Vacuum Hoses

In the central material feeding (zentrale Materialversorgung) systems of the plastics processing industry, PVC hoses are frequently used in the vacuum area. PVC hoses are very rigid and do not collapse (cave in) under vacuum.

The easiest and quickest way to fix the hoses is with hinged bolt clamps (Gelenkbolzenschellen). A more economical alternative is worm drive clamps (Schneckengewindeschellen).

Available in 4 different diameters (Ø 40.0 – Ø 60.0 mm).

The one critical property of a vacuum hose: not collapsing

Unlike a conveying hose, no material passes through a vacuum hose; the pressure inside it is lower than outside. This forces the hose to collapse inwards. A hose that is not rigid enough shrinks under vacuum, its cross-section narrows and it lowers the system efficiency — this narrowing is usually not visible to the eye, and is noticed only as a loss of performance.

That is why PVC hoses are widely used on the vacuum side: their construction is rigid and, with their spiral reinforcement, they resist collapsing.

How the symptom is recognized

When the vacuum capacity drops, the pump is usually the first suspect. Yet the frequently encountered causes are these: a hose that has aged and softened, a cross-section crushed at a sharp turn, or a leak at a connection point. Squeezing the hose by hand to compare it with its former flexibility is a simple but useful check.

Installation rules

• Avoid sharp turns; observe the hose's minimum bending radius
• Do not stretch the hose; leave an allowance for thermal movement
• Protect the sections that rub on the floor; external wear also weakens the cross-section
• A longer hose than necessary increases the pressure loss — the line is kept as short as possible

For the lines through which the material is carried, conveying hoses are used.