Static Mixer

• Nozzle 2.6 test 1 → somewhat shorter needle with static mixer and water
• Long test with water. Systems check at different levels.
• Measures discharge of different systems.

• Nozzle 2.6 test 2 → somewhat shorter needle with static mixer and accelerator
• Volume of water in hoses to accelerator.
• System clogged within 5:00 minutes.

• Nozzle 2.7 test 1 → without static mixer and accelerator
• System clogged within 1:40 minutes

• Nozzle 2.8 test 1 → needle with short tube and accelerator
• Stopped test after 1:25 minutes.
• Clearly slow buildup of hardened concrete.

• Test 1 - 1:1 Masterroc (167) 2 l/h + Duomix + HP 2.0 + Possolit retarder .1% (premix w.)
• Test 2 - 1:1 Masterroc (167) 3 l/h + Duomix + HP 2.0 + Possolit retarder .1% (premix w.)
  • ratio water 0,18 van 0,17 (water tot premix)
• Test 3 - 1:1 Masterroc (167) 4.5 l/h + Duomix + HP 2.0 + Possolit retarder .1% (premix w.)

• Test 1 - 1:1 Masterroc (167) 2 l/h + Duomix + R130 retarder .5% (premix w.) (6-bar DT_1) (no mixing ACC)
• Test 2 - 1:1 Masterroc (167) 2 l/h + Duomix + R130 retarder .5% (premix w.) (2-bar DT_1) (new batch ACC)
• Test 3 - 1:1 Masterroc (167) 2 l/h + Duomix + R130 retarder 1% (premix w.) (2-bar DT_1) (old batch ACC)
• Test 4 - 1:1 Masterroc (167) 2 l/h + Duomix + R130 retarder 1% (premix w.) (2-bar DT_1) (old batch ACC)
• Test 5 - 1:1 Masterroc (167) 2 l/h + Duomix + R130 retarder 1.5% (premix w.) (2-bar DT_1) (old batch ACC)
• Test 6 - Amersfoort accelerator (Variable print-speeds and percentages ACC / Mortar)
  • 0.16 Water
  • 0.15 Water
  • 0.15 Water

We looked at the previous tests and in particular the second 'bucket test'. The data gathered from this test was very useful. The tentative conclusion is that mixing is going well and that the needle solution is working, but that the reaction is so severe that the pressure increases too quickly which causes a backwash in the needle and clogs the system completely.

It is difficult to get the consistency right without the Duomix. Since Cugla delivered the new batch of material, we have to add an extra 150ml of water per 25kg. Today we found a lot of hard pieces in between the find of the static mixer. This is problematic.

We need to during the following tests whether adding more retarder might the solution.

• More retarder
• Test Duomix M300
• Make more needles at All Metal
• No leakage
• New version of the NMS doesn't work

Comment: DT 3 was turned off (this influenced readings DT 2 and DT 1)

Test results: More retarder results in more fluctuations of the pressure in DT 2 The print hardened irregularly. (To the left instead of the right side of the nozzle layer). The buffer tank of the retarder started to leak because of the pressure buildup. Water / accelerator transition can cause instability / spraying.

• Buffer tank broke and was leaking.
• Hard piece found in the middle of the static mixer while cleaning. Is probably stuck.
• No problems with overheating.
• Air bubbles in the mixing accelerator.
• Water cleaning system works in principle.
• Angled needle injection is working.
• Fail because of high pressure (approximately 14-17 bar)

• DT 3 not working.
• Filter for temperature sensor may be needed. A few incorrect data points showed upa
• Implementing communication is the next step.

• Bad supply of dry material. (Shaker solution.) At this moment it is sticking to the sides.

Exciting! Material consistent.

Comments:

• Problems with the development of accelerator pockets from the nozzle head. This causes the accelerator to 'spray away' from the nozzle.
• Duomix rotor stator became problematic towards the end of the test.
• The rotor stator is clogged at the top (not at the bottom!).

Test results:

Higher pressure in DT 1 is not related to the accelerator pockets. This is not caused by air in the accelerator. The accelerator pockets are still developing with a new batch of accelerator. Retarder mixed with the water resulted in a more homogeneous pressure. Prints with more retarder suffer from this less. An increase in the amount of retarder resulted in a more stable reading and has a positive effect on nozzle clogging.

• 2020_05_26-20210126t142014z-001.zip
• 2020_07_09-20210126t142035z-001.zip
• 2020_08_12-20210126t142049z-001.zip
• 2020_10_01-20210126t142059z-001.zip