The Gravity Drilling Technology also includes networks made of PE pipes. One of such projects was the construction of a sanitary sewage connection for a single-family residential building in the Redłowo estate in Gdynia. The installation of the PE-RC DN160 pipe should be 37 meters long, with a 5.5% gravity drop, between the existing DN1200 well and the excavation.

In the case of this project, it was difficult to locate the pipeline among dense built residential buildings and home gardens. In the area of work, there was a significant slope of the terrain and slopes limiting the maneuvering of any construction equipment.

Initially, it was assumed that the installation would be performed with the use of a HDD drilling rig, but due to the above-mentioned field inconveniences, the company declaring execution with the use of HDD eventually withdrew from the implementation after an on-site visit. The installation was considered with the use of a pneumatic jacking machine, commonly known as a mole. However, there was a high risk that the jacking technology, uncontrollable and without the possibility of locating and possible corrections of the planed trajectory, on a length of 37 meters, would fail. The mole would not hit the well and we would not get the desired drop. In addition, vibrations and shock caused by the mole's work may cause damage to neighboring buildings and other facilities such as retaining walls and brick fences. We know of projects in which the use of a mole for a typical culvert under the road caused damage, cracks in the facades of buildings adjacent to the works. The strength of such an impact can be approximated on the basis of the ability to transmit vibrations through a given soil medium, but it is associated with additional expertise and soil tests. The use of a mole in such a close development is a high risk related to possible claims for possible damage. Moreover, such work would be very troublesome. It was impossible to install the pipeline using an open trench, due to the co-location of the installation with a 1.5 meter wide technical belt belonging to the city. In the end, it turned out that the technology with the use of the Gravity Drilling Rig is the only effective and most economical solution for this project.

The advantage of the Gravity Drilling technology, apart from the efficiency in drilling and accuracy in the implementation of precise installations, is also the mobility of the devices included in the drilling set. All devices are placed in a compact container. This allows you to carry out work virtually anywhere, even densely built-up and with difficult access.

As part of the construction by the Investor - the Robyg company, of a complex of residential buildings "Zajezdnia Wrzeszcz", located at Bolesława Chrobrego Street in Gdańsk, was built a rainwater drainage system. The length of the installation was 15 meters, with a design slope of 2%. PP Modular Pipes with a diameter of 225 mm were used.

The course of the installation covered the area between the existing sewerage well, located in Bolesława Chrobrego Street, and the starting chamber, located on the construction site of a residential complex.

Originally, the installation was to be made using other trenchless technologies, including the installation of a steel casing pipe with a jacking machine, the so-called mole, due to lower costs. However, potential contractors withdrew their offers, mainly due to insufficient space for the starting chamber. The second important reason was the need to perform the installation with very high precision, resulting from the vicinity of the underground water supply system running in the construction area. The sewage system under construction was to run a dozen or so centimeters away from the water supply system. Damaging it would cause serious problems and additional significant costs.

In the first stage of the installation, a drilling was made from the starting chamber, in which a sewage well DN 1200 was first built, and then a Gravity Drilling Rig was installed.

After reaching the final well, with the retooled machine, the pulling of the pipe, built of successive segments of Modular Pipes, was started. Previously, of course, it was necessary to drill a hole made with a pilot drill, using a core drill adapted to the diameter of the pipe to be installed. In this case, this activity was abandoned due to practical tests of the new solution of reaming heads. Most of the typical sewage chambers can be easily drilled with just such a head. The problem can only occur in wells with low mechanical strength, where the use of a reamer instead of a core drill may damage the well components. One of the advantages of the Gravity Drilling Rig technology is overcoming hard obstacles, including well construction elements, not by using the force of pushing or pulling the machine, but by properly selecting the geometry of the drill head and the ability of the machine to fully and smoothly control all operating parameters during drilling.

One of the advantages of the Gravity Drilling technology is the ability to work only within the sewage wells involved in the installation. The Modular Pipes we use allow them to be joined in a place limited by the well. The connection itself is effective, tight and durable. We connect the individual pipe segments using a hydraulic squeezer that presses one end of the pipe into the other.

Finally, just before reaching the starting well, a reaming of the well wall is made to allow the installation of the pipe to be introduced into the starting well.