestic and industrial premises. They are compact and do not require additional labor during installation.
Medium pressure fans
– up to 300 kg/m2. Industrial use is relevant for such systems. They cope well with various impurities.
Fans high pressure
– up to 1200 kg/m2. Such fans are installed in hazardous industries, laboratories and paint shops.
Depending on the specifics of production, you can purchase fireproof, corrosion-resistant or even explosion-resistant models. The price of such products can be significantly higher, but safety in production should come first.
Also, “snails” can be divided into inlet and outlet. Combining two snails different types into one system, you can easily create supply and exhaust system, which will not only remove polluted air masses, but also supply clean air to the room. Moreover, this exhaust system can also be used as space heating during the cold season.
Operating restrictions
Despite the strength and reliability of industrial snails, there are some restrictions on their use. So, centrifugal fans, commonly called “snails”, are not recommended to be installed if:
- There are suspensions in the air with a sticky consistency of more than 10 mg/cubic meter.
- There are particles of explosive substances in the room.
- The room temperature is outside the range of -40 to +45°C.
Moreover, it is rational to use snail ventilation in large rooms; in everyday life, it is better to install such devices in ventilation shafts, where all the exhaust air from the house enters.
Suitability for home use
Most often, the “snail” for ventilation is used in industrial premises or in home carpentry shops, painting booths etc. It is not advisable to install such ventilation directly in residential premises. After all, a “snail” is an inconspicuous-looking and rather large device that can spoil the overall design of the kitchen. In addition, this type of ventilation is quite noisy and home use may create significant discomfort.
DIY snail
For domestic use, you can make ventilation with your own hands. Of course, such a design will differ from an industrial installation, but it will help significantly save money on the purchase of ventilation. It is worth noting that a high-quality medium-power snail in specialized stores costs around 20 thousand rubles, and therefore for many it remains topical issue, how to make ventilation with your own hands
.
The design of the body of a homemade snail most often includes two parts - an area for placing the engine and an area with blowing blades. Most spare parts will have to be purchased in specialized stores, but these costs will be significantly lower than if you buy ready-made ventilation. So, you will need:
- Frame. You can buy it at a hardware store. It is better to give preference to a metal product.
- Engine. Sold in markets and electrical goods stores.
- Impeller. Can be purchased at electrical appliance spare parts stores.
- Fan. Sold at any home ventilation equipment store.
Creating a ventilation unit with your own hands begins with calculations. In order for the use of snail ventilation to be effective, you need to correctly calculate the power and size of the engine. When installing the device, special attention should be paid to the reliability of the fan and impeller fastenings. With strong air currents, these components can become loose and jump off, which will invariably lead to damage to the ventilation. All parts, including the body, must be made of fire-resistant materials.
Diagram of the ventilation "snail"
It should be noted that self-assembly Such extraction can only be carried out with certain knowledge. If you are not sure that the device you assembled yourself is completely safe, it is better to consult a professional who can assess the correctness of your assembly. If you do not have the skills to assemble electrical structures, it is better to buy a ready-made device.
The mechanism of any fan is based on a rotor with blades attached to it. Their purpose is to move large masses of air for the purpose of air circulation.
The scope of application of centrifugal fans "snail" is very wide. They are used in engineering systems buildings, industrial systems ventilation, drying chambers, household appliances, painting, when blowing machines.
The method of creating air flow by rotating a radial wheel with blades in a spiral chamber gave the name to fans - radial or centrifugal. The blades on the wheel can be straight, curved or wing-type.
Air flow pressure, depending on the number and profile of the blades, as well as their rotation speed, divided into three classes:
- low;
- average;
- high.
Pressure indicators fall within the range from 0.1 to 12 kPa. By swapping the phases of the current at the motor terminals, you can change the direction of rotation of the impeller. This is done with a rocker switch on the engine. This is necessary to change the mode of air intake from the room with the injection of clean air.
Design and operating principle
Fan devices used to move various mixtures of gases and air come in several types. The most popular is centrifugal radial unit "snail".
It has a rotating wheel assembly and blades attached to it. Various models fans contain different numbers of blades.
The operating principle of the snail hood is as follows:
- Air is sucked into the rotor through the inlet;
- The air mass receives rotational motion;
- Next, through the centrifugal force created by the rotating blades, air under pressure is forced to the outlet. It is located in a spiral casing.
Due to the resemblance of the casing to a snail, the fan got its name.
Housing materials
Industrial "snail" may include different materials- depending on the aggressiveness of the application environment. Sheathing of a general-purpose unit operated in non-aggressive gas mixtures with a particle content of less than 0.1 g/cubic meter. m, made from galvanized or carbon steel sheets of different thicknesses. If the environment contains aggressive gas mixtures, characterized by the presence of active gases and evaporation of acids, corrosion-resistant steels are used. This type of snail fan operates at temperatures up to 200 degrees Celsius.
There is an explosion-proof version of the hood housing. It is assembled from ductile metals: copper or aluminum alloys. Here, during operation of the hood, sparking, which is the main cause of explosions, is eliminated.
Impeller
Material requirements for impeller with blades- plasticity and protection from corrosion. Then the wheel will withstand vibration loads and chemical exposure environment. To design the shape and number of blades, aerodynamic loads and rotation speed are taken into account. High rotation speed large quantity slightly curved or straight blades, creates a stable air flow. This creates less noise.
Centrifugal exhaust should be classified as equipment with increased vibration. The cause of vibration is the low level of balance of the rotating wheel. Vibration carries with it the following negative factors: destruction of the foundation at the installation site of the equipment and high noise levels. The installation of shock-absorbing springs minimizes vibration. The springs are mounted under the base of the housing. In addition, some models use rubber cushions instead of springs.
Electric motors
Snail-type ventilation equipment is supplied electric motors with explosion-proof covers and housings. A special paint is used to paint engine casings. protective composition. Most of them are asynchronous mechanisms with a fixed rotation speed. They are connected to a single-phase or three-phase network, depending on the design. In special cases, variable speed motors are used.
Dimensions
The sizes of snail hoods can be different. The diameter of the unit varies from 250 to 1500 mm. “Snails” can represent a single whole or be divided into several parts. In the case of small fans with a solid volute, the rotation angle can be neglected. Simply unscrew the bolts and rotate it to the desired position. Larger models are mostly collapsible. For them, the rotation angle is an important parameter that should be taken into account.
Snail fans get their name from the shape of the body, which resembles the shell of this mollusk. Today this type of equipment is used both in industry and in residential construction in ventilation systems Oh. Manufacturers today offer several models of snails for ventilation. But they all work on the same principle - the centrifugal force created by the rotation of the blades on the rotor captures air through the snail-shaped inlet and pushes it through a straight outlet located at 90° in a different plane to the inlet.
General information about centrifugal (radial) fans
Coil fans have a dual designation (marking): VR and VC, that is, radial and centrifugal. The first indicates that the blades of the working part of the equipment are located radially relative to their rotor. The second is the designation physical principle operation of the device, that is, the process of taking and moving air masses occurs due to centrifugal force.
It is centrifugal fans in ventilation systems that have proven themselves to be positive side due to high efficiency of air removal.
Operating principle
As already mentioned, fans of this modification operate based on the action of centrifugal force.
- The blades attached to the rotor of the device rotate at high speed, creating turbulence inside the housing.
- The inlet pressure drops, which causes the suction of nearby air, which rushes inward.
- Under the action of the blades, it is thrown to the periphery of the space, where high pressure is created.
- Under its action, the air flow rushes to the outlet pipe.
This is how all centrifugal models work, which are installed not only in ventilation systems, but also in smoke removal systems. About the latter, it must be said that their body is made of aluminum alloy or steel coated heat-resistant materials, and are equipped with an explosion-proof electric motor.
Design Features
As already mentioned, the main design feature is the snail. It is also necessary to indicate the shape of the blades. Fans of this brand use three types:
- with straight slope,
- with a backward tilt
- in the form of a wing.
The first position is small fans with high power and performance. That is, they can create conditions in which other models require a large body. At the same time, they operate with low noise levels. The second position is an economical option that consumes 20% less electricity than other positions. Such fans can easily withstand loads.
As for the design that relates to the electric motor, there are also three positions:
- the rotor is fixed directly to the motor shaft through a coupling and bearings;
- through a belt drive using pulleys;
- The impeller is mounted on the electric motor shaft.
And one more feature is the connection points between the fan and the air ducts of the ventilation system. The inlet pipe has rectangular shape holes, exit round.
Species
Types of centrifugal fans of snails are three positions, differing from each other in power. This parameter depends on the rotation speed of the electric motor, and therefore the rotor, as well as on the number of blades in the device design. Here are three types:
- Low-pressure volute fans, the parameter of which does not exceed 100 kg/cm². Most often they are used in ventilation systems apartment buildings. Install snails on roofs.
- Medium pressure models – 100-300 kg/cm². Installed in ventilation systems of industrial facilities.
- High pressure variety – 300-1200 kg/cm². These are powerful fan units, which are usually included in the air exhaust system of paint shops, in industries where pneumatic transport is installed, in warehouses with fuels and lubricants and other premises.
There is another division of snail fans - according to their purpose. These are primarily general purpose devices. Then there are three more positions: explosion-proof, heat-resistant and corrosion-resistant.
Restrictions on use
- with sticky suspensions with a concentration of more than 10 mg/m³;
- with fibrous materials in the air;
- with explosive inclusions;
- with corrosive particles;
- and in warehouses where explosives are stored.
In all other cases, snails can be used without restrictions. And one more point regulating the conditions of their operation is temperature regime which must not be violated: from -45C to +45C.
Popular models
In principle, there is no model-based division of snails. There are certain brands that are produced by all manufacturers. And they are divided mainly according to their intended purpose. For example, a VRP fan, where the letter “P” means that this is a dust model, which is used in ventilation and aspiration systems to remove air from high concentration dust. That is, this is a specific model that must be used for its intended purpose. Of course, this device can easily handle ordinary air, but it is more expensive than standard VR or VC, because its design uses thick metal to make the body and blades, hence the higher power of the electric motor.
The same applies to VR DU brand fans, that is, for smoke removal. They are made from more quality materials with installation of an explosion-proof motor. Hence their high price. As for other positions, VR is divided into types that have already been mentioned, and each group has its own models with its own technical characteristics.
How to make it yourself
The question posed by the title of this section can be classified as rhetorical. That is, in principle, you can make a snail with your own hands if you have the skills of a tinsmith or welder. Because the device will have to be assembled from sheet metal. And depending on the power and performance of the device, the metal will have different thicknesses.
Plus, making the blades yourself and attaching them to the rotor properly is difficult. Because the rotor will rotate at enormous speed, and if the balancing of the structure is upset, the fan will be torn apart in the first 20 seconds of operation. Yes, and you need to choose the right electric motor, taking into account the power and rotation speed, plus correctly connect it to the fan rotor. So don’t try to do anything with your own hands - it’s dangerous for your own life.
The body of the snail fan resembles the shell of this mollusk. This equipment is used in a number of industrial facilities, housing construction, and ventilation systems. The principle of operation is the force created by the rotational movement of the rotor blades; they penetrate into the inlet openings in the form of a snail, capture the air flow and drive it through the outlet openings. They are located at an angle of 90 degrees to the entrance hole.
Peculiarities
A good “snail” fan can be obtained with your own hands during the assembly process only if you know the design. The installation and impeller create torque for air movement. The need for an exhaust device increases when space is limited, so installation takes place with specialized equipment. The fan casing is made in the form of a spiral and serves to direct air.
Homemade fans of this type have become very popular lately. However, in the absence of skills and the necessary time, purchasing ready-made equipment will be one of the best options.
To create a “snail” in the inner part of the fan mount, you need to place a radial element - a wheel attached to the installation. The discharged space is created by the curved working blades of the wheel.
The air mass enters through the inlet pipe. The inlet pressure drops and draws in ambient air. As a result of the rapid movement of air in a spiral, the speed in the outlet hole increases significantly and high pressure is created. Air flows rapidly from the outlet pipe. If the pipe is on the left, then the rotor rotates clockwise, if on the right, then in the opposite direction.
When assembling with your own hands, the curvature of the “snail” blades used is taken into account.
Created Threads
Centrifugal "snails" - power taken into account in three positions.
Low pressure fans - no higher than one hundred kg/cm square. Temperature no more than 80 °C. Used when equipping production workshops and construction of houses. "Snails" are installed on roofs.
Models with average pressure - from one hundred to three hundred kilograms per square centimeter.
High pressure equipment - three hundred to two thousand kg/centimeter squared. High-pressure air flows from exhaust volutes are usually located in fuel combustion zones different brands in boiler rooms, in fuel and lubricant warehouses, in air duct systems of paint shops.
A centrifugal scroll fan requires reliable mounting and a solid base. In order to avoid vibration, the housing is properly fixed. Ignoring this phenomenon will cause the device to fail.
Do it yourself
The question is rhetorical, which requires the skills of a welder or tinsmith in the process. After all, assembly is carried out from metal sheets of various thicknesses.
Making the blades yourself, and then high-quality fastening to the rotor is quite difficult task. Indeed, if the balancing is imbalanced, the fan will shatter into pieces due to significant rotation of the rotor in the very first minutes of operation.
When assessing power and rotation speed, the electric motor is selected correctly. In this case, craftsmen use snails dismantled from equipment, vacuum cleaners and hoods. This serves as a guarantee for determining the power and parameters of the case.
Assemble the fan a “snail” for household needs in the workshop is possible, it will be a feasible task. In other cases, only factory-made fans are used.
Creation
Instructions for creation.
- Calculate the parameters and dimensions of future equipment. In this case, damper pads are inserted to avoid vibration during operation. These measures will help save the snail.
- Use of available materials in the manufacture of a fan housing made of plastic or plywood. When performing assembly work, make sure once again that there are no gaps and the seams are sealed.
- First you need to analyze the power circuits of the unit. Power is taken into account here. For high fan power, a belt drive is used. At low powers, a shaft and rotor-gearbox connections are used.
- Fastening elements are used, namely plates in the letter “P” for mounting on the body. A strong foundation is needed for powerful units.
A snail fan is one of the most popular devices that are used to create air flow with high densities. This hood has its own characteristics, design nuances and operating principle that distinguishes the snail from other systems.
Before you assemble a highly efficient snail fan with your own hands, you should learn about the features of this device and its design.
- To carry out forced air movement, sometimes you can get by with an impeller and a power unit that will rotate the working element;
- If space is limited, but an exhaust unit is absolutely necessary, specialized equipment comes to the rescue;
- The cochlea is a body made in the form of a spiral;
- The mission of the corps is to carry out the tasks of the air channel;
- Do-it-yourself snails are quite popular, but when there is no time to assemble or lack the appropriate skills, objectively the best solution will be the purchase of finished equipment;
- To create an air flow, a radial component - a wheel - is located inside the fan structure;
- This radial piece of equipment connects to the power plant;
- The blades on the impeller are curved, which allows them to create a discharged area when they move;
- The inlet pipe of the structure serves to supply air or another medium;
- Due to the movement along the spiral casing, the speed of air exiting through the outlet opening increases noticeably;
- Coil fans are available in heat-resistant, corrosion-resistant and general purpose;
- The movement of the volute fan blades depends on the design of the equipment. Special attention attention should be paid to the location of the outlet pipe. If it is on the left, then the rotor should rotate clockwise, or vice versa;
- When choosing or assembling a snail with your own hands, you need to take into account how many blades are used and what their curvature is.
Created air flows
When planning to assemble a homemade unit with your own hands or buy a ready-made snail-type exhaust apparatus, you should definitely take into account the characteristics of the air flows created. Namely, you should be interested in the flow value, on which the scope of application of the snail largely depends.
- Low pressure. Low pressure air flows are widely used in production workshop equipment and layout household appliances. The air temperature here is not allowed to exceed 80 degrees Celsius. Also, low-pressure snails are not adapted to work in aggressive environments.
- Average pressure. Medium pressure scroll fans are most often found in the layout exhaust system used for transportation and removal of fine materials. A striking example is grain and sawdust removal.
- High blood pressure. High-pressure volute hoods form air flows that flow to the combustion zones various types fuel. Boiler equipment, working on different types fuel, is equipped with high-pressure volutes.
A volute, or centrifugal fan, requires a reliable base. The housing must be properly fixed so as not to create vibration. Industrial units are characterized by increased vibration. If this phenomenon is not prevented, the device will gradually fail.
Do it yourself
Building a scroll fan is not the most difficult thing if you decide to take on a homemade unit with your own hands.
- Functional purpose. To equip a part of the room with a ventilation system, small area or equipment, the body can be assembled from scrap materials. If this is a centrifugal unit that will generate air flows to ensure the operation of boiler equipment, then the housing is made by hand using stainless steel or heat-resistant metal.
- Power. This parameter directly depends on the functions that the centrifugal unit will perform. Many home craftsmen use snails removed from old equipment, ventilation systems, hoods or vacuum cleaners. By using such a unit, you guarantee an exact balance between power and body characteristics.
If you want to make a snail for domestic use, or for use inside a workshop, then you can assemble the device yourself. All other situations imply the need to use only factory-proven, proven snails.
To assemble an effective homemade snail fan with your own hands, you will need to complete the following tasks:
- Calculate the dimensions of future equipment. If this is a centrifugal unit for installation on limited space, be sure to use damper pads. They will compensate for the vibrations generated during its operation and protect the volute from premature wear. If this is a large stationary unit, vibration protection occurs due to the weight of the equipment and its fixation;
- Make a fan casing. If you do not have a ready-made box that is ideal for the fan, use improvised materials. Plastic is suitable for these purposes, plywood sheets, steel. If you decide to take sheets of plywood, make sure that during the process of assembling the structure there are absolutely no gaps and all seams are properly sealed;
- Think over the diagram of the snail's power unit. The job of the power plant is to rotate the fan blades. When choosing, consider how much power the snail has. If it is a centrifugal fan high power, use a belt drive. IN small installations it is important to use a shaft that connects the motor gearbox to the rotor;
- Use fasteners. When installing a scroll fan on the outer casing of the structure, use U-shaped mounting plates. If the power of the units is impressive, then be sure to adopt a massive, durable base;
- Minimize noise. A high-power volute is characterized by the fact that such a centrifugal fan emits quite a lot of noise. Objectively best way protect yourself from snail noise by assembling the equipment as efficiently as possible. After assembling the cochlea, it is problematic to compensate for the noise. The noisiest models are those whose body is made of plastic and metal. Wooden cases reduce snail noise, but are significantly inferior to their metal and plastic counterparts in terms of service life.
According to the presented diagram, you can create centrifugal exhaust devices of various power purposes with your own hands. If necessary, you can make changes to the circuit, change components, add auxiliary elements.
The most significant point when assembling a fan with your own hands is the reliable sealing of all seams in the structure and the protection of the engine itself. Over time and with use, an engine that does not have proper protection can become exposed to various debris, dust, dirt and moisture. It is no secret that this leads to wear, gradual destruction and failure of equipment.