The Vibratory Tray Dosers series VF, VFW and VFY are machines particularly suitable to dose free flowing and non-hygroscopic products with great regularity and accuracy. 

The Vibratory Tray Dosers can be generally used to dose granular products, pellets, flakes, fibers until dimensions of 20mm and over. Among them there are for example granular and pellettized techno-polymers, fiber or microspheres mineral fillers, typically used in the compounding plastic industry; and also raw cereals or flakes, various seed, dried or dehydrated fruit, spices in grains or ground leaves, that are variously used raw materials in the food industry. 

With the Vibratory Tray Dosers VF, VFW and VFY fine powder products can be dosed as long as they are low moisture content, averagely flowing and have a angle of repose not less than 30°.

The dosing tool is constituted by a horizontal duct having the shape of a channel with the proper geometry to hold the product to dose. The channel is mounted on a linear vibrator which creates an high frequency oscillatory motion which pushes the product forward in a linear and regular way. 

The resulting product flow is just as regular and the throughput is function of the intensity and the frequency of the vibrations. The dosing trays are carpentry made. They can have various dimensions and shapes, typically “U” or “V”, that are defined according to the product to dose and the performances requested. 

The dosing tray is protected by a covering carter which prevents from the accidental entrance of foreign matter falling from above. 

The dosing tray is fed by a vertical duct which makes the product come down by gravity inside of it. The duct has a gate whose opening is manually adjustable and by which the bed height of the product can be varied on the channel. With this operation the product flow width to dose is adjusted in order to match the capacity range between the minimum and maximum values demanded. 

The Vibratory Tray Dosers have the prerogative not to damage the product as they do not have moving mechanical devices, as it happens with the screw dosers. 

They are preferred when dealing with particularly fragile products or more in general when their original particle size has to be preserved. 

Another key aspect is the regularity of the dosing flow. The product is evenly distributed on the dosing tray and it comes out the doser with a waterfall flow having a regular and constant section, as opposed to what happens with dosing screw tools which creates instead a pulsing flow due to their conformation and their rotary motion. 

The linear vibrators are available in different sizes and types. The choice is based on the flow rates requested and the product characteristics. 

The types of vibrators adopted are basically two and they are characterized by a different constructive technology. In particular are used electromagnetic linear vibrators and resonant piezoelectric vibrators. 

The linear electro-magnetic vibrators are the most used in continuous dosing. The resonant piezo-electric vibrators are used in the batch accurate dosage also for quantity of few grams. It is possible to grant the accuracy of about one gram even for batch dosages with short cycle time of a few seconds. 

The linear electro-magnetic vibrators are available also Atex certified. 

The linear vibrators are controlled by specific electronic drives that allow to adjust the intensity and frequency of the vibration. In this way it is possible to regulate the conveying speed of the product in the dosing channel in order to obtain the wanted capacity in a minimum and maximum predefined range. In most cases it is possible to have an adjustment range of 1 to 50 between the minimum and the maximum. 

The entire range of Vibratory Tray Dosers is constituted by 4 standard sizes that allow to cover a capacity range from a minimum of 0,1 kg/h to a maximum of 5.000 kg/h. 

It is possible to associate to the dosers a wide variety of standard loading hoppers with different potentials. 

The hoppers can have a polygonal or truncated conical, symmetrical or skewed shape and their design ensure a correct out flow and complete emptying even with poorly flowing products. The polygonal hoppers have rounded corners to allow a complete and easy cleaning; they can be equipped with wide transparent polycarbonate sight glasses and inspection window as needed. The hoppers truncated conical shaped can have a vertical agitator, which is useful for particularly compact products, that stick to the walls and have to be forced to come down the dosing body. Agitators with different geometric shape are available to chose according to the product characteristics. 

The hoppers can be manually or automatically loaded. 

The hoppers loaded manually have a completely removable lid or semi-openable with hinges. Inside it there is a safety grid which protects from the risk of contact with moving parts of the doser and prevents the accidental access of foreign matter that could damage the doser. 

The hoppers automatically loaded have bolted lids with a round inlet and a vent socket equipped with a bag in polyester filtering fabric sleeve. 

As accessories of the hoppers there are level sensors, to detect the presence of product, and pneumatic vibrators or moto vibrators to prevent the formation of bridges. The most used sensors are capacitive types, rotary level sensors, vibrating level switches to choose according to the product characteristics. 

In the gravimetric version, the doser can be installed on a proper platform scale(VFW) or hung to load cells with its hopper (VFY). The load cells are off-center or flexion type, made in aluminium or in stainless steel with protection grade up to IP67, available also with Atex certification when requested. 

The most used construction materials are stainless steel Aisi 304 and 316L. 

The surfaces in contact with the product can be easily pickled or mirror polished in case of poorly flowing products. It is possible to have certifications of the contact materials on request. 

The outer surfaces are satin finished 180 mesh. It is possible to have them glass bead blasted or electro-polished on request. 

The gaskets are made in dust-tight rubber , such as SBR or NBR. They are available also with FDA certification on request. 

Both volumetric VF and gravimetric VFW and VFY dosers can be Atex 21/22 and Atex 21/21 certified. 

Electrical control panels can also be supplied including software specifically designed accordingly to the requested functionality. 

A particular variation of this machine range is constituted by the Vibratory Tube Dosers series VT, VTW and VTY. 

The substantial difference is in the dosing device that is constituted by a vibrating tube instead of an open vibrating channel. This arrangement is particularly suitable to dose fine powders because it allows to improve the dust tightness of the entire doser preventing it to come out in the environment. 

Vertical T spouts complete the set of this kind of dosers, they are mounted at the end of the vibrating tube to vertically guide the product falling down while dosing. Discharges equipped with automatic plug, slide or butterfly valves are also available. These devices have the function to intercept the product while falling down. In the batch dosages they are particularly suggested to obtain the maximum accuracy and in general to avoid the spontaneous product leakage, specially if very free flowing , when the doser is on break. 

The vibrating tube, because of its closed mechanical conformation, is a very stiff dosing device and few reactive to changes of the vibration frequencies. 

Consequently, the Vibratory Tube Dosers do not allow a very wide regulation range. Normally they are used to work at a specific flow rate, which is the data from which have to be determined the dimension of the dosing tube and the setting of the electronic controller. 

In the gravimetric version, the doser can be installed on a proper platform scale (VTW) or hung to load cells with its hopper (VTY). The load cells are off-center or flexion type, made in aluminium or in stainless steel with protection grade up to IP67, available also with Atex certification when requested.