Quality standards required for hose clamps

1. The screw should be designed with a right-handed and single start thread which, when tightened without any additional locking device, allows the clamp to be reliably engaged and fastened to the part being connected.

2. The screw should firmly engage with the band. When necessary, the movable end of the band can be disengaged from the screw and can be opened to an opening equal to the maximum diameter of the hose to allow the clamp to be easily assembled to fasten at any point.

3. The screw must not come out of the hose clamp housing.

4. The movable end of the band should have a tooth groove and can extend for a sufficient length so that the clamp can work within the required clamping range. To ensure the clamping effect, the clamp with the smallest size within the clamping range is not recommanded.

5. The housing should not be able to separate from the band.

6. Each part should be polished, without burrs and sharp edges.

7.The strip should be flat and not twisted. The strip should be left rounded or rolled at the side.

8. The hose clamp is often galvanized to a minimum thickness of 5mm. The galvanized surface should not have any defects such as flooding points, holes, discoloration, peeling, peeling, pitting or roughness. Galvanizing should be carried out after welding and before assembly. Special surface protection should be consulted by the supplier and the customer.

Hose clamp quality test

Free rotation torque test

Requirement: Ensure that the lubricated clamp moves smoothly during free rotation and that the torque of the screw does not exceed 1.5 N-m when rotating in both directions.

Torque test

The clamp is mounted on a rigid mandrel (arbor) with a diameter equal to the nominal diameter of the clamp (nominal diameter). A torque test is carried out using a special torque testing device.

Tighten the clamp to 75% of the test value specified in the table below, hold for 2 min, then relax the load and inspect the clamp assembly with the naked eye; there should be no signs of permanent deformation or damage to the housing.

Re-apply the torque to reach the corresponding torque test value shown in the table below, permanent deformation or breakage should not occur.

Pressure resistance test

Test conditions:

At room temperature

The test medium is water or hydraulic oil at room temperature

Equipped with a hose with an outside diameter equal to the middle of the clamp range and the corresponding test device.

Test method.

The hose and the hose clamp are mounted on a smooth-surfaced metal mandrel matching the nominal diameter of each group of hose clamps. The torque used to tighten the band should not exceed 75% of the permissible torque test value for corresponding hose clamps as specified in the table.

During the test, the pressure should be increased gradually from low to high and the maximum pressure rise rate should be controlled to within 10⁵ Pa/s. When the added pressure is close to the corresponding permissible pressure test value for each group of clamps, carefully observe whether there is any liquid leakage or other faults at the joint between the hose and the arbor. The process lasts 1min, then continues to add pressure to reach the allowable pressure test value for each group of clamps as specified in the table, and no leakage or other faults should occur.

Label, packaging, transport, and storage.

1.Each hose clamp should have a permanent label (logo, size, material) stamped on the non-perforated part of the band or the top housing.

2.The name, logo, specification, quantity, weight and manufacturer of the product should be indicated/marked on the packing carton and box.

3.The finished product is cleaned and packed in a cardboard box with the logo placed in the same direction.

4.When packaging, the movable end of the band must not extend 12mm from the housing.

5.The cardboard box should be bundled up with plastic or nylon packing tape.

6.During transport, inversion is allowed whereas violent bumps and drops from heights are not.  

7. The finished product should be stored in a ventilated and dry place, not in direct contact with the ground, and not mixed with corrosive chemicals such as acids and bases.