Drain hoses can be an afterthought in industrial design, which is easy to understand considering that their very purpose is to move discarded materials. On the other hand, those tubes are carrying material that needs to get from point A to point B for a reason, and failure of a drain hose can have significant repercussions for the equipment or person using it.
Here are some design features or challenges to keep in mind when designing a drain tube:
1) Do you need the part to stay open all of the time?
Use wire reinforced hose to keep it open at all times, but you will subject yourself to failure if the part is crushed.
Use a non-reinforced hose, like solid rubber, to allow for the part to collapse easily but also recover from that impact.
2) Would it be handy if you can kink the hose on purpose at times?
It can be handy to stop flow briefly in some applications by kinking the hose. A wire reinforced hose generally cannot do this, but a non-reinforced hose can.
3) Does it need to survive being run over by a fork lift, for example?
For most applications, there is a greater need for the hose to survive the occasional sever impact or crushing force (non-reinforced) than for it to remain open under mild pressure (reinforced).
1) Is it generally straight or does it need to curve around other features?
Ask about the bend radius of the hose.
2) Does an operator need to manipulate the hose?
If it is generally straight when in use you can get away with a thicker, heavier hose if needed. If it needs to be bent quite a bit, a lighter-weight reinforced hose or a non-reinforced hose should be chosen.
Even a heavy walled non-reinforced hose can still be flexible.
3) How often will it be flexed?
Some materials, especially multi-layer hoses, will not do well with constant flexing. Choose a solid rubber, urethane, or similar part in these cases.
1) How often is it draining material?
More regular use means you need a more robust material.
If the material is abrasive, consider that as well in terms of hose thickness.
2) Do you need a cap and plug assembly for on/off capability?
Many drain hoses offer caps as an option.
3) What happens to the hose when not in use?
Remember to keep storage in mind. Not all hoses will “stay put” when you try and stash them away. Even really flexible reinforced hoses can tend to return to “straight.” A non-reinforced hose is generally going to be best for this purpose.
1) How is it being connected to the main assembly?
A smooth collar or barb fitting would be the two most common options.
2) Do you need different methods on each end?
Stock tubing may offer limited connection options.
3) How permanent is this connection?
Do you need a friction fit or is a clamp required? What type of clamp will depend on if you want it to be removable or not.
1) Do you have extreme temperatures either in the setting or in the material flow?
Most plastics will be limited in their heat handling abilities. Multi-layer materials can be damaged more easily. Solid rubber is a great option for higher temperatures due to superior heat handling and the lack of expansion/contraction issues that multiple materials can present.
2) Are there corrosive materials involved?
Check with the manufacturer to make sure that the material meets your requirements here. Even things that seem innocuous can be trouble, so be sure to mention exactly what is going through the tube.
3) Is there aggregate or heavy particulate being drained?
Smooth bore tubes will be better when there is a lot of debris in the line. Non-reinforced tubes can have the advantage of being squished or massaged to get jams out of the tube without tools.
This is a good overview of issues and considerations for your next drain tube design project. Performance can vary quite a bit between different styles of hose and the material they are made from. Be sure to take careful inventory of your requirements in these areas and work with your supplier to find a practical and cost effective solution.