In order to mechanize this process and make the work easier, a mechanical device with an electric drive can be made. Such a mechanism will be especially relevant if it is necessary to prepare large quantities of building mixtures from bulk materials.
Such a device is called a vibrating sieve or vibrating screen. It has a fairly simple design, and therefore it is not difficult to make a vibrating sieve with your own hands.
General design
Making a vibrating screen for sand or crushed stone does not require a lot of time. The design description of the vibrating sieve includes the following elements:
- supporting frame on which all other parts and assemblies are located and secured;
- electric drive, which can be used as a power saw, jigsaw or drill;
- an external box (frame) without a bottom, mounted on fixed furniture casters;
- guide rails made of metal corners for moving rollers along them;
- nestable box with a metal mesh bottom;
- a chute for transporting sifted material to a collection bin;
- a device for adjusting the rotation speed of an electric motor.
The transport chute is easiest to make from plywood, but a metal structure will be much more reliable, especially when sifting gravel or other coarse materials.
A device for adjusting the rotation speed may already be provided in the design of an electric drill or jigsaw. In this case, a separate external regulator will not be needed.
The principle of operation of a vibrating sieve for bulk materials is to transmit translational movements from a power tool to a frame with a fixed sieve. After sifting the materials, the internal wooden frame with the sieve is raised and unnecessary screenings are dumped.
Is it necessary to sift sand?
In construction and in the production of concrete products, sand must comply with the requirements of GOST 8736-93. It follows from it that grains with a fraction of up to 0.14 mm should not exceed 10% of the total mass, from 5 to 10 mm - no more than 5%, and grains larger than 10 mm should be completely absent. The bulk should include grains ranging from 1 mm to 3 mm. To achieve such homogeneity, river or quarry sand must be sifted.
For other areas where sand is used in its pure form, for example, for landscape design (decorating paths and ponds) or agriculture (loosening the soil), purified material with a fraction of no more than 0.6 mm is also used.
For mortar/brick laying
Using cement mortar, you can lay brick, stone, or fill joints on walls; the reliability of the building will depend on the quality of the sand. For long-lasting installation, the solution must be homogeneous, so the sand must be sifted to remove large inclusions.
For concrete
For the production of concrete, coarse sand with a fraction size of up to 2.5 mm is used. Preference is given to river sand, since it does not contain clay and its grains of sand are round in shape - sea sand is similar in properties, but contains salt that needs to be washed out. But the quarry contains a large amount of clay and stones, so it must be washed and sifted. This type is in mass demand due to the low cost of production; in production they use quarry sand and sift it themselves - this is the best option.
For plastering walls
For repair work, clean sand with a fine fraction must be used; any heterogeneity of the plaster will affect the finishing layer and will be visible on the walls. River water is most often used because it is the cleanest environmentally. In addition, the particles have a rounded shape, which has a beneficial effect on the uniformity of the finished mass.
For sandbox
For sandboxes, calcined quartz sand or sifted river sand is better suited. It is cleaned of shell fragments and small pebbles. It is optimal to use soft, loose sand with a fraction of 0.6 mm - if the grains are larger than 2 mm, it will be too crumbly. The basic requirements for children's sandboxes are:
- it is necessary to use dry, environmentally friendly and safe river sand;
- It is allowed to use washed quarry sand, which does not contain dirt, clay, gravel, stones and shells.
Necessary materials
To make a frame, two drawers and other elements of the mechanism, you will need:
- wooden blocks 60x70 mm;
- plywood 20 mm thick;
- 6 rubber or spring shock absorbers;
- 4 or 6 furniture casters with mounting frame;
- piano loop with a length of at least 500 mm;
- metal corners for guide rails;
- metal plates or strips to strengthen wooden structural parts;
- screws, bolts and nuts.
Dimensions of main structural elements
Before starting to assemble a sand vibrating screen, it is recommended to draw an assembly diagram or a simple assembly drawing. This will simplify the assembly work and help determine the order in which they should be performed.
Recommended dimensions of the supporting frame (base):
- length 1400 mm;
- width 600 mm;
- height 850 mm.
The length of the outer box without a bottom should be equal to half the length of the supporting frame. The width is 100 mm less than the width of the base, the depth is at least 120 mm.
The dimensions of the inner box with a mesh bottom should ensure its easy removal from the inner frame for free overturning and release of accumulated waste. The outer and inner boxes are connected along the short side with a piano hinge, as a result of which there is the possibility of lifting and tilting the inner structure.
How to quickly sift sand in large quantities?
In production, the amount of sand consumed can reach several tons per week. If you sift it manually, the process will take a month, or even more. Therefore, special equipment is used, which speeds up the production process of concrete products several times. One vibrating sieve is enough for one casting line.
Assembly order
The production of a vibrating sieve begins with the assembly of a supporting frame from wooden blocks in accordance with the drawing.
To increase the strength of the structure, it is recommended to make connections of wooden parts with reinforcement with metal corners and plates. After this, guide rails must be secured to the inside of the base frame as a support for the movement of furniture rollers. The guide angles are fastened together into a single structure using transversely installed wooden blocks. To reduce vibration levels during operation, 6 or 8 rubber shock absorbers must be installed between the corners and guides.
To secure the drive for a vibrating sieve made from an electric drill, jigsaw or saw, on one side of the upper part of the support frame it is necessary to provide a platform corresponding to the size of the power tool.
After the support frame is assembled, a plywood gutter is made and installed. The processed material will flow through it into the collection container. A metal gutter is more difficult to make, but it will provide a longer service life.
Is it profitable to make a concrete mixer with your own hands?
Practice shows that homemade products are profitable if there are “unnecessary” electric motors, pulleys, chains, gears, metal, etc. A used 200-liter barrel costs a penny, but its bottom will have to be strengthened and the top of the barrel will have to be narrowed to a cone. A “pear” made from a barrel, due to its thin walls, is inferior in strength and durability to a high-quality factory one made of thick metal. Do not forget to add to the cost of the concrete mixer the time spent on its manufacture and, if not, the cost of purchasing the necessary materials and tools. Therefore, first study the construction market and the offers of private owners.
Do you want to buy a concrete mixer, but don’t know which one to get so that it lasts a long time and doesn’t break? The answer is in the topic Choosing a concrete mixer, where the practical experience of real users is collected and manufacturers of concrete mixers provide advice.
The video Concrete and Concrete Mixes tells where it is better to buy concrete, and what ingredients and additives are needed to make it yourself.
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Oscillation speed control unit
Manufacturers of power tools produce models with or without the ability to adjust the motor speed. In the second case, the oscillations of the electric saw may be too frequent, and an additional external device for adjustment will be required.
A rheostat-type regulator can be purchased at electrical supply stores. At the same time, it is recommended to buy a circuit breaker, which will provide additional protection for the tool and its long-term operation.
As a result, you will be able to provide any required vibration frequency of the working boxes of the vibrating screen, depending on their load and the weight of the material being processed, without overloading the electric drive.
Drying
Drying sand is necessary, for example, when making dry mixtures. The drying method depends on the moisture content of the original material, its volume, required productivity and available means. For example, when the volume of wet sand is small and the day is hot, it is dried by spreading it in a thin layer on a flat base. A good option is sheet iron or corrugated board. Thus, drying methods can be divided into categories:
A popular method of preparing material for mortars (especially in dry mortar factories) is the use of a “vibrating fluidized bed drum screen”. This is a modification of the drum seeder in which the mesh is located only at the end of the pipe. At the beginning of it, a gas “gun” with a powerful fan is installed. This article will tell you about the sand fraction coefficient according to GOST 25584-2016.
An electric dryer differs in that heating is produced not by burning gas, but by electric heating elements.
