Device for pressurizing a viscous fluid contained in a drum having an open upper end, the device comprises a base arranged to receive the drum and a follower plate which is vertically movable along an axis which is perpendicular to said base and passing through the center of the drum when the drum is on the base, said follower plate: - is supported by a motorized support system and is movable between a first position outside the drum and a second position inside the drum to exert pressure on the viscous fluid, - is configured to have the same dimensions as the drum opening, so that when the follower plate is in the drum its perimeter seals the drum, - has a transfer port intended to be connected to a pumping means which is capable of transferring the pressurized fluid, the device further comprising a resilient means for energy storage and restoration which is connected to the support system, said means being capable of storing energy when it is compressed under the effect of the pressure exerted by the support system when the pressure of the follower plate on the viscous fluid is greater than a certain predetermined threshold and to restore the energy to the follower plate when it is decompressed in order to maintain the pressure of the viscous fluid while the support system is at rest, the support system comprises: - a bracket which is movably mounted in a guide column, - two vertical guide tubes each attached to the bracket by a lower end comprising a fixed guide means, - two tie rods each having an upper portion inserted into one of the tubes via the fixed guide means and a lower portion, outside the tube, which is connected to the follower plate, - a means for moving the bracket in the guide column by a vertical translation movement so as to move the follower plate between the first position and the second position, the energy storage and restoration means comprises: - a compression element mounted on the upper portion of a tie rod, - a resilient element arranged in the tube between the compression element and a stop fixed with respect to the tube, said stop being closer to the lower end than the compression element, and - control means for starting and stopping compression of the resilient element by the compression element. - is supported by a motorized support system and is movable between a first position outside the drum and a second position inside the drum to exert pressure on the viscous fluid, - is configured to have the same dimensions as the drum opening, so that when the follower plate is in the drum its perimeter seals the drum, - has a transfer port intended to be connected to a pumping means which is capable of transferring the pressurized fluid, the device further comprising a resilient means for energy storage and restoration which is connected to the support system, said means being capable of storing energy when it is compressed under the effect of the pressure exerted by the support system when the pressure of the follower plate on the viscous fluid is greater than a certain predetermined threshold and to restore the energy to the follower plate when it is decompressed in order to maintain the pressure of the viscous fluid while the support system is at rest, - a bracket which is movably mounted in a guide column, - two vertical guide tubes each attached to the bracket by a lower end comprising a fixed guide means, - two tie rods each having an upper portion inserted into one of the tubes via the fixed guide means and a lower portion, outside the tube, which is connected to the follower plate, - a means for moving the bracket in the guide column by a vertical translation movement so as to move the follower plate between the first position and the second position, - a compression element mounted on the upper portion of a tie rod, - a resilient element arranged in the tube between the compression element and a stop fixed with respect to the tube, said stop being closer to the lower end than the compression element, and - control means for starting and stopping compression of the resilient element by the compression element.