Hopper Scales

Vessel weighing systems (also referred to as silo weighing systems, tank weighing kits, or tank weighing assemblies) are the most accurate method of determining the quantity of material in tanks, silos, mixers, and industrial reactors. Unlike level measurement methods based on capacitive, radar, or ultrasonic probes, gravimetric weighing is entirely independent of the physical properties of the material. It makes no difference whether the medium is a powder, granulate, liquid, or gas — the measurement method remains accurate even for dusty, foaming, corrosive, or low-dielectric-constant materials.

At InterProcess, we design vessel weighing systems on an individual basis — both for newly constructed and existing tanks. Strain-gauge load cells are mounted directly in the tank supports, using appropriate load transfer elements, check rods, restraints, and weighing terminals. Furthermore, where existing installations are being retrofitted, it is possible to equip the supports with extensometers, which enable mass measurement without any structural modification to the tank.

A typical silo weighing system consists of strain-gauge load cells mounted in the tank supports, mounting assemblies (weigh modules) ensuring correct load transfer, a signal summing junction box, and a weighing terminal (integrator). The strain-gauge load cells — most commonly operating on the shear beam or compression principle — generate an electrical signal proportional to the applied load. The signals from all load cells are summed in the junction box and then processed by the weighing terminal to produce a mass reading in kilograms or tonnes.

A key aspect of correct vessel weighing system operation is the elimination of lateral forces, which may arise from rigid connections between the tank and pipework, ventilation ducts, or other plant components. By using appropriate mounting assemblies with load transfer elements, check rods, and restraints, these forces are compensated for, ensuring accurate measurement regardless of the surrounding conditions.

Every tank weighing kit is designed individually and comprises the following elements:

Vessel weighing systems, depending on the controller used and the system configuration, perform a wide range of functions. The most commonly used operating modes are: continuous tank mass measurement with live fill-level display; material intake and discharge with simultaneous batching (recording of quantities received and dispensed); and automatic weighing and dosing of preset batch quantities in batch mode.

Furthermore, modern weighing assemblies enable control of actuators — valves, feeders, gates, and pumps — directly from the weighing terminal. Through communication with supervisory control systems (PLC, SCADA), the silo weighing system becomes an integral part of the plant’s process automation, enabling mass change data logging, production report generation, and remote tank level monitoring.

If your application requires precise material dosing with active flow regulation, please refer to our range of gravimetric feeders and belt feeders.

We design vessel weighing systems for virtually every type of industrial vessel. The type of vessel determines the selection of appropriate load cells, mounting assemblies, and the method of lateral force compensation. We most commonly supply weighing systems for storage tanks and silos (bulk materials, granulates, powders — from a few hundred kilograms to over 100 tonnes), process vessels and mixers (with agitators, vibrators, or other dynamic elements requiring force compensation), chemical reactors (with pipework connections and heat exchangers — requiring flexible connections), liquid tanks (milk, chemical liquids, fuels — requiring corrosion-resistant materials), and hoppers and feeders (as part of a gravimetric dosing system, e.g. in loss-in-weight feeders).

Silo and vessel weighing systems are used across a wide range of industrial sectors. In the food and feed industry, they are used for raw material stock control in silos (flour, grain, sugar, animal feed) and for dosing recipe ingredients in mixers. In the chemical and pharmaceutical industries, they enable precise reagent balancing, reactor level monitoring, and production process quality control. In the construction and cement industries, silo weighing kits are used for stock control of cement, lime, and aggregates. In logistics and warehousing, vessel weighing systems enable automated stock monitoring and order generation when minimum material levels are reached.

Why is weighing better than level measurement?

Gravimetric weighing is independent of the physical properties of the material — it requires no knowledge of density, dielectric constant, or the speed of sound in the medium. Furthermore, it is unaffected by phenomena such as dusting, foaming, bridging, rat-holing, or caking. As a result, a vessel weighing system provides a direct measurement of mass — the quantity that is most relevant in production and accounting processes.

Can a vessel weighing system be fitted to an existing tank?

Yes — we design weighing kits for both newly constructed and existing tanks. Mounting plates are tailored to the shape of the tank feet, enabling quick installation without any structural modifications. Where modification of the tank supports is not possible, extensometers are available as an alternative — sensors fitted to existing load-bearing elements that measure mass without any structural changes.

What factors affect vessel weighing system accuracy?

The most common source of measurement errors in silo weighing systems is the presence of additional lateral forces acting on the vessel. These may arise from rigid pipework connections, ventilation ducts, access platforms, or other elements in contact with the tank. For this reason, it is essential to use flexible expansion joints on all connections and to select appropriate mounting assemblies with load transfer elements. Accuracy is also influenced by the accuracy class of the load cells, the quality of calibration, and the stability of the supporting structure.

How many load cells are required for a vessel?

The number of load cells corresponds to the number of vessel supports. The most commonly used configurations are 3 load cells (for three-legged vessels — a statically determinate arrangement, the simplest solution) or 4 load cells (for rectangular vessels or those with four supports). For large silos or vessels with six or eight legs, a correspondingly greater number of load cells is used. In each case, the rated capacity and accuracy class of the load cells are selected to suit the specific application.

What materials can be weighed in vessels?

Virtually any type of material. A vessel weighing system measures mass independently of the physical properties of the medium, making it equally suitable for bulk solids (powders, granulates, cement, grain, flour, animal feed), liquids (milk, chemical liquids, fuels, oils), and gases. Dusty, corrosive, foaming materials, or those with a variable density or low dielectric constant — none of these factors affect the accuracy of gravimetric measurement.