Riverhawk Hydraulic Nut

hydraulic nut riverhawk photo

The design of the Riwerhawk Hydraulic Nut avoids bolt load torque inaccuracy from stud twisting as well as friction loss at the thread interfaces and nut face. The nut's compact size makes it an excellent choice where space is confined or when faced with envelope restrictions.

Even when tensioning multiple connected nuts, the Riwerhawk Hydraulic nut maintains a uniform compression of flanges, bearing houses, casings or connection rods.

Riverhawk has improved tensioning return of the nut to prevent erratic and excessive bolt loads. Furthermore, the hydraulic nut requires a minimal number of operators and facilitate fast and trouble-free installation – which translates to reduced operations costs.

Thread Diameter “A” Hydraulic Ram Area Maximum Hydraulic Load Nut Height “B” Nut Diameter “C” Maximum Stroke
inch cm inch cm lb kg inch cm inch cm inch cm
1.500 3.810 2.651 6.734 79,530 36,074 2.250 5.715 3.000 7.620 0.225 0.572
1.625 4.128 3.111 7.902 93,330 42,334 2.438 6.193 3.250 8.255 0.244 0.620
1.750 4.445 3.608 9.164 108,240 49,097 2.625 6.668 3.500 8.890 0.263 0.668
1.875 4.763 4.142 10.521 124,260 56,363 2.813 7.145 3.750 9.525 0.281 0.714
2.000 5.080 4.712 11.968 141,360 64,120 3.000 7.620 4.000 10.160 0.300 0.762
2.250 5.715 5.964 15.149 178,920 81,157 3.375 8.573 4.500 11.430 0.338 0.859
2.500 6.350 7.363 18.702 220,890 100,194 3.750 9.525 5.000 12.700 0.375 0.953
2.750 6.985 8.909 22.629 267,270 121,232 4.125 10.478 5.500 13.970 0.413 1.049
3.000 7.620 10.603 26.932 318,090 144,283 4.500 11.430 6.000 15.240 0.450 1.143
3.250 8.255 12.444 31.608 373,320 169,335 4.875 12.383 6.500 16.510 0.488 1.240
3.500 8.890 14.432 36.657 432,960 196,387 5.250 13.335 7.000 17.780 0.525 1.334
3.750 9.525 16.567 42.080 497,010 225,440 5.625 14.288 7.500 19.050 0.563 1.430
4.000 10.160 18.850 47.879 565,500 256,506 6.000 15.240 8.000 20.320 0.600 1.524
4.500 11.430 23.856 60.594 715,680 324,627 6.750 17.145 9.000 22.860 0.675 1.715
5.000 12.700 29.452 74.808 883,560 400,776 7.500 19.050 10.000 25.400 0.750 1.905
5.500 13.970 35.637 90.518 1,069,110 484,940 8.250 20.955 11.000 27.940 0.825 2.096
6.000 15.240 42.412 107.726 1,272,360 577,132 9.000 22.860 12.000 30.480 0.900 2.286
6.500 16.510 49.775 126.429 1,493,250 677,326 9.750 24.765 13.000 33.020 0.975 2.477
7.000 17.780 57.727 146.627 1,731,810 785,535 10.500 26.670 14.000 35.560 1.050 2.667
Supports tensioning of multiple bolts concurrently
Simultaneous “daisy-chaining” with uniform clamp loads and faster assembly
Withstand harsh environments
Tolerates applications up to 500°F / 260°C
Features water charging for special applications
Unique seal design of metal-to-metal
Features inherent safety
Accommodates confined spaces and envelope restrictions.
Forces act along bolt axis rather than through torque reaction arms
Compact standard sizes as well as custom Designs
Link multiple tools together for simultaneous tensioning
Each individual hydraulic nut is tested at max rated pressure before delivery
Every unit comes with a detailed instruction manual
Maximum hydraulic load is attained at nut pressure of 30,000 psi / 2,070 bar
The retained bolt can load up to 45,000 psi (3100 bar) preload stress in the thread tensile area
The alloy steel of the standard models maintains properties up to approx. 500°F / 260°C
Custom designs and materials are available if standard design doesn't accomodate your application

The installation of a hydraulic nut is quite straight forward. Usually, the nut fits within the space of the existing hardware and will not require additional thread length. Screw the hydraulic nut onto the stud and connect it to either a manual or air-driven hydraulic pump using flexible high-pressure hoses.

Pumping oil into the hydraulic nut generates a massive axial force, proportional to the pressure applied, i.e. the higher the hydraulic pressure, the greater a force generated. The force will compress the flanges and stretch the stud, thereby creating a gap between the retainer and cylinder of the hydraulic nut.

The operator turns the retainer down against the cylinder of the nut, which releases the hydraulic pressure. The retainer keeps the stud stretched within its elastic region, countering the stud's tendency to return to the original length. The two counter-acting forces thus create the clamp which holds the joint together. The complete tensioning process can be accomplished within two minutes.