SOSHH Snap-In Hopper Breather Bags for Dust Relief and Air Venting (FM1 Polyester Felt)
![SOSHH snap-in hopper breather bags with top loop handles and needle felt filter fabric for dust relief venting]()
Technical Image Caption: Heavy-duty needle felt breather bags featuring top suspension loop handles and quick-snap cuffs, engineered for positive pressure air venting and sub-micron dust containment on surge bins and weigh hoppers.
Engineered to Relieve Air Displacement Without Dust Leakage
When bulk dry solids drop from upstream rotary valves or screw conveyors into an enclosed vessel, incoming powder pushes an equal volume of air out. Traditional vented ducts with open cloth socks frequently leak airborne dust into cleanrooms or clog prematurely.
SOSHH snap-in breather bags solve this operational headache. The high-density needle felt matrix allows displaced air to escape freely across a large filtration surface area while preventing fine powders from blowing into your processing facility. The crevice-free internal snap cuff eliminates product accumulation traps, meeting strict cGMP hygiene requirements.
Key Engineering Advantages
Tool-Free 30-Second Snap-In Mounting
Internal stainless steel snap bands expand firmly into the spigot groove, forming a dust-tight mechanical seal without external hose clamps, tools, or silicone gaskets.
Sub-Micron Filtration Needle-Felt Membrane (FM1)
Calendered and heat-singed surface finish prevents loose fiber shedding into sensitive food ingredients while capturing sub-micron particulates with minimal blinding.
Integrated Top Loop Handle for Anti-Sagging Suspension
The reinforced top loop strap connects to an overhead hanger, keeping the breather bag vertical and fully extended even when process air pressure drops to zero.
Eliminates Parasitic Pressure in Weigh Hoppers
Vents positive air build-up instantaneously, preventing internal air pressure from exerting vertical forces on scale load cells and restoring gravimetric dosing accuracy.
Food Contact Compliance
Manufactured with virgin polyester fibers conforming to FDA 21 CFR 177.2600 and European food-contact migration standards.
Standard Size and Dimension Specifications
(Media: FM1 100% Polyester Needle Felt | Air Permeability: 120-160 L/dm2/min at 200 Pa | Max Continuous Temp: 130 C)
| Spigot Inner Dia (d) | Standard Diameter (OD) | Total Bag Height (L) | Top Closure Type | Filtration Efficiency |
|---|
| 100 mm | 100 mm (External) | 300 mm / 500 mm | Closed Top + Loop Handle | 99.5% at 1-3 micron |
| 150 mm | 152 mm (Internal) | 300 mm / 500 mm / 800 mm | Closed Top + Loop Handle | 99.5% at 1-3 micron |
| 200 mm | 204 mm (Internal) | 300 mm / 500 mm / 800 mm | Closed Top + Loop Handle | 99.5% at 1-3 micron |
| 250 mm | 254 mm (Internal) | 300 mm / 500 mm / 1000 mm | Closed Top + Loop Handle | 99.5% at 1-3 micron |
| 300 mm | 304 mm (Internal) | 500 mm / 800 mm / 1000 mm | Closed Top + Loop Handle | 99.5% at 1-3 micron |
| 350 mm | 354 mm (Internal) | 500 mm / 800 mm / 1000 mm | Closed Top + Loop Handle | 99.5% at 1-3 micron |
| 400 mm | 404 mm (Internal) | 500 mm / 800 mm / 1000 mm | Closed Top + Loop Handle | 99.5% at 1-3 micron |
(Note: Custom lengths up to 2000 mm, open-ended flow sleeves, and polypropylene LM3 sub-zero configurations down to -70 C are fabricated to order.)
Target Industrial Applications
- Weigh Hopper & Loss-in-Weight Feeder Venting: Eliminates air buffering to maintain scale tare precision during rapid refill cycles.
- Surge Bin & Buffer Hopper Pressure Relief: Equalizes positive pressure pulses generated by upstream pneumatic conveying discharges.
- Silo & Bin Exhaust Ports: Acts as localized passive filtration on small storage vessels without requiring motorized dust collector ductwork.
- Sifter & Screener Inspection Ports: Replaces solid viewing caps during continuous runs to release gyratory air turbulence.
Related Procurement RFQs and Technical FAQs
Q1: Why does a solid TPU connector cause scale drift on weigh hoppers, while a breather bag fixes it?
Mechanical Air Locking
When a solid polyurethane sleeve connects a feeding hopper to a weigh vessel, air displaced by incoming solids cannot escape. The resulting pressure pocket acts like an internal pneumatic spring, pushing down or lifting up the scale platform and generating weight measurement errors of 2% to 5%.
The SOSHH Breather Solution
The permeable FM1 felt wall provides a low-resistance path for displaced air to exhaust naturally while trapping every airborne particle inside the system. Scale tare stability is achieved instantly without erratic signal spikes.
Q2: How do I calculate the required breather bag surface area for my hopper?
Air Displacement Formula
Air Venting Volume equals Peak Powder Inflow Volume.
To ensure internal vessel pressure remains below 20 mbar during peak powder dump, maintain an air velocity through the filter medium below 0.05 m/s. For rapid dump hoppers (such as 1000 kg/min of flour or plastic pellets), choose a bag with at least 0.25 to 0.40 m2 of filter area (e.g., Dia 200mm x 500mm Length or larger).
Q3: What is the purpose of the top suspension loop handle?
Structural Stability
Unlike pressurized pneumatic systems that keep bags inflated, hopper venting applications experience fluctuating or negative air currents. The top loop allows operators to suspend the bag from an overhead hook or bracket. This stops the fabric from drooping, prevents self-choking creases, and ensures maximum active filtration surface at all times.
Q4: Can these needle felt breather bags be washed and reused?
CIP and Cleaning Guidelines
FM1 polyester felt can be cleaned by dry reverse-pulse dusting, vacuuming, or gentle water rinsing. Avoid harsh chlorine-based bleaching agents and continuous water temperatures above 70 C, which can weaken the internal mechanical snap-band bonding. Ensure the bag is completely dry before reinstalling to prevent powder bridging and blind caking.
Q5: Are anti-static versions available for explosive ATEX dust zones?
Static Dissipation Options
Yes. For combustible powders (e.g., starch, cocoa, sulfur, toner), SOSHH supplies needle felt integrated with stainless steel or conductive carbon fibers (10^6 to 10^8 Ohm surface resistivity), providing continuous electrostatic dissipation when installed in earthed steel spigots.
