Process water storage tanks

Above-ground steel process tanks are made of twisted sheets of galvanized corrugated steel. We design and manufacture roofed and open tanks that can be used to irrigate fields and crops or to store large volumes of process water. Process tanks are equipped with pipes enabling efficient and effective distribution of water for production or agricultural purposes. We also make process tanks for raw and hot water storage, which are used in the energy, chemical and production industries.

We are able to provide steel ground process water storage tanks with a wide range of dimensions and capacity. You can easily match the appropriate tank to the specificity of the installation place, design requirements, operating conditions or its assignment.

It is possible to design and manufacture tanks with non-standard dimensions and capacities.

Steel above-ground process water tanks designed and manufactured by our company consist of the highest quality hot-dip galvanized steel elements. The coat of the tanks is made of individually twisted steel sheets of standardized dimensions. The thickness of the steel panels depends on the standard of execution and the dimensions of the tank. The parameters of the metal sheets are selected on the basis of previously made strength and static calculations.

The metal sheets that make up the structure of technological tanks are made of double-galvanized S350GD steel, coated with a zinc coating Z275, Z350 or Z600. The steel panels are drilled, so that vertical and horizontal joints between the sheets could be screwed together.

Thanks to the optimal selection of the zinc coating supported by design calculations, we are able to design and manufacture durable tanks with the longest possible service life. During the calculations, we calculate the design service life of the tank structure based on the corrosivity class in the location the tank will be installed. The upper and lower edge of the tank body is equipped with a peripheral angle, which ensures rigidity and durability of the structure.

All steel structural elements and additional equipment of steel above-ground process tanks are protected against corrosion using the hot-dip galvanization method. Thanks to the zinc layer, it is possible to comprehensively protect the tank against adverse weather conditions. Additionally, at the customer's request, we can paint the outer parts of the shells of the tanks using the electrostatic method. In this way, the tanks get an additional layer of protection.

The roof of the steel above-ground tanks is made as a self-supporting structure on steel "Z" beams with an outward slope. The roof structure ensures efficient and effective removal of snow and rainwater outside the tank.

The roof of a tank can be equipped with an insulated or non-insulated roof covering. The insulated cover is made of T35 trapezoidal sheet metal or sandwich insulated panels with a mineral wool core, PIR foam or polystyrene. The covering width of the roof panels is 1150 mm, which ensure quick, simple and convenient installation to the roof structure using pass-through fasteners. The tongue-and-groove locks make the roof structure tightly connected to the structure of the steel ground process water storage tank. If necessary (according to the statistical and strength calculations results) we additionally use peripheral system clamps, the so-called "wind reinforcements". Providing easy access to the tank roof, we install a steel ladder with platforms on the structure. The roof of a tank is topped with a manhole, which enables the inspection of the inside of the steel process water storage tank.

As part of the waterproofing protection, we use a prefabricated EPDM membrane or a PVC film welded at the construction site. Each of these solutions eliminate the risk of contact of the stored water with a thermal insulation or steel walls of a tank, thus preventing corrosion centres.

EPDM membrane

  • thickness: 0,75mm -1,00 mm, 
  • guaranteed service life of min. 30 years, 
  • very good properties in terms of expansion and contraction in the range of up to 300% elongation, 
  • delivered to the construction site in the form of a ready-to-install bag, adapted to the dimensions of the tank, assembled on site, 
  • 14 days for replacement in case of leakage.

PVC film

  • thickness: min. 1,5 mm, 
  • guaranteed service life of min. 35 years, 
  • high resistance to mechanical damage, 
  • vulcanized on construction site,
  • 24 hours for replacement in case of leakage.

The membrane is protected against puncture by a geotextile with a minimum density of 150 g / m2, laid directly on the tank basis.

The thermal insulation of steel aboveground process tanks consists of internal or external insulation and anti-frost protection.

External insulation

External insulation is used in the case of aboveground steel process tanks covered with corrugated or trapezoidal sheet. The walls of the tanks are insulated with 100 mm thick mineral wool and additionally covered with a galvanized trapezoidal sheet. Instead of galvanizing, the trapezoidal sheet can be painted in a color selected from the RAL palette.

Internal insulation

Installed on the roof and walls of the tank. Usually it is made of EPS boards not less than 60 mm thick or XPS boards 40 mm thick. The plates are installed with screws between the membrane and the construction plate inside a tank.

Anti-freeze protection

Steel above-ground process water storage tanks are usually equipped with anti-freeze protection, consisting of 2-3 independent heating batteries with a thermostat, which generates power from 3 to 6 kW. The heating batteries operate in a three-phase system (400 V power supply). The degree of protection of the thermostat terminals and electrical connections has the IP 67 standard.

The heaters are equipped with automatic thermostats that regulate and maintain water temperature in tanks at a level not lower than 5oC. If the heater fails, it is not necessary to empty the tank completely.

Aboveground steel process tanks are equipped with automation and control systems. One of them is a system that monitors 4 water levels. This system consists of internal conductance probes suspended at appropriate levels of the tank. The signals generated by the probes are led to the relay implemented in the switch cabinet.

On the roof of the tank, there is a Pt100 sensor suspended 1 m from the roof level, which continuously measures temperature. The sensor transmits an analog signal about temperature inside the tank to the controller implemented in the switch box.
Water level monitoring system monitors water level in a tank in 4 preconfigured modes:

  • Minimum level - level of the minimum tank filling, which signals starting of emptying a tank to the lower dead zone. The probe informing about this mode is placed 50 mm above the edge of the suction pipe anti-vortex plate. An alarm triggered by a probe indicating the minimum level, prevents the pumps from dry running (running without water).
  • Intermediate level - level of half (50%) filling of the tank. It is useful to be signaled during service and repair works on the tank. The intermediate level may indicate a different water level.
  • Maximum level - the level of the maximum permissible filling of a process water storage protection tank. Lowering the maximum level is a signal that the water system is out of order. If the water level drops below the maximum level, the automation system will turn off the heaters.
  • Overflow level - the level of the highest, alarm filling of a tank. If a process water storage tank reaches such a level of the water surface, it means that the float valve fails. If the overflow level is reached, the water from the tank may overflow.

levels of water level monitoring system are signaled with red lamps in the tank operation controller located in the switch box.

The water tank controller is usually installed on the wall, outside of the tank. It enables constant monitoring of the tank's efficiency. If any irregularities are detected, an alarm is triggered to inform about the occurrence of faults or failures. The device complies with the IP 65 standard.

The heating system turns on automatically when the water temperature in the tank drops below 5oC and turned off when it reaches the temperature of 6oC. If water in the tank reaches temperature of 3oC, the heating control system will signal the failure with a red "low temperature" indicator. The heaters turn off automatically when the water level in a tank drops below the maximum level. This is to protect the internal insulation layer of a tank.

Steel above-ground process water storage tanks are equipped with the necessary design equipment. The equipment is properly installed according to the standards requirements.
The standard equipment of ground process water storage tanks consists of: 

  • supply pipeline terminated with the so-called free outlet, 1-2 automatic float valves responsible for automatic filling of the tank (not required by law), 
  • suction pipeline with double anti-vortex plate,
  • overflow pipe, 
  • drainage pipeline with a manual shut-off damper. 

Each pipeline may be led through the foundation or tank wall, according to the requirements.
Process water storage tanks are additionally equipped with: 

  • electrical switchboard, water level probes and heaters, 
  • bottom service hatches (if required),
  • in accordance with the current health and safety regulations, steel cage ladders leading to the roof, platforms with protective barriers, service hatches on the roof.

Designing

Before delivering the process tank to the site and its installation, we make a detailed design of both the tank and the foundation slab. Along with the detailed design, we provide the necessary documentation, which includes, among others a design of a tank construction.

Delivery

After designing a process water storage tank we deliver it with the necessary equipment and unload the tank at the construction site or in the customer's warehouse. Usually, the day of delivery is a day of assembly start-up.

Assembly

Our team of 3-4 people assemble the tank by means of external hydraulic pistons. The steel structure with internal insulation, membrane and equipment is sequentially installed. The tank is fixed to the foundation plate with anchors. The foundation plate is also the bottom of the process tank.

Leak test

After the assembly is completed a tightness test is performed. It consists of filling the tank to a height of approx. 1.5 m. At this stage the tightness of the pipelines flanged connections are checked. In the second tightness test, a tank is filled in to its nominal capacity. The second leak test lasts 24 hours and allows us to verify the tightness of a tank accurately.

Electrical devices commissioning

When a tank is already finished an electrical devices are stared-up. Our experts verify the correct operation of electrical devices and installations along with the automation systems necessary for the correct operation of a process tank.

Warranty

The whole works are completed with the delivery of as-built documentation with the materials approvals and a warranty card.

Thanks to the developed tank assembly system, we are able to significantly reduce the need for heavy equipment and we can install the tank in the shortest possible time.

1. Step - site preparation

In the first step, we prepare the area for pouring a concrete foundation slab on which the tank will be installed. During this stage of works, we pour the slab and deliver all the necessary building and construction materials to the construction site to erect the tank.

2. Step - tank assembly

In the next step of works, qualified employees of SD Tank Sp. z o.o. start assembling the tank on a dry and ready-to-install foundation plate. Our tanks are installed using external hydraulic pistons. The steel structure of a tank is assembled in stages along with the simultaneous installation of the internal insulation, membrane and the tank equipment.

3. Step - finishing works

In the third step of a process tank assembly, an external piping of a tank with its optional additional equipment is installed. After this assembly step, we proceed to leak tests, start-up of electrical devices and issue as-built documentation. 

We provide a 5-year warranty for a tank construction and a 24-month warranty for mechanical and electrical devices. In order to maintain a warranty, it is necessary to perform at least one technical inspection with cleaning the membranes in the third year of operation of a tank from the date of its first filling with water.

You can extend the standard warranty period up to 15 years on the basis of a Full Service Contract.