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An explanation of Distillation Terminology
Identification & abbreviations:

Distillation units with tilting boiler: residue unloading by means of mono-use bags "Rec Bag" (for solid contaminants) or tilting the unit (liquid contaminants).
In the event of solid contaminants, the concentration of the process residues inside the bag is excellent: a solid cake which is easy to dispose of.

Distillation units with tilting self-cleaning boiler equipped with scraper having adjustable metallic blades for the highest concentration/drying of the process residues.
Keeping in movement the product to be treated we obtain the complete separation between solvent and contaminants, for the highest yield of distillation. An automatic drying cycle allows the residues to be extracted as a powder.
Discharge by tilting the plant.

S = Water Splash Proof
Distillation units with water splash proof electrical protection, normally used for treating Not Inflammable solvents ; they can be utilized for the distillation of Inflammable solvents in those Countries where the local rules allow it.

D = Explosion Proof
Distillation units with explosion proof electrical protection, EEx od IIB, for treating Inflammable and Not Inflammable solvents, able to operate in the maximum danger zone (zone 1).
Zone 1 is the area of the factory with the highest explosion risk: stock of solvents and other inflammable material.

V = Vacuum distillation
The vacuum distillation is suitable for :
-distillation of solvents with boiling temperatures higher than 160-180C
-distillation of inflammable solvents with auto-ignition temperature close to the boiling temperature
(E.g. : White Spirit =boiling temperature 150-190C
auto-ignition temperature 254C
the temperature of the diathermic oil which heats the boiler is close to the auto-ignition temperature of the solvent, so it must be distilled under vacuum)
-treatment of thermolable solvents (chlorinated solvents generally) and/or thermolable contaminants (e.g. products formulated with nitro-cellulose) to avoid their decomposition (acidification, auto-combustion without flames, etc.)
Auto-ignition temperature : temperature at which solvent vapors catch fire without any external intervention.
Flash point: temperature at which the solvent vapors catch fire by intervention of an external source (fire).
V1 = Pneumatic Vacuum Group
Combined with the distiller, allows distillation under reduced pressure ; it is composed of :
-Pneumatic Vacuum Generator  with tank for solvent unloading
-Pump fed by compressed air, which exploits the Venturi effect
-Pneumatic vacuum switch with air economizer for optimizing compressed air consumption
-Automatic vacuum starting control with solenoid valve
Nominal vacuum degree : mmHg 560-580
The valve (with water splash proof or explosion proof electrical protection) is attached to the distillation unit. The timer gives the start to the unit and to the solenoid valve, which controls the opening and closing of the compressed air.
Connections :IN=to compressed air inlet
OUT=to tank
The vacuum group can also work without the solenoid valve ; in this case opening and closing of the compressed air must be performed manually. This is the case when a customer, who already has an atmospheric pressure distillation plant, not arranged for the vacuum, needs to distill under vacuum. The vacuum group can be supplied without sending back the unit to Formeco for installing the solenoid valve.

V2 = Vacuum group with liquid ring pump
Vacuum group equipped with liquid ring pump, made of stainless steel AISI 316, fed in closed circuit by the solvent in treatment, complete with feeding tank for the pump with exhaust gas condenser.
Nominal vacuum degree : mmHg 580-620.

V3 = Vacuum group with electrical lubricated vane pump
Vacuum group with electrical lubricated vane pump. Normally it is utilized for units of the series "Professional" (60-120-180 litters).
Nominal vacuum degree : mmHg 600-650.

V4 = High vacuum group
Complete group with electrical lubricated vane pump for high vacuum.
Nominal vacuum degree : mmHg 750-756.

M = Fixed boiler
Distillation units with fixed boiler and manual or automatic valve on the bottom of the boiler, suitable for treating liquid or semi-liquid process residues.

R = External heating source
The industrial plant can exploit an external heating source, provided by the customer (hot water, steam, diathermic oil circuit).

E = Azeotropic distillers
Azeotropic distillation plant with steam injection (see brochure).

Q = Self-cleaning boiler
Distillation units with scraper having adjustable metallic anti-spark blades (see entry "DYnamic").

T = Agitator
Distillation unit with agitator inside the boiler. It is different from the scraper because the motor is placed on the top (and not on the bottom) of the shaft. It is used when it is necessary to keep in movement very dense products, getting a process residue which will be a semi-liquid.
... = Counter blade
Counter blade placed on the shaft for smashing possible blocks of residue during the final drying phase. For products which are potentially not crumbly we advise to use the additive "Tix Dry".

Tix Dry = Drying additive
To obtain a dry process residue with potentially not crumbly products, we advise to use the additive Tix Dry which will be useful to break up difficult drying residues.
The additive must be introduced in the boiler before starting the distillation process, in percentage variable between 1 and 3% of the overall weight of the liquid to be treated.

... = Geometrical capacity and loading capacity of the boiler
The geometrical capacity is the overall volume of the boiler, indispensable for calculating the effective loading capacity.
Formeco identifies with the identification symbols the effective loading capacity.
The maximum loading level is indicated by a mark in the inner wall of the boiler.
For example: we boil 3 litters of water using a pan of 4 litters. During the boiling phase we shall get a overflowing of water from the pan.
To make up for it we must :
-take out some water ; but this solution does not allow to boil the prearranged quantity
-reduce the intensity of the flame ; in this case the duration of the boiling process will be longer
-replace the pan with another one larger. Choosing this solution we can boil the amount of water in the shortest time possible.
In the distillation process we see the same phenomenon.
So, volume of the boiler and installed power are two fundamental parameters for choosing a distillation unit ; reduced volumes and power will produce, inevitably, lower performances.
A correct sizing of the plant is characterized by :
-Maximum loading capacity not higher than 70% of the total boiler volume
-Installed power not lower than 80 Watt/litre.
The eventual comparison with units built by competitor companies must be effectuated on the effective loading capacity of the plant, paying attention therefore to the total volume of the boiler, which must have the above characteristics.
E.g. :Formeco D 12 A loading capacity 12 liters - Total boiler capacity 19 liters
Formeco D 60 A loading capacity 60 liters - Total boiler capacity 90 liters

A  - Ax = Air condenser
Vapor condenser made of Copper (A) or Stainless Steel AISI 304 (Ax) cooled by air with a ventilation fan.

W - Wx = Water condenser
Tube bundle condenser, made of Stainless Steel AISI 304 (Wx) or AISI 316 (Wx1), water cooled.
Feeding in open circuit, automatic feeding/stop of cooling water, arranged for possible connection to a chiller for cooling the condensation unit in closed circuit.
We advise to use the water condensation unit to distill solvent with a low boiling temperature (acetone) in an ambient with high temperatures up to 40C, and with solvents with boiling temperature lower than 50C.

P1 = Diathermic oil forced circulation
Diathermic oil forced circulation, peripheral to the boiler, to optimize the thermal exchange, increasing the production of the plant.

P = Diathermic oil heating unit with pump
Diathermic oil heating unit (for industrial plant only) with the same function as pump P1.

C1,2,n = Automatic loading
The distillation units arranged for the automatic loading of solvent are equipped with level controls inside the boiler.
C1 for 1 batch
C2 for 2 sequential batches
Cn for multi-batch

Optional for automatic loading plant:
-Pneumatic or vane pumps
-Electronic microprocessor for regulating the process phases

Two consecutive batches are slower than one continuos cycle but, on the other hand, avoid the possible development of foam generated by the continuos loading of cool solvent on top of hot solvent.

U = Distillation unit with unloading valve
U1 Manual valve for the process residue unloading (liquids or semi-liquids), placed on the bottom of the boiler.
U2 Automatic bottom valve
U3 Automatic bottom valve for solid residues.

F = Pseudo-fractionating distillation
Three-way valve for distilled solvent deviation. It allows the pseudo-fractionating of two distinct solvents, characterized by different boiling temperatures (minimum range 30C).
Working on the temperature, the valve automatically changes the distilled product from one collecting tank to the other.
This kind of distillation is used, generally, in the medical field (pathology labs) for dividing alcohol from toluene / xylene and in wood furniture factories for separating acetone from other fractions of solvents which are contained in the paints.
The thermostat, with fixed temperature for solvents with low boiling temperature, is placed inside the electrical box. This temperature can be changed opening the same electrical box. The working thermostat, outside the box, must be set at the boiling point of the higher boiling solvent.
E.g. :acetone + solvent with high boiling temperature
fixed thermostat75C
working thermostat Distillation=120C
working thermostat Drying=180C

G = Distillation units with double power
These are specific units for recycling antifreeze liquid (normally 50% water and 50% glycol ethylene) equipped with double power in comparison with a normal solvent distiller.

C = Distillation/Concentration units
Special models of 12 and 25 liters units. All their components in contact with solvent are made in stainless steel AISI 304, equipped with a 24 hours working timer for treating small quantities of dirty water. The distillation takes place at atmospheric pressure.
While the evaporation of 1 liter of solvent generally needs from 50 to 150 kcal, for the evaporation of 1 liter of water we need 540 kcal. Using the same power, the distillation will be slower and, consequently, we have to set the timer at a longer cycle (normally 8-10 hours are enough).

AFN1 = Safety device for nitro-cellulose
This device is composed of a temperature detector inside the boiler which opens a water jet if the temperature reaches the previously set value (see technical sheet nitro-cellulose).
Normally the working thermostat is set at 100C. Inside the electrical box there is another thermostat, normally set at 115C, with the sensor placed in the inner neck of the boiler. If this temperature is reached, the solenoid valve opens the water shower for a previously set time.

AFN2 = Safety device for nitro-cellulose with photocell
Extinguishing group with photocell which notices the formation of smoke inside the boiler and the condensation unit, opening immediately a water jet inside the boiler, for a previously set time (see technical sheet nitro-cellulose).

...= Caution Safety device for nitro-cellulose
In case of possible presence of nitro-cellulose in the contaminants, we can utilize the electronic card HSE 956 for regulating the distillation batches as to avoid any possible combustion.
E.g. :distillation cycle at atmospheric pressure + vacuum drying cycle
After the distillation cycle the plant is cooled for about 45 minutes disconnecting the electrical resistance. At the end of the drying cycle, the vacuum works for other 45 minutes, as to avoid that the temperature exceeds the safety limit.
This system is certainly less secure in comparison with the AFN devices : it represents an economical alternative if by chance the product to be treated contains low concentrations of nitro-cellulose.

SP = Quick cooling systems
SP1  This device allows a quick cooling of the diathermic oil, to perform a quick sequence of distillation cycles.
SP2  This device allows a quick cooling of the diathermic oil, to perform a quick sequence of distillation cycles ; it is equipped with an air-cooled or water-cooled heat exchanger
SP3  This device allows a quick cooling of the diathermic oil, to perform a quick sequence of distillation cycles ; it is equipped with a forced circulation pump for the diathermic oil.

Icf = Cartridge filter
Interchangeable cartridge filter, with quick inspection, placed above the aspiration pipe of the distiller ; this is an optional on the Azeotropic vacuum units.
Safety :

Boiler cover
The boiler cover acts as safety over pressure valve, being locked by a lid locking device with spring which opens at 0,1 bar of overpressure.
The other producers place a small valve on the top of the cover, which can easily become obstructed during the distillation process due to foam formation.
Formeco distillers have a special lid locking device (with spring) to avoid pressure buildup in the boiler during the distillation process (at atmospheric pressure).
In distillation equipment of other constructing companies, we can have pressure buildup (making it necessary to lock the lid) when the vapors do not find a easy way to the condenser ; this can happen because the condensation unit and its pipe are too small.
Please note that in the event of blocking of the condenser and the vapors do not find a way out through the cover (or trough the valve, which is obstructed), there is a serious danger of violent expulsion of solvent from the cover, which is the weakest part of the plant.
Furthermore a deformation of the boiler can occur and consequently a possible contact of solvent with hot diathermic oil contained in the jacket around the boiler, thus forming a serious fire-hazard.

Working temperature Thermostat
This instrument regulates the working temperature of the plant, by means of a sensor inside the diathermic oil around the boiler.

Safety Thermostat
This instrument is connected to a sensor inside the diathermic oil regulated at a fixed temperature and it intervenes in the event of malfunctioning of the working thermostat.

Safety Thermostat at the outlet of the condenser
This instrument measures the temperature of the outflowing distillate. If, for malfunctioning of the condenser (ventilation fan out of order) the distillate should be at a higher temperature than the temperature set on the safety thermostat, the plant stops automatically.
In this way we avoid than not-condensed solvent vapors go into the atmosphere.

Regulating controls outside the electrical box
The regulating controls placed outside electrical box allow to adjust time and distillation temperature (and drying temperature) in a quick and safe way.
Some manufacturers, choosing for a more economical way, place this controls inside the electrical box, obliging the user to open and close the electrical box every time they want to change the distillation parameters.
On the market exist electrical boxes without holes foreseen of temporary certification; if the manufacturer makes a hole in these boxes, the same boxes must be certified another time.
Formeco has had certified all the electrical boxes mounted on the different units. The new certification (which is obligatory) is an expense for the company, a high expense that some manufacturers prefer not to undertake.
It is clear that a non-certified electrical box compromises the explosion proof construction of the whole unit.
We want to underline that it is bad habit of many users, who work with these units with inner controls, not to shut the electrical box after the setting (in order to avoid the tedious work of having to open and close the electrical box with all the bolts every time they want to change time or temperature parameters) : it means working in a very hazardous condition because the electrical box in this way can not guarantee any explosion-proof protection.

Emergency stop of the scraper inside the boiler
In the units of the DYnamic series, a push button placed near the opening of the boiler acts as emergency stop for the scraper.

Warning Lights in the standard units
h=Electrical resistance on (turns off when the machine is in temperature)
=Unit on (turns off at the end of the cycle)
The third warning light switches with the resistance in the explosion-proof units, while in the water splash proof units it works on the on the working timer at the end of the cycle.

Emergency Stop control
A push button, placed on the "Professional" series (60-120-180 liters) and in every industrial plant, allows the immediate stop of any operation of the machine.

Safety devices for contaminants formulated with nitro-cellulose
The definitive configuration of this kind of plant is designed by Formeco Technical Office (see the specific item of the legend). Normally we foresee one part of the cycle at atmospheric pressure and the final part under vacuum with cooling of the boiler by SP devices (see the specific item of the legend).

The following norms are applied in the construction of distillation units : CEI 64-2 and EN 50014-15-18. The self-certification CE is a good thing, better if accompanied by a certification issued by a recognized institution.
In Italy do not exist recognized labs for conformity certifications ; Formeco addressed to TV in Germany and in Austria, to Asev in Swiss, to Sei in Sweden and, more, to PTB in Germany.
The construction logic of Formeco:

Formeco does not perform just a simple sample test of their units. Any unit is tested in the factory before its delivery, making a complete distillation cycle with water.

Boiler diameter
The boiler is characterized by a large diameter and a shallow depth, so it can be easily accessed by the user during the cleaning and maintenance operations.

Boiler Cover with Economizer
In the units of the "Professional" series (60, 120, 180 liters), the inner part of the cover is equipped with a gutter-pipe, placed in the middle, to convoy the solvent vapor that condenses on the cover directly to the condensation pipe, avoiding reflux into the boiler which would diminish distillate production.

Process residue unloading
The cleaning has always been considered the hardest and most tedious operation when using distillation equipment. This problem has been solved by using "Rec Bags".
In the units equipped with scraper inside the boiler, the operation unloading will consist only in the  easy tilting of the unit, where the height of the opening of the boiler is designed in a way that the user can easily access it.
The "Professional" units (30-60-120-180 liters) and the industrial plant are equipped with a gear reducer to facilitate the tilting of the unit. It is an indispensable instrument for large size units.

Diathermic oil duration
The boiler is heated by electrical resistances immersed in diathermic oil. The right positioning and the right dimension of the oil expansion vessel of the heating circuit permits that the temperature of the oil surface in contact with the atmosphere does not exceed 60C. Above mentioned facts, together with the right design of the specific power of the resistance, allow to prolong the lifetime of the heating oil up to 2000 working hours.
Please note that the European Norm EN 50015 foresees an immersion stick or a transparent visual tube for the level control of the oil.
The same norm states also that "the construction must be made in such a way as to avoid efficiently any pollution of the oil with powder or moisture coming from outside, and also as to avoid that gas and vapors developed by the oil can go out freely". Therefore, units manufactured with a boiler immersed in oil do not respect this safety norm.
The oil level control stick has to be read in the following way :

Motor shaft gaskets lubricated by oil and compressed air
In the "DYnamic" units this lubrication avoid that solvent can go into the rotating parts of the mixer device, guarantying thereby a long duration of the gaskets and of the mechanic components of the shaft.
The lubrication is effectuated with compressed air and oil (contained in the small glass near the boiler). We recommend to check the oil level periodically.

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2011 Sawyer and Smith Corporation
Last modified: Tuesday July 08, 2014