Endless liner systems: contained filling and emptying with liner technology

Endless liner technology is one of the most effective methods for contained filling and emptying of big bags with highly potent, toxic or valuable powders. The plastic liner forms a hermetic barrier between the product and the operator — without the complexity and cost of a full isolator system. This makes endless liner systems particularly popular in the pharmaceutical industry for OEB 3–5 applications.

What is an endless liner?

An endless liner is a continuous tube of polyethylene (PE) or other suitable plastic material, wound on a roll. The liner is pulled over the filling head or discharge head of the big bag and forms a closed, dust-free tunnel between the big bag and the production installation. After use, a section of liner is cut off and disposed of — so every transfer is covered with a clean, uncontaminated liner.

Endless liner filling heads: LBK, SBK and LBK-EC

LBK (Liner Bag Connector)

The standard endless liner filling head for big bag filling. The liner is pulled over the filling head and clamped in place. The powder flows through the liner into the big bag, fully shielded from the environment. After filling, the liner is pinched shut, cut off and knotted — the big bag is then contained and sealed.

SBK (Standard Bag Connector)

A more compact version of the LBK, suitable for smaller filling heads and limited space. Same operating principle as the LBK.

LBK-EC (Easy Connect)

Version with a Quick Connect mechanism for fast, contained coupling and decoupling. The operator does not need to manually pull the liner over the filling head — the connection clicks into place. Ideal for high throughput rates or frequent big bag changeovers.

Endless liner discharge systems: SAS

The SAS (Sleeve Attachment System) is the counterpart of the filling head: it is a contained connection point at the bottom of the big bag for discharging. The liner is connected to the process installation via the SAS connection, after which the material is transferred in a contained manner. After discharge, the liner is pinched shut and cut off — no product contact for the operator.

Containment levels with endless liner

Endless liner systems typically achieve an OEL (Occupational Exposure Limit) of 1–10 µg/m³, corresponding to OEB 4 performance. For OEB 5, additional measures are needed (e.g. combination with bag-in-bag transfer or an isolator). The advantages compared to an isolator: significantly lower investment costs, less validation effort and higher flexibility during product changeovers.

Materials and compatibility

Endless liners are available in:

LDPE (Low Density Polyethylene): standard, FDA-compatible, economical
HDPE: higher rigidity, suitable for abrasive materials
Antistatic PE: for explosion-sensitive materials (ATEX environments)
Aluminium laminate: for hygroscopic or light-sensitive products

Applications in the pharmaceutical industry

Endless liner systems are used in the pharmaceutical industry for:

Contained filling of big bags with API powder (OEB 3–4)
Contained emptying of raw material big bags into the production line
Intermediate transport of semi-finished products between production steps
Clinical batches where flexibility and fast product changeover are required

Hecht Technology: custom endless liner systems

Hecht Technology supplies the complete endless liner portfolio — from standard LBK filling heads to LBK-EC Easy Connect and SAS discharge systems. All systems are available in GMP-compliant versions with documented material certificates.

View our products: LBK-EC filling head, SBK filling head, SAS discharge system, endless liner material.

Conclusion

Endless liner technology offers a cost-effective solution for contained big bag handling at OEB 3–4 level. The combination of LBK/SBK filling heads, SAS discharge systems and the right liner specification delivers a robust, flexible and GMP-compliant system for the pharmaceutical and chemical industry.

Our endless liner products

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Author: Joost van Velzen, Managing Director Hecht Technology B.V.