How to use Horizontal Vacuum Belt Filter and Liquid Ring Vacuum Pump Sizing Calculator
- Enter Wet Slurry Feed Rate (t/h) and adjust the options as needed.
- Run the tool and inspect its results, evidence and limitations.
- Copy or download the result, then verify it against the actual website, source data or business records.
Try a concrete example
In a hydrometallurgical leaching residue or FGD gypsum dewatering project, wet slurry feed rate is 25.0 t/h at 28.0 wt% solids concentration, targeting cake residual moisture <= 10.0%. A horizontal vacuum belt filter with 18.0 m² active filtration area is selected operating at -55.0 kPa vacuum box pressure, with a specific vacuum air factor of 3.5 CFM/ft²: Based on solid-liquid mass balance, dry solids output is exactly 7.00 t/h; wet cake discharge is 7.78 t/h (containing 0.78 t/h residual moisture); mother liquor filtrate flow is 17.22 m³/h; specific dry solids filtration capacity is 388.89 kg/(m²·h); total vacuum air requirement is 678.13 CFM (19.20 m³/min); liquid ring vacuum pump isothermal compression shaft power is 33.85 kW; with a 1.25 service factor and starting margin, a 45 kW (or 40 kW compact) industrial vacuum pump skid is recommended. Cake discharge is smooth and dewatering performance is exceptionally stable.
How to interpret results
The horizontal vacuum belt filter is the core continuous solid-liquid separation and washing machine in phosphoric acid, hydrometallurgy, fine chemicals, TiO2, and flue-gas desulfurization (FGD) gypsum dewatering plants. Operating with a continuous heavy-duty rubber carrier belt and synthetic filter cloth over stationary low-friction vacuum suction boxes, slurry is rapidly filtered into a cake under combined gravity and vacuum differential pressure. The cake advances through filtration, multi-stage counter-current washing, and final vacuum drying zones. The liquid ring vacuum pump provides the vacuum driving force; its volumetric air capacity (CFM or m³/min) must precisely match cake capillary air permeability while allowing for vacuum box sealing air ingress. Modeling solid-liquid mass balance, specific area throughput, vacuum air capacity, and shaft power ensures low cake moisture, seamless cake discharge, and reliable vacuum pump operation.
Frequently asked questions
Why must the specific vacuum air factor (CFM/ft²) be tailored to cake microstructure?
Vacuum sizing depends on cake air permeability: First, coarse, fast-filtering cakes (e.g., phosphogypsum, mineral sands, coarse crystals): high porosity yields low flow resistance and rapid air throughput, requiring 4.0–8.0 CFM/ft² vacuum capacity to sustain operating vacuum. Second, fine cohesive cakes (e.g., fine alumina, TiO2 hydrate): tight particle packing creates high capillary resistance, calling for 1.5–3.0 CFM/ft² with high vacuum level (-60 to -75 kPa) rather than excessive airflow. Third, misjudging the air factor causes either severe vacuum loss or wasteful pump oversizing.
What are the friction reduction and water seal requirements for vacuum belt slide tables?
Sliding friction between the rubber carrier belt and vacuum box is critical: First, wear strips and UHMW-PE slides: the vacuum box top is fitted with UHMW-PE slide plates upon which vulcanized sacrificial wear strips on the belt slide under high differential vacuum. Second, water lubrication and dynamic sealing: clean seal water must continuously inject into slide grooves at slight positive pressure, cutting friction by >60% while forming an airtight water barrier against atmospheric leakage. Third, dry running without lubrication will destroy the plastic slides and scorch the rubber belt within minutes from frictional heat.
How does multi-stage counter-current washing enhance mother liquor recovery on belt filters?
For valuable mother liquors or high-purity cake requirements (e.g., phosphoric acid extraction): First, counter-current concentration gradient: 2 to 3 discrete wash zones are arranged along the belt. Fresh wash water sprays onto the final zone; resulting weak filtrate is collected and pumped backward to spray onto the preceding zone; richest wash filtrate combines with primary mother liquor. Second, water efficiency and recovery: this arrangement uses ~1/3 the fresh water of co-current washing while boosting solute recovery above 99.2% and reducing thermal evaporation load downstream.
How do you prevent seal water temperature rise and cavitation in liquid ring vacuum pumps?
Gas compression heat in liquid ring pumps is absorbed entirely by the circulating seal water: First, vapor pressure and cavitation limits: if seal water exceeds 35°C–40°C, its vapor pressure approaches the suction vacuum level (-80 kPa), causing flash vaporization in the impeller suction zone. Bubbles collapse violently in discharge zones, producing severe cavitation pitting and impeller blade failure. Second, dedicated heat exchanger loop: hot seal water must circulate through an air-water separator and a closed plate heat exchanger, keeping supply seal water <= 25°C to preserve pump capacity and cavitation safety.