Whether grain is to be conveyed pneumatically from the intake point into the store, a silo aerated or a dryer connected – the pipework plays a large part in how reliably and energy-efficiently the whole plant works. A well-planned conveying line keeps the runs short, avoids unnecessary changes of direction and can later be extended or reconfigured without great effort.
Kongskilde offers two modular pipe ranges for this: the OK pipe system and the FK pipe system. Both consist of matched pipes, bends, branches and couplings, but differ in their main field of use, diameter range and joining technique. This guide shows which system is intended for what – and what matters in diameter choice, bends and assembly.
Which system for what? OK and FK at a glance
OK pipe system: pneumatic and mechanical conveying
The OK pipe system is designed for pneumatic and mechanical conveying, making it the first choice when grain is moved with blower air or by mechanical conveyors. The pipes are made of galvanised sheet steel and are available in three nominal diameters: OK 100 (100 mm), OK 160 (160 mm) and OK 200 (200 mm). The rolled pipe ends stiffen the pipe and, together with the quick couplings, ensure tight joints. Typical locations are grain bins, silos and awkward buildings in which the line has to be routed around obstacles.
FK pipe system: aeration and pneumatic conveying
The FK pipe system is tailored to aeration and pneumatic conveying applications. According to the manufacturer, its modular range covers diameters from 60 to 800 mm; the current type overview lists sizes from FK 80 up to FK 1250, with the largest nominal diameters also supplied with a bolted flange. The system is deliberately kept simple and flexible: pipes, bends, branches and diverter valves are joined with quick-release or bolt clamps and therefore integrate well into existing buildings and plants.
The key differences at a glance:
| Criterion | OK pipe system | FK pipe system |
|---|---|---|
| Main field of use | Pneumatic and mechanical conveying | Aeration and pneumatic conveying |
| Diameters | 100, 160 and 200 mm (OK 100/160/200) | Types FK 80 to FK 1250 (largest sizes with bolt flange) |
| Material and design | Galvanised sheet steel, rolled pipe ends | Modular design in high-grade materials |
| Joining technique | Quick couplings | Quick-release or bolt clamps, large nominal diameters with bolted flange |
| Bends | R = 1.5 × D and R = 3 × D, plus the OKX 160 in hardened steel | R = 1.5 × D and R = 3 × D |
| Typical installation | Grain bins, silos, awkward building layouts | Integration and retrofitting into existing structures, aeration runs |
Choosing the right diameter
In the OK system the choice is deliberately compact: three nominal diameters covering the spectrum of classic on-farm conveying. The diameter is governed first and foremost by the blower or conveying unit the line will be run with, and by the required capacity. A continuous nominal diameter from the machine connection to the outlet makes sense; where different connection sizes meet, transition pieces from the accessory range join the components.
The FK range is graduated much more finely. At the lower end there are FK 80, FK 100, FK 120, FK 125, FK 140, FK 150, FK 160, FK 180 and FK 200, followed by FK 225 to FK 500 and finally the large pipes FK 550 to FK 1250. The line can thus be sized closely to the air requirement of each application – from the compact conveying run to the large aeration duct. For aeration duties the overview also lists perforated pipes (FB 450, FB 500 and FB 600) as well as pipes with grille.
If you are unsure which nominal diameter suits your blower and conveying run, the spare parts finder helps with the pre-selection – or take your cue from the connection size of the existing machine.
Planning bends, limiting wear
Every change of direction increases the resistance in the line. Both pipe ranges are therefore expressly designed to shorten transport routes and keep the energy demand low. For planning this means: as few bends as possible, and better to think the route through properly once than to correct it later.
Both systems offer bends in two radii: the standard radius R = 1.5 × D and the large radius R = 3 × D. The larger radius turns the conveyed material more gently and suggests itself wherever there is enough space. For heavily stressed points, the OK range additionally provides the OKX 160, a bend in hardened steel designed for high wear resistance and a long service life. If you regularly convey large volumes, plan such wear-resistant bends in from the start – thanks to the coupling technique, swapping individual bends later remains simple anyway.
Assembly in practice: couplings, clamps and accessories
Assembly is where the modular idea of both systems shows. OK pipes are joined with quick couplings; that speeds up installation and allows the plant to be reconfigured later without great effort. The FK system uses quick-release or bolt clamps, with bolted flanges and weld-on adapters for fixed joints at the largest nominal diameters.
Both ranges come with an extensive accessory programme that eases the actual planning work:
- Telescopic pipes take up differences in length along the run.
- Transitions and branch pipes connect nominal diameters and split the material flow.
- Two-way diverter valves direct the material into one of two directions, for instance onto two storage cells.
- Shut-off slides and regulating dampers control material flow and air volume.
- Pipe clamps and pipe brackets secure the line along the run.
- Silencers lower the noise level of the air routing.
- Rain caps and non-return flaps protect line ends outdoors.
- Flexible hoses and adapters make the connection to machines and on-site structures.
All components of both systems are gathered in the category Conveying Pipes.
Working together with blower, cyclone and aeration
A pneumatic conveying line is always part of a complete system: the blower generates the airstream, the pipework carries the grain, and at the end of the run a cyclone, for example, separates conveyed material and conveying air from each other again. For this interplay to work, the nominal diameter of the pipes and the connection size of the machine must match; transitions, flexible adapters and weld-on adapters from the accessory range make the connection. Regulating dampers serve as air regulation to match the airstream to the application, and silencers reduce the operating noise.
Matching blowers and complete conveying units can be found in the category Pneumatic Conveyors. For aerating stores and silos, in turn, the FK range with its large nominal diameters and perforated pipes forms the basis – from the fan connection to the air distribution in the store.
Recommended action: six steps to your conveying line
- Clarify the task: conveying (pneumatic or mechanical) or aeration? That sets the pre-selection – OK for conveying duties, FK for aeration and pneumatic applications with a broad diameter requirement.
- Sketch the route: fix the shortest sensible path from feed point to discharge point and mark the necessary changes of direction.
- Set the diameter: to match the blower or conveying unit and the required capacity; plan transitions only where they are unavoidable.
- Choose bends deliberately: as few as possible; for heavy duty, provide wear-resistant versions such as the OKX 160, and where space allows, the large radius R = 3 × D.
- Add accessories: brackets, diverter valves, regulating dampers and rain caps – depending on the installation, telescopic pipes and flexible connections too.
- Keep expansion open: thanks to the modular coupling technique, both systems can be extended or rebuilt later. Plan branches where further take-off points are conceivable in future.
Planned this way, the conveying line grows with the farm: today a simple run from the intake point into the store, tomorrow a branched network with several take-off points – with OK and FK it remains the same modular system.
Frequently asked questions
What is the difference between the Kongskilde OK and FK pipe systems?
Which diameters are available in the Kongskilde pipe systems?
How are the pipes of the two systems assembled?
What helps against wear in pipe bends?
Matching products
Related guides
- Designing flat store aeration: ducts, air volumes, grain depths
- Emptying silos and flat stores completely: vacuum clean-out in practice
- Finding Kongskilde Spare Parts: How to Use the Exploded Drawing and Part Number
- Grain Cleaning: Why Pre-cleaning Pays Off
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