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Quality and Research, RDI


STEMM works on technologically advanced projects in an aim to meet the many needs of its clientele spanning different industrial sectors. Having performed the pertinent tests, in line with quality assurance and feasibility standards, we incorporate our innovative solutions as standard into our grapples and clamshell grabs.

The many recent innovations developed by our engineering and R&D services include:



Our grapples for waste and clamshell grabs for cement and clinker come with an auto-filtration system called a ‘KIDNEY’, which is always fully incorporated into the machine itself. This instrument, patented by our engineers, requires no maintenance and self-cleans automatically, requiring no operator intervention.

The KIDNEY works whenever the motor is running and automatically performs continuous MICROFILTRATION AT 3 MICRONS CLASS NAS-6, ISO 17-15-12.

This full and systematic auto-filtration ensures the hydraulic circuit remains extremely clean, thereby guaranteeing no breakdowns or incidents.

Furthermore, the bases of STEMM tanks are fully magnetised to attract and catch any metal particles.

Thanks to our new AUTO-FILTRATION system, our machinery also achieves oil-performance levels of over 4,000 running hours.


All the pumps installed in our machinery are state of the art. Their bodies are die cast and they are designed to work in conditions of extreme pressure (315 bars).

innovacion BOMBA DOC9

They are hydrostatically balanced and have automatic side alignment features. They comply with all American regulations related to excavators and Mining and Public Works machinery.

They are very quiet, not reaching 60 decibels, which is an essential feature for compliance with the evermore demanding regulations for industrial facilities, such as: incineration plants, biomass treatment plants and all facilities related to the environment.

Their shafts are splined to withstand the harsh conditions under which these machines work, as well as the high starting torque that is so common.

Guarantee of 3 years at 16,000 running hours in normal conditions.

The elastic couplings used to connect the electric motor to the pump are made of STEEL+NYLON, guaranteeing maximum transmission.


The speed of handling achieved thanks to this system is unmatched by any other system of method; a quality that is particularly appreciated in the iron and steel industry.

The speed is adjusted automatically depending on density, humidity, granulometry and, more specifically, the degree of compactness of the product to be handled.

This system is combined with the double-venting (electric and hydraulic) system, providing surprising results as regards power regeneration. It achieves a 50% increase in work cycles and, therefore, a reduction in daily electricity costs. Both systems work automatically and simultaneously, but they are independent, creating a perfect combination of hydraulic and electric power.

The double venting resets itself after each complete opening and closing manoeuvre, working like an automatic hydraulic pressure switch, always preventing oil lamination and ensuring there is never any heat in the circuit.


The grapples and clamshell grabs can work in any position, even horizontally, at 90º without creating any problems for the pump suction.

innovacion 4 INCLINACION DOC14

The tanks are watertight and pressurised at 0.3 bars, which helps the pumps work and ensures there is no cavitation in any inclined position.

Furthermore, as an additional safety measure, the machinery is supplied with built-in inclinometers in the electrical panel. These digital or analogical inclinometers are omnidirectional and work in any position (360º), providing a double signal.



All the claw and valve joints are STEEL-STEEL, with shafts that have been hardened, tempered and ground using the very latest manganese phosphate surface treatment.

The casings are also hardened and tempered to 65 Hrc with watertight decompression grooves that completely protect the joint, preventing the lubricant leaking out and any dust or particles getting in. 

No maintenance or lubrication of our joints is ever required.


When you place an order with STEMM, our sales service will issue a document accepting the order and give you a password. You can then access our servers via your computer, tablet or smartphone and take any virtual tours you like.


This service allows you to monitor your order and keep informed of the current status of the manufacture and supply of each of its components.

The photos, diagrams and videos are updated daily. This service is available 24 hours a day until 15 days after the machine has been shipped.

innovacion 6 AUTOMATA DOC3


Once the equipment has been manufactured, it is tested uninterruptedly for 48 hours by connecting it to a programmable logic controller (PLC) that simulates real operation.

Once the PROVISIONAL ACCEPTANCE testing has been performed, you are given the opportunity to watch a 4-5 minute video showing the parameters and results obtained, with the opening and closure times, consumption, pressure, and temperatures obtained during the tests.

You can also see the detectors, correct closure control, the condition of the lips, teeth, joints, synchronism, opening and closure mechanisms, as well as an overall view from several different angles. Thanks to this service, there will be no need for you to travel to observe routine tests on standard mass-produced machines.


The hydraulic circuits in our machines are fully integrated into a MANIFOLD BLOCK, which is the heart of the machine. They are standard, interchangeable pieces of equipment for all machines.

innovacion7 BLOQUES DOC18

All the valves and components are composed of LOGIC COMPONENTS IN CARTRIDGES inserted into the block. They are completely impervious to any impurities that may exist in the circuit, which affords the system a very long life (with no filter change necessary).

Moreover, these MANIFOLD BLOCKS are incorporated into a DECOMPRESSION SYSTEM that prevents the much-feared fluid hammer that is so damaging to hydraulic facilities and the structure itself. There is also no possibility of leaks. This block dismantling system makes maintenance work much easier.

All the blocks are kept in stock and are tested in 8-hour processes over 10 days with 40 cycles per hour.


STEMM has developed a very modern synchronisation system for the valves in the clamshells. It ensures perfect, exact, uniform opening and closing movements at the same time in both clamshells.

This simultaneous synchronisation is not possible with traditional valve synchronisation systems, which consist of two bars on each side of the clamshell buckets. STEMM has developed a system with perfect hydraulic synchronisation using flow dividers and flow control valves that compensate for pressure and temperature.

The movement achieved is smooth and regular, allowing identical variations in speed, cadence and positioning in each valve. This allows us to achieve surprising results as regards dose and controlled feed for the pharmaceutical, petrochemical, glass and ceramics industries.


innovacion9 KIT DOC20The system allows them to be fully programmed using the logic controller on the gantry crane or remotely operated using the remote control service GRAB CONNECT which is always included with STEMM equipment installations.

For applications where a grapple or clamshell grab will be working in a completely automated process.  STEMM developed KIT 2012-A comprising electrical, electronic and hydraulic components, which is essential for an optimum and safe configuration of any automated process working non-stop at full capacity.

KIT 2012-A comprises a series of components that emit, reflect or register peripheral, informative, determining or selective signals, indicating the level of performance of the main and vital components in the machine.

This KIT should be synchronised and fully integrated with the crane PLC that should always control the whole system and will act in accordance to its programming and based on the information it receives from the grapple or grab.

Please do not hesitate to contact us if you would like more information about this device. 


La función SCRATCHING es una función desarrollada para nuestros pulpos o cucharas para cuando trabajan en procesos totalmente automáticos, especialmente en las instalaciones de regeneración y manipulación de biomasa. Gracias a este dispositivo el pulpo o la cuchara trabaja de una forma inteligente, automáticamente sin intervención del operario.

Normalmente está prevista para trabajar combinada con el KIT 2012-A o bien ser regulada o programada a distancia gracias al control remoto GRAB CONNECT.


All STEMM equipment bears several stickers with QR codes that provide access to our YouTube channel where there are videos showing how to perform routine assembly and dismantling operations for all the machine’s elements and components, including joints, shafts, cylinders, pumps, valves, filters, etc. These videos also show you how to correctly perform monitoring and inspection activities as well as how to deal with certain incidents.

This is a service that is highly valued by our customers and which ensures their plant personnel receive continuous training, thereby lengthening the life of the machine by ensuring it is used sensibly and correctly.


Our remote control service GRAB CONNECT allows you to remotely diagnose, check and control a machine; programming and adjusting it in real time.

This service is an ideal tool for performing preventive maintenance and control operations, including start-up, change of parameters, pressure, etc.

The system allows you to see all manual (operator), semi-automatic and fully automatic manufacturing processes on your computer or smartphone in real time. You will receive notifications of incidents, as well as alerts related to temperature, the condition of filters, oil levels, running hours, etc.

You will receive a series of reports related to performance, real time diagnosis, technical support and production monitoring.

This data ensures you can confidently plan maintenance activity and make fundamental decisions related to investment in preventive maintenance. With the implementation of remote monitoring and reports a selection of data and safety-related reports are sent by email or SMS as soon as the incident has occurred.