Quality Control

A Filter material Inspection
The bag materials are normally received in rolls. Minimum the following tests be performed for each roll or suitable length
1. Examine the certificate from the felt material supplier.
2. Visual test of the surfaces.
3. Test of air permeability
4. Test of weight
5. Test of breaking strength, Mullen Burst
6, Test of thickness

B Visual inspection of the stitching work
No missing stitching or unbound threads are allowed and the stitching must be gas-tight.

C Bag flat width inspection
For the PTFE needle felt bags and woven glass bags, the flat width must be measured after the test cage has been inserted in to the bag and removed again. Perform as per step 1 & 2.
For the needle felt bags, the bag flat width can be measured without inserting the test cage into the bag.


D Length control/inspection
In order to minimize the length tolerance of the tube, ST Filter designed a unique digital cutting system to control the length of the filter tube. The tolerance can be strictly controlled by 200 pulses per second from the premium digital control system. Even for an 8 meter’s tube in vertical direction, ST Filter can control the tolerance in 2mm.

            Digital Length Sensor                               Length Inspection

        Tube length Control table                          Touch Screen controller

E Snap band/ plate hole inspection
By years of experience on filter bag manufacture, ST Filter has full sets of test plate holes from 120mm to 160mm in every 1mm. ST Filter can even make a new plate hole for special hole size.