Introduction
At the product outlet of Feldbinder silo trailers — whether the horizontal non-tipping EUT or the tipping pressure silo KIP (Kippsilo) — the ball valve alone is not always sufficient to ensure a clean, steady material flow. Bulk materials with poor flowability can bridge just downstream of the ball. That is why a blower is paired with the ball valve: it introduces compressed air directly into the outlet zone, breaks up any bridging, and assists the material on its way out.
On Feldbinder silo trailers the blower is one half of a matched pair: ball valve + blower form the complete outlet assembly. On EUT trailers each discharge spout ends with such an assembly, so multi-compartment versions have as many blowers as they have outlets. On KIP trailers — where the tilting action and the pneumatic system work together to empty materials with poor flowability — the blower at the outlet is especially important for achieving a full, clean discharge. We supply blowers matched to two valve types, Prokosch and ZR, in DN80 and DN100.
PHS Magnum in Chorula near Opole holds stock of blowers and of factory-assembled valve + blower sets. The full parts catalogue is available at /en/spare-parts/, and service information at magnumchorula.pl/en/service/.
Materials and Construction
The blower is a discharge-assist component, specified to match a particular valve (Prokosch or ZR) and its bore size.
| Component | Material |
|---|---|
| Body | Cast iron |
| Internal seal | Desmopan |
| Ring | Steel |
| External seal | NBR |
We supply blowers in DN80 or DN100 for both Prokosch and ZR valve types, as well as factory-assembled valve + blower sets.
The material selection reflects the operating environment. The cast-iron body provides the mechanical strength and robustness needed in the outlet zone, where the blower operates under pressure and in direct contact with bulk material. The Desmopan seal — a polyurethane elastomer with good abrasion resistance — seals the internal air-introduction channel and withstands continuous contact with flowing bulk material. The steel ring stabilises the assembly, and the NBR external seal seals the joint between the blower and the valve. This combination delivers reliable service life under normal silo trailer operating conditions.
Sizes and Types
| Bore DN (mm) | Compatible valve type |
|---|---|
| DN80 | Prokosch or ZR |
| DN100 | Prokosch or ZR |
The blower is selected to match the bore and type of the ball valve at the product outlet. For a complete outlet assembly replacement, factory-assembled valve + blower sets are available.
The key selection rule is that the blower must match both the bore (DN80 or DN100) and the valve type (Prokosch or ZR). A mismatch in either dimension results in leakage and ineffective discharge assistance. When ordering a blower alone, please specify the type and bore of the outlet valve. Where the entire assembly is being replaced, the factory-assembled valve + blower set is the simplest and most reliable option: the factory fit guarantees full compatibility and reduces installation time on the vehicle.
Compatibility with Feldbinder Silo Trailers (EUT/KIP)
On EUT trailers (horizontal non-tipping tank, pneumatic discharge via bottom spouts) the blower is fitted at the ball valve that closes each discharge spout. Multi-compartment EUT trailers have one valve + blower assembly per outlet, so the number of blowers matches the number of spouts. Correct matching of valve type (Prokosch or ZR) and bore (DN80/DN100) is essential.
On KIP (Kippsilo) trailers — tipping pressure silos where the tilting action assists the discharge of materials with poor flowability — the blower at the outlet works with the pneumatic system during the final phase of emptying, once most of the material has already moved. Blower selection follows the outlet valve size and type, not the trailer type, so the same DN80/DN100 range covers both EUT and KIP. Factory-assembled valve + blower sets simplify full assembly replacement in a single step.
Common Failure Modes on Feldbinder Silo Trailers
In day-to-day service of ball valve blowers on Feldbinder silo trailers, the most frequently encountered issues are:
- Desmopan seal failure — a worn internal seal reduces blower effectiveness and causes leakage; this is a replaceable component.
- NBR external seal deterioration — hardened or cracked external seal at the valve joint; replaced during outlet assembly service.
- Blower channel blockage — material deposit or dried product restricting airflow; cleared by cleaning, replaced if necessary.
- Cast-iron body corrosion — arising from moisture in the bulk material and condensate; body condition checked at service intervals. Where Feldbinder food-grade assemblies are involved, chemically resistant materials are specified where the design permits.
Blower seals are typically replaced at the same time as the ball valve service, since both components are matched and work in the same zone — which is why the complete valve + blower sets are often the most practical choice.
From a fleet maintenance perspective, it makes sense to treat the outlet valve and blower as a single service unit. Both components operate in the same zone, exposed to the same bulk material, pressure, and condensate. Servicing them together reduces downtime and keeps maintenance schedules straightforward. Checking the condition of the Desmopan and NBR seals should form part of the routine outlet assembly inspection whenever other work is being carried out on the ball valve. Catching a blower leak early avoids situations where a poorly flowing material bridges at the outlet and extends unloading time.
Availability and Delivery
- Stock at Chorula near Opole: DN80 and DN100 blowers for Prokosch and ZR, as well as complete valve + blower sets — standard items typically available ex-stock.
- 24–48 h: most standard lines.
- Direct delivery: non-standard configurations.
- Shipping: courier (Poland), GLS/DHL (DACH), EU VAT invoice.
All deliveries include a material certificate. Blower selection and valve + blower set assembly are handled as part of PHS Magnum service.
Related Categories
- Prokosch Ball Valves (Product Outlet)
- Segmented Ball Valves Type ZR
- Ball Seals
- PTFE Ball Valves
- Full catalogue: /en/spare-parts/
See also: This category in the PHS Magnum network catalogue (all makes) →
Author: Aleksy Pasternak — Managing Partner, PHS Magnum, 20 years in the industry, internal ISO 9001:2015 auditor (DEKRA).
