A positive-pressure inline Siever is sealed and pressure-rated (up to 6 bar) for installation within positive-pressure pneumatic conveying lines dense-phase or dilute-phase where powder is pushed by compressed air rather than drawn by vacuum. Processing 100–15,000 kg/h with screen apertures of 0.5–10 mm at operating pressures of 0.2–4 bar, it provides inline oversize rejection and de-lumping for high-throughput positive-pressure transfer systems used in food, chemical, and bulk pharmaceutical manufacturing where vacuum conveying is not practical due to transfer distances, product density, or system capacity requirements.
Powder-laden compressed air enters the pressure-rated Siever body through the feed inlet; the screen (0.5–10 mm aperture) allows on-specification particles to pass through and continue in the downstream pipeline while oversize particles are retained on the upstream face. A timed purge valve periodically diverts airflow to blow accumulated oversize into the reject chamber the oversize is then discharged through a pressure-rated reject valve to a reject collection vessel. Body pressure rating (1–6 bar design pressure) is selected to match the pneumatic conveying system operating pressure with 3:1 safety factor. All seals are pressure-rated EPDM or PTFE; the body is hydrotested before commissioning.
Challenges
High-Velocity Particle Impact on Screen at Positive Pressure (Dense-Phase Slug)
Dense-phase slug hitting screen at 2–10 m/s causes rapid screen aperture deformation and wear.
Oversize Reject Discharge Against Positive System Pressure
Reject valve must open against 0.2–4 bar system pressure pneumatic actuator force sized accordingly.
Pressure Surge at Blow Tank Cycle Start Overloading Screen
Dense-phase blow tank cycle creates pressure surge at each start screen must withstand dynamic impact load.
Seal Integrity at High Continuous Operating Pressure
All body seals and screen frame seals must maintain integrity at rated pressure continuously.
Screen Change Under Pressurised System Requires Full Pressure Isolation
Positive-pressure system must be fully depressurised before screen access creates line downtime.
Solutions
- Heavy-Duty Punched Plate Screen (SS 316L, 3 mm Plate, HRC 40 Hard-Faced): Rigid hardened plate withstands dense-phase slug impact without aperture deformation.
- Oversized Reject Valve Actuator (Force Margin 3× System Pressure): Actuator sized for 3× operating pressure opens reject valve reliably against maximum system pressure.
- Shock-Absorbing Screen Mounting Frame (Rubber-Backed Screen Seat): Rubber-backed frame absorbs blow tank cycle impact prevents transmission to screen mesh welds.
- Double O-Ring Body Seals (Dual Redundancy at All Pressure Faces): Dual O-ring grooves provide redundant sealing single O-ring failure does not cause body breach.
- Isolation Valve + Pressure Relief at Siever Body (30-Second Depressurisation): Dedicated isolation valve and relief port depressurise Siever body in 30 seconds minimal downtime.
Applications
- Food & Beverage: High-throughput flour, starch, and sugar inline sieving in dense-phase positive-pressure transfer systems.
- Chemical: Fertiliser granule, polymer pellet, and mineral inline oversize rejection in positive-pressure pneumatic lines.
- Pharmaceutical: Bulk excipient and API granule de-lumping in positive-pressure transfer where distance exceeds vacuum range.
- Feed & Agriculture: Animal feed ingredient inline de-lumping in high-capacity positive-pressure pneumatic conveying systems.
- Dairy: Milk powder, whey, and infant formula inline sieving in dense-phase positive-pressure transfer systems.
Models & Capacities
| Type 5 Positive-Pressure Inline Siever (Dense-Phase Compatible): Models & Capacities | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Model | Scale | Transfer Rate [kg/h] | Body Ø [mm] | Screen Aperture [mm] | Design Pressure [bar] | Op. Pressure [bar] | Inlet/Outlet Ø [mm] | Reject Valve Actuator | Body L × Ø [mm] | Weight [kg] |
| IVS-PP-LAB | Lab/Pilot | 100–500 | Ø100 | 0.5–5 | 6 bars | 0.2–2 | Ø50 | Pneumatic | 280×Ø140 | 22 |
| IVS-PP-PIL | Pilot | 300–1,500 | Ø150 | 0.5–8 | 6 bars | 0.2–3 | Ø65 | Pneumatic | 380×Ø195 | 42 |
| IVS-PP-1000 | Production | 500–3,000 | Ø200 | 0.5–8 | 6 bars | 0.2–4 | Ø80 | Pneumatic | 500×Ø255 | 75 |
| IVS-PP-2000 | Production | 1,000–5,000 | Ø250 | 0.5–10 | 6 bars | 0.2–4 | Ø100 | Pneumatic | 620×Ø310 | 115 |
| IVS-PP-4000 | Production | 2,000–8,000 | Ø320 | 1–10 | 6 bars | 0.2–4 | Ø125 | Pneumatic | 780×Ø385 | 175 |
| IVS-PP-6000 | Production | 3,000–12,000 | Ø400 | 1–10 | 6 bars | 0.3–4 | Ø150 | Pneumatic | 950×Ø470 | 270 |
| IVS-PP-10000 | Large Prod | 5,000–20,000 | Ø500 | 1–10 | 6 bars | 0.3–4 | Ø200 | Pneumatic | 1,200×Ø580 | 420 |
| IVS-PP-15000 | Large Prod | 8,000–30,000 | Ø630 | 2–10 | 6 bars | 0.3–4 | Ø250 | Pneumatic | 1,500×Ø720 | 650 |