When I review a hot-fill gel line, I start with the closure route rather than the filler name. In this project, several container formats share the heated filling and cooling section, then branch into different capping or sealing operations. That branch is the engineering feature that determines the change parts, operator work and downstream interfaces.
The line is arranged around a 180 g air-freshener gel fill, a ten-head heated filler and an approximately 9 m cooling tunnel with three 10 hp cooling units. I treat the stated 4,000 bottles per hour as a design reference for that fill condition, then set the final recipe with the actual gel and container.
| Pack route | What happens after cooling | What I set up first |
|---|---|---|
| Automatic cap | Bowl-fed cap is placed and pressed | Cap orientation, bottle support and press height |
| Manual-cap format | Operator places the cap and a cylinder presses it | Operator position, bottle pitch and cap alignment |
| Roll film | Roll film is sealed at a dedicated station | Film width, mouth geometry, heat and dwell |
| Buyer-supplied induction seal | Cap is placed and pressed before the buyer’s sealer | Conveyor hand-off, sealer position and ownership boundary |
Some formats use dedicated fixtures and some do not. I therefore set the conveyor guides from the smallest stable bottle reference first, then check the larger format for clearance at the tunnel turns and at the first closure station. The outer size of the largest bottle alone is not enough to define the guide arrangement.
The shared section includes a mixing tank, heated product supply, a ten-head filler and touchscreen temperature control. Product-contact parts are stainless steel 316 and the machine frame is stainless steel 304. The tank, pump, hopper level and nozzle need to be reviewed as one thermal path; heating only the filler can leave a cold spot upstream.
For the heated product, I set the mixing temperature, replenishment level and filling temperature together. The gel’s setting behavior, foaming and permitted hold time decide whether the pump and pipe need additional heat retention. The operator should be able to see a low-level condition before the filling head draws air or the line moves into a different closure route.
| Thermal point | Practical observation | Why it matters downstream |
|---|---|---|
| Mixing tank | Temperature, agitation and working level | A stable feed gives the filler a repeatable product condition |
| Hopper | Level recovery after a fill cycle | Low level can cause air, drips or a change in fill appearance |
| Nozzle | Rim wetting, stringing and restart behavior | A clean mouth is needed for cap or film sealing |
| Tunnel exit | Gel surface and bottle spacing | The next station must receive a stable, correctly located bottle |
The tunnel is approximately 9 m long, with conveyor speed adjustable from 3 to 15 m/min and three 10 hp cooling units. Those values give me a useful starting window. During the product run, I look at the gel at tunnel entry and exit, bottle spacing through the turns and the mouth condition when the container reaches its cap or seal station.
A short stop deserves its own check. Gel left in a nozzle, pipe or bottle can change state while the conveyor is stationary, so the first container after a restart is more informative than a smooth middle run.
The induction sealer in this layout is supplied by the buyer. I define its conveyor height, signal exchange, bottle orientation and emergency-stop connection before calling the upstream line ready. The filler and tunnel can run correctly while the downstream sealer still lacks a usable hand-off.
For each format, I keep four items in the setup sheet: the cap or film supplied, the station that performs the closure, the physical change parts and the restart action after a stop. This makes a format change a real operating procedure instead of a new value typed into the touchscreen.
The project is a good example of why hot filling, cooling and closure should be designed as one format matrix. The 9 m tunnel and ten-head filler are shared anchors; cap, film, fixtures and the downstream owner change with the pack.
For the thermal section, see GDHP’s hot filling and cooling tunnel solution. The closure branches connect to the capping machine range, and the selection logic is covered in the hot filling machine buying guide.
