Rear Hatch Seals

Introduction

On Spitzer SF and SK series silo trailers, the rear cover is the tank’s rear access hatch — a closable opening at the back of the silo through which cleaning, inspection, and internal servicing are carried out. Just as the upper fill hatch must be sealed tightly after loading, the rear hatch must remain leak-tight throughout the journey and during discharge. That seal is provided by a gasket seated between the rear cover plate and the hatch rim: it keeps the cargo inside the tank, blocks the ingress of moisture and contaminants, and allows working pressure to be maintained.

The rear hatch seal operates under conditions similar to those of the upper fill hatch seal — it is cyclically compressed and released, continuously exposed to the elements, dust, and contact with the cargo. Over time it hardens, cracks, or loses its resilience, causing the hatch to no longer close uniformly. Importantly, the Spitzer rear cover design incorporates two distinct sealing points: the silo side and the hatch itself. PHS Magnum maintains a stock of rear hatch seals at its facility in Chorula near Opole, covering the most widely used silo trailer brands, so the right component can be identified and dispatched without waiting for overseas supply.

Specification and Materials

We supply rear hatch seals matched to specific silo trailer brands. The range covers Spitzer (silo side and hatch), Feldbinder, and Kässbohrer (new and old type).

The key to a correct fit is matching the seal to a specific manufacturer’s cover. For Spitzer trailers, this means additionally distinguishing between the silo-side seal and the hatch seal. The same component across different brands — or even across generations of the same brand, as with Kässbohrer’s new and old type — may differ in profile and cross-section. For this reason we organise the range by brand and cover type rather than by universal dimensions.

The specific material and dimensions of each seal are determined by the brand and cover type of the trailer in question — the seat geometry and sealing profile are unique to each design and cannot be reduced to a single universal figure.

Sizes and Types

The rear hatch seal range is organised by silo trailer brand and cover type. Exact dimensional data is not stated for this category in the source documentation; selection is therefore carried out by brand and type rather than by DN value.

The common thread across the range is coverage of the most popular silo trailer brands in use on the DACH market and in Poland. For Spitzer, the offer is divided into the silo-side seal and the hatch seal — two distinct sealing positions on the rear cover. For Kässbohrer, the offer covers both the new and old cover type. When placing an order, please indicate which component and type your enquiry relates to.

Compatibility with Spitzer Silo Trailers (SF/SK)

The rear hatch seals in our range are assigned directly to the Spitzer, Feldbinder, and Kässbohrer brands — these are not unverified substitutes but components that correspond to the actual covers produced by these manufacturers. On Spitzer SF and SK series silo trailers, the rear tank hatch is sealed by two separate components: a silo-side seal and a hatch seal.

Because PHS Magnum services both Spitzer trailers and related Feldbinder and Kässbohrer designs, seal selection is conducted on the basis of the actual cover fitted, not solely the manufacturer’s name. When ordering, the essential information is the trailer brand and — for Spitzer — whether the silo-side seal or the hatch seal is required; and for Kässbohrer, whether the new or old type is needed.

Common Failure Modes

In day-to-day service practice, the rear hatch seal is a wear item replaced on a routine basis — it is stressed every time the hatch is opened and closed, and is permanently exposed to external conditions. Typical symptoms that indicate replacement is due include:

• Hardening and loss of resilience — the seal no longer returns to shape after compression, causing the rear hatch to close unevenly.
• Cracks and cuts — these break the continuity of the seal and lead to hatch leaks.
• Permanent deformation — a compressed, flattened cross-section no longer provides adequate contact pressure.
• Contamination and adhesion to cargo residue — impairs closure and accelerates wear.

In each of these cases the remedy is replacement with a seal matched to the brand and cover type. When replacing the seal, it is also worth inspecting the condition of the rear cover closing system — the seal and the locking hardware work together to maintain hatch integrity.

Availability and Delivery

Rear hatch seals for the most common silo trailer brands — Spitzer (silo side and hatch), Feldbinder, and Kässbohrer (new and old type) — are held in stock at our facility in Chorula near Opole. Despatch is by courier throughout Poland and to DACH countries (Germany, Austria, Switzerland).

To select the correct seal, please provide the trailer brand and indicate the relevant component of the rear cover (for Spitzer: silo side or hatch; for Kässbohrer: new or old type). For details and an individual quotation, ask for a quote.

Related Categories

• Rear Cover Bolts — the universal closing system for the Spitzer-Feldbinder rear cover, working in conjunction with the hatch seal.
• Fill Hatch Seals — seals for the upper loading hatches of Spitzer, Feldbinder, Omeps, and Kässbohrer silo trailers.
• Flange Seals — flange seals for Spitzer, Feldbinder, AKO, and Prokosch systems.
• Spitzer SF and SK Parts — overview of wear and structural parts for the SF and SK series.
• All Spare Parts — full parts catalogue for silo trailers stocked by PHS Magnum.
• Silo Trailer Service — PHS Magnum — refurbishment, repairs, and specialist silo trailer servicing.
• pasternak.me — expert portal covering trailer service, transloading, and bulk material transport.

See also: This category in the full PHS Magnum network catalogue (all brands) →

Author: Aleksy Pasternak — Managing Partner PHS Magnum, 20 years in the industry, internal ISO 9001:2015 auditor (DEKRA).