Performance features
The film evaporator is provided with the following unique features,
which are incomparable with other conventional film
evaporators:
1. Very low pressure loss
2. Operation under vacuum can be realized in a
real sense
3. High heat transfer coefficient and high
evaporation intensity
4. Low temperature evaporation
5. Short flow passing time
6. Low grade steam can be utilized
7. Strong adaptability and convenient
operation
8. Jacket pressure: normally designed according
to 0.4Mpa steam, or designed according to user requirements. When
heat transfer oil is adopted, other design can also be made.
9. Vacuum degree inside evaporating cylinder:
normally designed according to *0.*9Mpa (about ***0mmHg), or
*0.**5Mpa (about ***0mmHg) and *0.***6Mpa (about ***0mmHg) can also
be designed according to user requirements.
*0. Materials of main cylinder (parts that contact materials)
and jacket: carbon steel, SUS**4, **6L, **6Ti, **0S, titanium,
nickel, etc. can be adopted according to actual conditions and user
requirements.
It is widely applied in chemical industry, petrochemical industry,
medicine, fertilizer, daily chemicals, food, fine chemical
industry, etc.
It is widely applied in chemical
industry, petrochemical industry, medicine, fertilizer, daily
chemicals, food, fine chemical industry,
etc.
Structural features
1. Motor and speed reducer.
It is the driving unit for rotor rotation. The rotating speed of
rotor depends on the form of scraper, material viscosity and inside
diameter of evaporating cylinder. The selection of a suitable
linear speed of the scraper is an important parameter to guarantee
stable and reliable operation of the evaporator and satisfactory
evaporating effect.
2. Separating barrel
The materials enter the evaporator through the inlet at the bottom
of the separating barrel, and are continuously and evenly
distributed on the evaporating cylinder by the material spreader
installed inside the separating barrel. The secondary steam
evaporated from the evaporating cylinder rises to the separating
barrel. After passing through the gas-liquid separator inside it,
the liquid drops or bubbles that may be carried by the secondary
steam are separated, and the secondary steam will be discharged out
of the evaporator from the outlet at the top.
The reasonable design of the separating barrel based on the
calculation of resistance inside the evaporator is one of the key
factors that avoid short circuit of materials. (The so-called short
circuit means that the materials leave the evaporator at the
secondary steam outlet before the evaporation process is
completed).
3. Material spreader
The material spreader is installed on the rotor. Through reasonable
design, the materials entering the evaporator from the tangent
direction are continuously and evenly spread on the evaporating
surface by the rotary material spreader.
4. Gas-liquid separator
The rotary vane type gas-liquid separator is installed at the top
of the separating barrel. It is used to collect liquid drops or
bubbles that may be carried by the rising secondary steam and make
them drop back onto the evaporating surface.
5. Evaporating cylinder
It is also called heating cylinder. It is the evaporating surface
where the materials that are subject to forced film forming by
rotary scraper and the heating media inside the jacket carry out
heat exchange. The inside diameter and length of the evaporating
cylinder are determined by the evaporating area and appropriate
length-diameter ratio.
6. Rotor
The rotor installed inside the evaporating cylinder is composed of
rotary shaft and rotary bracket. Driven by motor and reducer, the
rotor drives the scraper to make circular motion. The rotary
bracket is made of stainless steel precision castings, so that its
strength, geometrical dimensions, stability, etc. are effectively
guaranteed.
7. Scraper
Due to the movement of the scraper, the materials are constantly
scraped into films on the evaporating surface,so as to achieve the
effect of film evaporation.According to material viscosity, the
following three kinds of scraper forms are available for
selection:
(1) Sliding scraper
The sliding scraper is the most basic and common scraper form. The
scraper is installed inside the four scraper guide grooves of
rotor. Under the effect of centrifugal force due to rotor rotation,
it is radially thrown to the inner wall of the evaporating
cylinder, and make circular motion together with the rotor. This
scraping of the scraper makes the materials under the status of
membranous turbulence on the evaporating wall and greatly enhances
heat transfer coefficient. In addition, the continuous scraping can
effectively avoid the occurrence of overheating, dry wall, scaling,
etc.
Generally, the scraper adopts filled PTFE. The end machining of the
scraper is provided with liquid guide groove of certain
angle.
(2) Fixed scraper
The fixed scraper is made of metal materials. It is rigidly
connected with the rotor. The length of the scraper is the same as
that of the evaporating cylinder. The interval between the rotary
scraper and the inner wall of evaporating cylinder is only **2mm.
Higher machining and installation precision is required. It is
suitable for evaporation, concentration, precipitation and
purification of materials of high viscosity and those easy to
produce bubbles.
(3) Hinge scraper
The scraper is suitable for materials that easily form scaling on
the heating surface. The scraper is generally made of metal parts.
The scraper is installed on the rotation bracket by adopting the
flexible hinge. When the rotor turns, under the effect of
centrifugal force, the scraper is tightly pressed at the inner wall
of evaporating cylinder, and slides at certain angle (with the
wall) to scrape the materials into films, and scaling on the wall
is avoided.
8. Bottom head
The individually designed W model bottom head is provided with the
high temperature resistant self-lubricating bearing, which not only
facilitates material discharging, but also makes maintenance and
servicing of bottom bearing convenient
