Selection of the head pressure for filter pump
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Neutral leaching filter pump: Used for a 100 square meter filter press (with a vertical height difference of about 8 meters). The feed pressure for the filter press is ≤0.8 MPa, and the pressing pressure is ≤1.2 MPa. The feed flange has a diameter of DN80. What is an appropriate head value for this filter pump? Previously, the designers in our company chose a head of 50 meters. One pump manufacturer stated that this value was too high, as it would cause the pump to break easily, while another pump manufacturer considered it appropriate. The filter press manufacturer also said that at least 50 meters was necessary. I don’t have any relevant experience. Could anyone who knows about this offer some advice?
The feed pressure for a filter press is usually around 5-6 kilograms; it’s advisable to choose a pump with a head of 50-60 meters. A pump driven by an engine with a low rotation speed will last much longer (avoid pumps with 2900 revolutions per minute, as higher speeds lead to faster wear). It’s also best to use a pump with a mechanical seal and cooling water for flushing, and a (semi)open impeller slurry pump. Our company has many successful cases.
The filter press manufacturers also say it needs at least 50 meters, and they are right. There is also a vertical height difference of about 8 meters.
I’m currently using a motor of grade 4; the manufacturer of that pump used a motor of grade 2 yesterday, which is why they raised the issue regarding the high head pressure. So it can be understood that it’s because they use motors of level 2 with too high a speed, which causes the pump to wear out quickly, right?
It is correct to use a low-speed four-stage motor; the pump manufacturer might have chosen a two-stage motor in order to reduce costs (four-stage motors are more expensive), but two-stage motors for filter presses are very unsuitable for long-term use.
As the feed pump for filter presses, apart from centrifugal pumps, other types of pumps are also available; head is not an issue – what matters most is the pump’s performance and reliability. The German EMMERICH electric piston diaphragm pump is designed specifically for applications with high pressures.
The problem I’m facing is that the senior engineer insists on using a pump with a head of 30 meters; compared to a pump with a head of 50 meters, what is the difference in efficiency? Please give me some guidance, master
A head of 60 meters is more appropriate; given the height difference and feed pressure, the head at the low-flow end of the pump’s performance curve should be considerably higher in order to function properly, otherwise the required pressing pressure cannot be achieved. The curve of the filter press pump should be steep enough to accommodate the constantly changing flow rate and head required by the filter press.