Overview
Seal replacement for Spitzer silo trailers — hatches DN500/DN450, discharge valves, transfer pipe flanges DN80–DN150, hoses, pressure gauges — with material selection matched to the transported product: EPDM (granulates, cement, lime), FDA silicone (food-grade), Viton/FPM (chemicals, oils), PTFE (chemical and temperature extremes). Every seal supplied with a material certificate; food-grade applications certified to FDA standards. PHS Magnum stocks popular sizes for immediate dispatch from Chorula near Opole; special hatches available to order. Pressure test at operating pressure performed after every replacement.
Seals on a Spitzer Silo Trailer — the Critical Sealing Point
Seals are the most frequently replaced components on Spitzer silo trailers. They are the critical factor for overall system integrity — material leakage, product contamination, inability to hold working pressure — everything depends on seal condition.
PHS Magnum supplies a complete range of Spitzer seals: hatches, discharge valves, transfer pipe flanges, and transfer hoses. All components are supplied with full material certification.
Seal Materials — Selection by Application
EPDM (Ethylene Propylene Diene Monomer)
The most popular choice — a versatile material for the majority of industrial applications.
- Temperature range: −40°C to +120°C
- Resistant to: ozone, UV, water, mild acids and alkalis
- Not resistant to: oils, fuels, organic solvents
Applications: PE/PP/PVC granulates, cement, hydrated lime, talc, bentonite, recyclate materials.
FDA Silicone (food-grade)
For food products — certified for direct food contact.
- Temperature range: −60°C to +230°C
- Certification: FDA 21 CFR 177.2600, EU Regulation (EC) 1935/2004
- Excellent resistance to steam sterilisation and repeated cleaning cycles
- Note: lower mechanical strength than EPDM — requires careful torque application
Applications: flour, starch, sugar, dried dairy products, food additives, food-grade granulates (R-PET food-grade).
Viton / FPM (Fluoroelastomer)
For chemicals and oils — highest chemical resistance.
- Temperature range: −20°C to +200°C (short-term peak)
- Resistant to: oils, fuels, most industrial chemicals, hydrocarbons
- Note: higher cost (3–5× EPDM)
Applications: industrial chemicals, process oils, fuel dusts, non-standard bulk materials.
PTFE / Teflon
Maximum chemical and temperature resistance.
- Temperature range: −200°C to +260°C
- Resistant to: virtually all chemicals, strong acids and alkalis
- Note: highest cost; lower elasticity makes fitting more demanding
Applications: chemical extremes (strong acids and alkalis), high-temperature bulk materials, super-clean food-grade applications.
Where Seals Are Used — Spitzer Silo Trailer
Hatches
Main loading and inspection hatches — circular seals DN500 (most common) or DN450. Subject to the greatest number of mechanical cycles (opening/closing) — highest replacement frequency. For full selection, see filling hatch gaskets and rear hatch (domdeckel) seals.
Discharge Valves (butterfly valves)
Internal sealing of butterfly valves — disc and flange gaskets. Critical for integrity during pressurised discharge. Full service and spares: discharge valve service.
Transfer Pipe Flanges
Pipe connections DN80–DN150 — flange gaskets. The most common source of minor leaks on older trailers.
Transfer Hoses
Hose end fittings at loading/discharge points — Camlock seals and adapters.
Pressure Gauges and Ancillary Equipment
Small seals on pressure gauges, safety valves, and sensors — frequently overlooked during routine maintenance.
Hatch Seal Replacement Procedure
- Remove the existing seal (lift hatch cover, extract seal from its seat)
- Clean the seal seat (remove all residue from old material, visual inspection of the seating surface)
- Lubricate the seat surface (food-grade lubricant for FDA silicone seals)
- Fit the new seal into the seat with correct orientation
- Refit the hatch cover with correct torque (in accordance with Spitzer specifications)
- Pressure test at operating pressure
- Log entry in the service record (date, material, seal batch number, certificate reference)
Time: 30–60 minutes per hatch for an experienced technician.
Symptom, Cause, Action
Diagnosing a leak starts with locating the source — different points have different typical causes:
| Symptom | Probable Cause | Action |
|---|---|---|
| Dust leaking around hatch despite tightening | Hardened or cracked hatch seal | Replace DN500/DN450 seal |
| Loss of working pressure during discharge | Leaking discharge valve (disc seal) | Replace butterfly valve seals |
| Minor leak at pipe joint | Worn flange gasket | Replace flange gasket DN80–DN150 |
| Accelerated seal wear | Wrong material for the medium | Select elastomer matched to the product |
| Food-grade product contamination | No FDA certificate / material degradation | Replace with FDA-certified silicone or PTFE |
PHS Magnum Stock
| Category | Material | Availability |
|---|---|---|
| Hatch seals DN500 | EPDM | In stock (10+ units) |
| Hatch seals DN500 | FDA Silicone | In stock (5+ units) |
| Hatch seals DN500 | Viton/PTFE | 24–48 h |
| Hatch seals DN450 (older models) | EPDM | 24–48 h |
| Flange gaskets DN80–150 | EPDM | In stock |
| Flange gaskets DN80–150 | FDA Silicone | 24–48 h |
| Camlock seals | All materials | In stock |
Contact
Seal replacement and material selection for Spitzer trailers (hatches, valves, flanges, hoses). When enquiring, please provide the model (SF or SK series), year of manufacture, and the material being transported — we will select the correct seal with the appropriate certification. Ask for a quote and lead time.
Related: Spitzer Service — periodic inspections · Spitzer discharge valve service · Filling hatch gaskets · Top hatch bolts (wing-nut assemblies) · Rear hatch seals · TDT Inspection Spitzer · Spitzer not discharging — diagnostics · Spitzer trailer repair

