Open reusable packer without check-valve to, as the name suggests, be reused in most boreholes. The reusable packer (GU) can also be used where communicated boreholes are suspected (leakage via cracking between boreholes) and/or for boreholes that require drainage in the time between packers being fitted and injection taking place.
The use of GU packers (multi-use packers) requires that packers can be loosened (removed) at just the right time when the grout has solidified so much that over-pressure no longer remains in boreholes, but that the grout has not hardened som much that the packers and injection pipes can still be cleaned (flushed) .
GU-packers are available for injection pipes in dimensions 3/8", 1/2" and 1". In addition to separate GU-packers presented in the table below (to fit on our standard injection pipes) the GU-packers can also be supplied on request directly mounted on the inner pipe of manual injection pipe (packer and pipe as a complete unit, often referred to as a sleeve). Direct-mount inner tube GU packers are available for inner tube sizes from 3/8" up to 1.5" for fast delivery, larger sizes available on request (see Special Products).
Do notice, reusable packers are not divided into high and low pressure variants.
NOTE: The maximum injection pressures given in the table below are only approximate values, the possible injection pressure is determined by friction between the packer and borehole (so that the packer does not slip). The material in the packer itself withstands higher pressures than indicated in the table, it is usually instead other components in the injection system that set the limit (such as hoses, valves, couplings).
Others: For 1/2"-GU packers mounting tools are available (for the key grip) see: Special tools packers under section Accessories Injection.
Open reusable packer for injection pressures up to approx. 100 Bar. As a reusable packer has non-return valve, injection pressure remains in packer and injection pipes all the way down to the ball valve after finishing the injection. Maximum injection pressure is thus limited by the type of ball valve on the injection pipe or the type of hose connection. The GU packer itself (inner tubes in packers, packer rubber and washers on packers) can withstand significantly higher pressures (+100 Bar). If GU packer is to be used for higher injection pressures than specified in the table below, special injection pipes with high-pressure valves can be ordered (low-pressure pipes but equipped with a high-pressure valve).
When injecting, consideration must be given to the friction of the packer against the rock, and if necessary, injection pipes must be secured before injection. When loosening the packer, the ball valve must always be opened first so that remaining over-pressure removed to avoid packing and pipe being pushed out of boreholes.
Suitable injection pipes are Mechanical Low Pressure pipe 1/2" or "Manual 1/2" Pipe" or Manual 3/8" pipe.
The table below shows: GMA's part number, GMA's model designation, What drillhole diameter the packer is intended for, What diameter the packer has before tensioning, What work span (sealing aperture) the packer has, What connection it is on the thread on the packer tube and tube dimension on ditto, Which approximately tightening torque required and approximate Maximum injection pressure*.
If more information is desired, we refer to the Technical data sheet (TDS) which is available as a PDF file to read/download.
Others: GU-packers are equipped with a "key grip" in the nose for easier installation/replacement of packs on injection tubes. GMA can offer a mounting tool for GU-packers, see further Accessories Injection: Mounting and dismounting tools.
* NOTE: Consideration must be given to rock type and hole direction to finalize maximum injection pressure. The table only shows what the packer itself can handle.
|
GMA part nr. |
GMA Model |
Drillhole Ø (mm) |
Outside Ø packer (mm) |
Work span |
Thread/dim. packer tube (Inch /mm) |
Tightening torque (Nm) |
Max injection pressure (Bar) |
|---|---|---|---|---|---|---|---|
| 8000528 | GU28 (CU28) | 28 | 27 | 27,5-30 | 3/8" (20x25) | 70-100 | ~100 |
| 8000530 | GU30 (CU30) | 30 | 29 | 29,5-32 | 3/8" (20x25) | 70-100 | ~100 |
| 8000532 | GU32 (CU32) | 32 | 30,5 | 31-34 | 3/8" (20x25) | 70-100 | ~100 |
| 8000534 | GU34 (CU34) | 34 | 32 | 32-36 | 3/8" (20x25) | 90-120 |
~100 |
| 8000536 | GU36 (C36) | 36 | 34 | 35-38 | 3/8" (20x25) | 90-120 | ~100 |
| 8000538 | GU38 (CU38) | 38 | 35,5 | 37-40 | 1/2" (25x3) | 90-120 | ~100 |
| 8000541 | GU41 (CU41) | 41 | 38,5 | 40-44 | 1/2" (25x3) | 90-120 | ~100 |
| 8000545 | GU45 (CU45) | 45 | 42,5 | 44-47 | 1/2" (25x3) | 90-120 | ~100 |
| 8000548 | GU48 (CU48) | 48 | 45,5 | 46-50 | 1/2" (25x3) | 100-120 | ~100 |
| 8000551 | GU51 (CU51) | 51 | 48,5 | 50-53 | 1/2" (25x3) | 100-120 | ~100 |
| 8000554 | GU54 (CU54) | 54 | 51,5 | 53-56 | 1/2" (25x3) | 100-120 | ~100 |
| 8000557 | GU57 (CU57) | 57 | 54,5 | 56-59 | 1/2" (25x3) | 100-120 | ~100 |
| 8000560 | GU60 (CU60) | 60 | 57,5 | 59-62 | 1/2" (25x3) | 100-120 | ~100 |
| 8000563 | GU63 (CU63) | 63 | 60,5 | 62-65 |
1/2" (25x3) 1" (36x3) |
100-120 |
~100 |
| 8000566 | GU66 (CU66) | 66 | 63,5 | 65-69 |
1/2" (25x3) 1" (36x3) |
120-150 | ~100 |
| 8000570 | GU70 (CU70) | 70 | 67,5 | 69-75 |
1/2" (25x3) 1" (36x3) |
120-150 | ~75 |
| 8000575 | GU75 (CU75) | 75 | 72,5 | 74-79 |
1/2" (25x3) 1" (36x3) |
120-150 | ~75 |
| 8000580 | GU80 (CU80) | 80 | 77,5 | 79-84 |
1/2" (25x3) 1" (36x3) |
120-150 | ~75 |
| 8000585 | GU85 (CU85) | 85 | 82,5 | 84-89 |
1/2" (25x3) 1" (36x3) |
120-150 | ~75 |
| 8000590 | GU90 (CU90) | 90 | 87,5 | 89-94 | 1/2" (25x3) 1" (36x3) | 120-150 | ~75 |
| 8000595 | GU95 (CU95) | 95 | 92,5 | 94-99 | 1/2" (25x3) 1" (36x3) | 120-150 | ~75 |
| 80005100 | GU100 (CU100) | 100 | 97,5 | 99-104 | 1/2" (25x3) 1" (36x3) | 140-160 | ~50 |
| 80005102 | GU102 (CU102) | 102 | 99,5 | 101-105 |
1/2" (25x3) 1" (36x3) |
140-160 | ~50 |
| 80005105 | GU105 (CU105) | 105 | 102,5 | 104-109 | 1/2" (25x3) 1" (36x3) |
140-160 |
~50 |
| 80005110 | GU110 (CU110) | 110 | 107,5 | 109-114 | 1/2" (25x3) 1" (36x3) | 140-160 | ~50 |
| 80005115 | GU115 (CU115) | 115 | 112,5 | 114-119 | 1/2" (25x3) 1" (36x3) | 140-160 | ~25 |
| 80005120 | GU120 (CU120) | 120 | 117,5 | 119-124 | 1/2" (25x3) 1" (36x3) | 140-160 | ~25 |
| 80005125 | GU125 (CU125) | 125 | 122,5 | 124-130 | 1/2" (25x3) 1" (36x3) | 140-160 | ~25 |
