Common Questions During the Use of FRP Membrane Housings

The thrust cone is installed on FRP concentration port. Firstly, please install the head seal, bearing plate, F/C Port and adapter together. Next, please insert the small diameter port of the thrust cone vertically at one end of the mounting adapter and stick into the slot on the head seal whose surface is umbrella-type.

There could be following several situations:

1. The Dirty or Invalidation of Membrane Elements

   Solution: Please contact and consult with the manufacturer about the solutions of cleaning and replacing membrane element.

2. The Damage of the Joint Pipe, End Cover Adapter or Permeate Port

   Reason: The reason may be that there is a large gap between the membrane element and the end cover. Another reason may be that the system fails to take measures to ensure slow pressurization at startup or slow pressure relief at shutdown. The membrane elements in the membrane housing collide with each other under pressure and cause damage to the joint pipe or adapter.

   Solution: Please read the related content of opening the membrane housing and replacing the membrane elements in the user guide. Please remove the end cover and membrane element and check all fittings for damage. If the fitting is damaged, please replace the damaged fitting. If you need to reinstall fittings, according to the related content of installing membrane elements in the user guide, please install adapter shim to reduce the gap between membrane elements or between the membrane and the end cover. Before you restart the system, please check if the system is equipped with a control device which can ensure slow pressurization and slow pressure relief. If there is no have the control device, please add a similar device before starting the system.

3. The Seal Ring Damage of the Membrane Element Joint Pipe, Adapter or Permeate Port

   Solution: Please open the membrane housing and replace the damaged seal ring according to the related content in the user guide.

The crescent film of 2.5” membrane housing and 4" membrane housing in Winder^® series and the link stopper of the 8" membrane housing in AOWY series may be unable to take out. There may be the following several reasons:

1. The stopper is blocked with dirt and cannot be removed.

   Solution: You can use warm water and penetrant to smear the dirty stopper area separately. The soak time is 2 to 4 hours. Next, you can use a rubber hammer or a stick to beat the bearing plate. After the dirt is loose, you can take out the stopper by using the straight screwdriver or other tools. It is worth noting that please don't soil the membrane elements when you are using the penetrant.

2. The bolt head or thread of the stopper are damaged and cannot be removed.

   Solution: Cut off the stopper bolt.

   Tools: Angular finishing grinder, cutting tablets, power line, electric drill, screw tap and stainless steel drill

Specific operation:

1. Please cut the stopper bolt by using the angular finishing grinder. Don't damage the bearing plate, FRP housing and clear water outlet during cutting. Protective equipment such as headgear must be worn.
2. Next, please take out the uncut bolt from the bearing plate by using the electric drill whose stainless steel drill diameter is 6 mm. It is worth noting that please don't damage thread in the screw hole of the bearing plate.
3. Then, please remark the thread by using the screw tap.
4. Finally, please clean sediment with clear water.

Reason: The reason may be that the housing is damaged, the corrosive medium leaks to the bearing plate and corrodes it.

Solution: Please hand leakage problem according to the related content in the user guide. Next please disassemble and change the bearing plate according to the related content in the user guide.

The pH range of tolerable media of conventional membrane housings in Winder^® series and AOWY series is 3 to 11. The membrane housing should not be used beyond the tolerance range. Otherwise, the housing may crack due to corrosion. Most cracks appear in the opening of the membrane housing. If you find any cases of corrosion cracking, please contact Hebei Cheng Da Pipes Co., Ltd.

Note: If you find any leakage of F/C port, please contact Hebei Chengda Pipes Co., Ltd. in time.

If you find the F/C port is leaking and you need to remove the F/C port, please follow these steps:

1. Please opening the membrane housing according to the related content in the user guide.
2. Please draw off the water and remove the F/C port clamp and pipeline.
3. Please remove the F/C port retainer by using a screwdriver.
4. Please pave an anti-shock mat inside the membrane housing to protect the internal surface from damage owing to the shedding of F/C port.
5. Please beat and remove F/C port in the membrane housing through following the side port direction.

There are several possible causes of the leakage situation:

1. The sealing ring is not properly installed, so the position is offset.

   Solution: Please remove and reinstall the sealing ring.

2. The sealing ring is aging and damage.

   Solution: Please contact Hebei Cheng Da Pipes Co., Ltd to replace the sealing ring.

3. The F/C port is damaged owing to corrosion issues. The seal groove is scratched.

   Solution: Please replace and reinstall the F/C port according to the related content of reinstalling in the user guide.

Note: Don't scratch the internal surface in the side port of the membrane housing when you install the F/C port. After installation, if the F/C port whose bottom surface is saddle-shaped is exposed to the housing surface, please rotate 90 degrees and reinstall the F/C port.

1. If the F/C port of membrane housing (side port) leaks water, the reason may be that there is a gap between side port and membrane housing.

   Solution: Please contact Hebei Cheng Da Pipes Co., Ltd to replace the membrane housing.

2. If not the above circumstances, it may be that the F/C port doesn't match the piping.

   Solution: Please adjust the position of the membrane housing and piping so that the F/C port and its connecting pipe are installed correctly according to the related content in the user guide.

There are several possible causes of the leakage situation:

1. The connection pipeline does not match the thread of the permeate port

   Solution: Please check the thread of the permeate port and the connection pipeline by using an appropriate screw gauge and judge whether the permeate port matches the connection pipeline. If not, please replace and change the pipeline joint.

2. The pipe plug or the thread of permeate port connection pipeline are not twisted.

   Solution: Please remove the pipe plug or pipeline and clean the wastes on the thread. Then, please wrap 2 to 3 layers of Teflon tapes on the pipe plug or pipe joint and reinstall to the permeate port. When you operate, please don't use too much torque. Otherwise, it may damage the permeate port. Typically, the maximum torque is 15 Nm. A tight torque of 50% of the maximum torque is appropriate.

3. The permeate port is cracked.

   Solution: Please remove and dismantle the end plate and check if there is a crack on the thread of permeate port. If yes, please replace the permeate port and reassemble and reinstall end plate according to the user guide.

1. There are several possible situations of the leakage cause:

   This reason is the most common. The handling methods are as follows:

   1. Detect the components, temperature and pH of the medium to determine whether the seal ring is aging or damaged due to the medium. If so, please adjust the pretreatment system or change the material of the seal ring.
   2. Check the seal ring lubricant composition and judge if the seal ring is swollen due to improper use of the lubricant. If so, please replace the seal ring lubricant. We recommend the use of glycerine as a sealing ring lubricant.
   3. Replace the new seal ring according to the user guide.

2. The sealing plate is cracked or there are scratches or foreign matters in the sealing groove on the sealing plate.

   1. Remove and disassemble the end plate according to the installation guide.
   2. Check if the sealing plate is cracked. If so, Please replace the new sealing plate.
   3. Check there are scratches or foreign matters in the sealing groove on the sealing plate. If there is a deep scratch, you need to replace the new seal plate. If there is a slight scratch, you need to use waterproof abrasive paper whose mesh numbers should exceed 500 to grind the scratch. If there is dirt or other foreign matter, you need to clean the sealing plate according to the installation guide.

3. Scratches or foreign matters in the sealing area of the internal surface of the membrane housing

   1. Open the membrane housing according to the related content of the installation guide.
   2. Check there are scratches or foreign matters in the sealing area of the internal surface of the membrane housing. If there is a deep scratch, please contact our after-sales team. If there is a slight scratch, you need to use a waterproof abrasive paper whose mesh numbers should exceed 500 to grind the scratch. If there is dirt or other foreign matter, you need to clean the membrane housing according to the installation guide.

4. Due to there is a gap in the lateral wall of the membrane housing, the medium seeps from the end shear groove along the fiber.

   If the above 1, 2, and 3 water leakage reasons are excluded, the nozzle should be potted. The specific operation methods are as follows:

   Material: special sealing glue of Chenda company, acetone or alcohol.

   Tools: straight screwdriver, plastic rod or rubber hammer, wooden block or plastic block, clean cotton yarn, hair dryer.

   Specific steps:

   1. Open the membrane housing according to the related content of the installation guide.
   2. Drain away water and disassemble the clamp and pipeline of F/C port.
   3. Remove F/C port retainer by using a straight screwdriver.
   4. Please pave an anti-shock mat inside the membrane housing to protect the internal surface from damage owing to the shedding of F/C port.
   5. Please beat and remove F/C port in the membrane housing through following the side port direction.
   6. Please polish the surface of the opening with water sandpaper of 320 mesh or more, remove the impurities, wipe the internal surface of the side port with clean cotton yarn, acetone or alcohol and blow the opening with a hairdryer.
   7. Apply the sealing glue evenly to the edge of the concave surface at the opening.
   8. Apply the sealing glue to the upper surface of the convex part under the side port. Be careful not to apply the glue to the sealing ring.
   9. Apply glycerin to the sealing ring, then place the side port into the opening of the membrane housing, and block it under the side port with a wooden block or plastic block to avoid accidentally injuring the side port and internal surface when installing the side nozzle. Tap the side port with a plastic stick to correctly install the side port. Don't damage the internal surface when striking.
   10. Install the retainer.
   11. After installing the side port, the edge of the concave portion under the membrane housing opening is continuously filled with the sealing glue. The gap between the side port and the internal surface of the membrane housing is filled. It can ensure that the cross-section of the opening of the membrane housing is coated with the sealing glue.
   12. Clean the sealant bu using clean cotton yarn with acetone or alcohol.
   13. Allow standing for 6 to 8 hours. After the sealing gel is fully cured, please close the membrane shell according to the installation guide.

If the finishing coating of FRP membrane housing has slight damage during transport and installation and the coating is not penetrated, you can adopt the following methods to repair:

Material: eco-friendly water paint and additives.

Tool: spray gun, 500 mesh water sandpaper and clean cotton yarn, etc.

Specific operations:

1. Please use 500 mesh water sandpaper to polish and remove the topcoat on the damaged area and the surrounding area.
2. After drying, please clean the coating surface to ensure that the spray surface is smooth and clean.
3. Please match eco-friendly water paints and auxiliaries according to the operation time (please contact us for the specific ratio).
4. Please use fabric or other materials to cover the F/C port and areas that are susceptible to paint mist.
5. Please spray the sanding area. The spraying area should be intact without sag, color light, and the thickness should be uniform. The thickness should be controlled at 80 μm to 120 μm.

Visually inspect the integrity of the topcoat film. Then dry it according to the paint cure time (120 °C for 2 hours or room temperature for 24 hours).

In general, we only recommend that the accessories we sell are used on the membrane housings we produce. Although the accessories we produce look similar to those accessories produced by other companies, installing our accessories on the membrane housings of other companies may have errors in size and tolerance. This operation can lead to leakage problems during using membrane housing. Therefore, we suggest that you choose to purchase the original model membrane housing accessories of the original factory or re-purchase a set of membrane housing products. If you insist on purchasing accessories separately, we recommend that you first purchase a set of accessories to test, and if there are no problems, then make bulk purchases.