Such countless stories have been told with regards to channel presses. Notwithstanding, numerous companions actually have migraines regarding how to unequivocally pick a channel press that suits their necessities.
Deciding the necessary channel region of the channel press as per the filtration task needed for creation is an issue frequently experienced by specialists and experts. The plate and edge channel press has a high working tension, solid flexibility to the separating material, and a straightforward design for simple activity, making it a generally involved sifting hardware in modern creation. The activity of the plate and edge channel press is completed in stages in grouping. In one activity cycle, the channel is first sifted, then, at that point, the channel cake is washed with water, subsequent to washing, the machine is halted and the slag is dumped, the plate, casing and channel media (channel fabric) are cleaned and afterward gathered for the following cycle; the ideal opportunity for dumping, cleaning and collecting is fixed, while the separating time and washing time are variable. The sifting time is neither too long nor excessively short. On the off chance that the filtration time is excessively long, albeit the normal filtration rate and washing rate is enormous, yet the dumping, cleaning, stacking and other assistant activity time in an activity cycle represented a bigger extent, actually make the creation limit is little. The creation limit is still little. Hence, the hour of each stage can’t be resolved discretionarily, that is, under specific working conditions, there is an ideal working cycle. Simply by working at the ideal working cycle would the creation limit be able to be amplified. At the end of the day, provided that the machine is worked at the ideal working cycle will the channel region needed to finish a specific filtration task be negligible and affordable.
The working tension of the channel press is the main impetus for filtration, and a higher working strain will bring about a higher filtration rate. Be that as it may, since the fine particles are not difficult to go through the separating medium toward the start of filtration, steady speed filtration is typically completed toward the start of filtration, for example at a more modest filtration rate, and afterward consistent tension filtration is completed after the arrangement of a specific thickness of channel cake.
2 Calculation equation induction process
The essential condition for filtration is:
Picture
Where: V a volume of filtrate, m³
τ a filtration time, s
K a filtration consistent, ㎡/s
A filtration region, m²
Ve a virtual filtrate volume of the channel medium, m³
2.1 Filtration stage
The filtration stage is separated into two sections: consistent speed filtration and steady strain filtration. In steady speed filtration, the filtration speed is consistent and the volume of filtrate V’ is gotten as
The volume of filtrate got by steady speed filtration and the time required are
where: V’a volume of filtrate acquired by consistent speed filtration, m³
UR a consistent speed filtration rate, m³/m2/s
τ’ a consistent speed filtration time, s
For consistent tension filtration, the essential condition for filtration is coordinated:
Then, at that point, the ideal opportunity for steady strain filtration is
2.2 Washing stage
The washing stage is a steady strain activity, on the grounds that the plate and casing channel press embraces the cross over washing strategy, so the washing region is half of the separating region, and the washing opposition is! Assuming the washing pressure is equivalent to the consistent strain filtration pressure, and the thickness of the wash water is like that of the filtrate, the connection between china filter press machine the washing rate (wash) and the last filtration rate (end) is
The volume of wash water is corresponding to the volume of filtrate, for example Vw = aV, in this manner.
Where: Vw a wash water volume,m³
a proportion of wash water volume to filtrate volume, causeless
τ’w a washing time,s
Assuming the washing pressure is not the same as the steady strain filtration pressure or the thickness of the washing water is unique in relation to the consistency of the filtrate, the washing time should be revised by the accompanying equation:
where μw, μ I are the wash water thickness and filtrate consistency separately, N S/m2
ΔPw, ΔP I are the washing pressure and the consistent strain filtration pressure separately, Pa
S a compressibility list of the channel cake, no component
2.3 Production limit
The creation limit of a channel press is generally communicated as far as the volume of filtrate got per unit of time. In a working cycle, the time outside the filtration stage isn’t separated, yet is as yet considered piece of the creation time. This implies that the limit is determined based on the complete time spent in a working cycle.
The limit of a channel press can be determined utilizing the accompanying recipe.
Where: τD a slag dumping, cleaning, stacking and other helper activity time, s
Q – the creation limit of the channel press, m³/s
Bring (3) and (4) into the above recipe separately, and make
Subbing (8) into condition (7), the most extreme creation limit is acquired as
2.4 Effect of working strain on filtration
The filtration steady K fluctuates with the working tension of the channel press as follows.
where k is a steady describing the properties of the channel material, m4/N.s
The opposition of the channel media can be determined utilizing the accompanying equation.
Where, Re an obstruction of the channel medium, 1/m
γ0 a particular obstruction of the channel cake per unit pressure contrast, 1/㎡
υ a proportion of the volume of the channel cake to the comparing volume of the filtrate, without factor
3 Examples of separating region and working conditions
In the creation of a suspension, the channel is needed to accomplish a creation limit of 21 m³/h, the filtration speed in the consistent speed stage is UR = 9.5 x OK m³/㎡/s, the proportion of wash water volume to filtrate volume is eight percent, the working strain during washing is equivalent to the working tension during steady strain filtration, the wash water thickness is 1.04 mPa/s and the filtrate thickness is 2.31 mPa/s. The suspension is sifted at The suspension was tried with a little channel press at a working strain of 300 kPa and the filtration consistent K’=1.5 x OK m²/s was estimated, the virtual filtrate volume per unit region qe’=0.029 m³/m2 and the compressibility list of the channel cake S=0.3. The channel press ought to be chosen for the channel region and the not set in stone.
The working tension of a conventional channel press for the most part doesn’t surpass 800kPa, so accept briefly that the working strain is that worth.
As indicated by the two conditions (10) and (11), since k, s, Re, γ0, υ and A don’t change with the working strain, it follows that
The volume and season of the filtrate in the steady speed stage are gotten from conditions (1) and (2), separately.
The greatest creation limit can be found by condition (9) as
At the point when the greatest limit is the accomplished 5.83 x 10-3m³/s, the channel press has a channel area of 28.2 m². As per the series of models for channel presses, the nearest separating area of 30 m² is chosen. This computation additionally decides the working states of the channel press.
Expecting a working strain of 672 kPa for the channel press, following the above calculation, this gives
Thusly, the channel press can play out its creation assignments at a working strain of 672kPa.
The volume of filtrate got in one working cycle is given by condition (8) as
The consistent strain filtration time and washing time are gotten from conditions (3) and (4), individually: Picture
The absolute time needed for one working cycle is given by
4 Discussion of the outcomes
From the above estimation, we can pick a plate and edge channel press with a filtration area of 30 m² and take on a working tension of 672 kPa and the best working cycle, for example steady speed filtration for 122 s and afterward consistent tension filtration for 987 s, trailed by washing for 292 s lastly dumping, cleaning and reloading for 20 min, to accomplish a creation limit of 21 m³/h.
At the end of the day, while sifting a specific suspension, the limit of the channel press changes with the working strain and working cycle. At a specific working tension, the limit of the channel press is amplified when it is worked at the ideal working cycle. At the point when the greatest limit is equivalent to the necessary limit, the comparing filtration region is the base filtration region needed at the most extreme working strain, for example the most practical and sensible filtration region, and afterward the material channel press is chosen by the series of rules for channel presses.
When the channel press has been chosen, the ideal working strain and working cycle should not entirely settled. The above estimation strategy isn’t simply used to decide the separating region of the channel press and to choose a reasonable channel press, yet additionally to further develop the creation limit of the channel presses being utilized underway.