Development in the use of hydraulic wedges for breaking casting risers and casting parts

For the breakage of casting attachments or for the separation of parts in a casting, technical tools known as wedge feeder breakers, or casting splitters, are used.
These tools have been developed thanks to over a decade of direct “field” experience.
The hydraulic wedge is a form of breaker that allows for use with minimal insertion space (from 5 to 10 mm) and is available in various types that can be used vertically or in all positions.
Most hydraulic wedges are characterised by lightness and compactness, making them suitable for use in small spaces where other breaking mechanisms would not be usable.

Vertical breaking wedges

Vertical breaking wedges are made with a particular structure that guarantees a perfectly linear lifting movement, preventing the load from overturning. These vertical hydraulic wedges are suitable for breaking objects with limited insertion space and can be used in various applications.

Wedges for breaking loads from a flat surface

These divaricator tools are specially designed to create a starting opening in tight spaces where other tools cannot access. Therefore, expansion wedges are suitable for multiple applications.

Wedges for flanges

Flange divaricator tools, on the other hand, are designed to separate flanges without causing damage to either the flange or the diffusion arm. They are particularly useful for maintenance work.
Moreover, multiple divaricator wedges can be used side by side to better distribute the force.

Transition from dual-pump control unit to single-pump control unit

The goal during the design of demolition equipment has been to maximise the breaking power with the minimum amount of energy used. To achieve high pressure (about 320-350 bar), a small-size cylinder-wedge group has been used, which is lighter and more manageable. This has been applied to a hydraulic unit with a single motor and two pumps, one at low pressure with a high flow rate and one at high pressure with a lower flow rate. This way, it has been possible to reach a pressure of 350 bar (max 400) with a 2, 3, or 4 kW motor depending on the equipment model.

However, this solution caused a slower movement of the demolition equipment due to the high power during breaking, which slows down the movement, especially when the second pump comes into operation. Initially, it was thought that foundries were more concerned about reducing energy consumption, considering the speed acceptable.

Nevertheless, it later emerged that production needs a higher speed. Therefore, it was decided to introduce a new series of wedge demolition equipment with a single pump to make the breaking movement faster. To maintain the great breaking power and reach 320 bar of pressure, a 9.2, 11, or 15 kW motor has been used depending on the model, which allows achieving a suitable speed for the new needs.

This series, called SMAT, includes models of various sizes:

• The SMAT 50, 63, 80, and 100 models are equipped with a swivel head that simplifies the insertion position of the wedge and are operated using two hands. They are suitable for breaking all types of moulds and castings of various sizes
• The SMAT 50 MINI model, on the other hand, has a fixed head, is manoeuvrable and fast, and is useful when the space between the piece and the mould is limited. It can be used with one hand

All wedge breaking tools offer numerous advantages:

• Reduced costs thanks to the speed of the operation
• Minimal investment
• Elimination of noise
• Dust and possible accidents related to traditional systems using cutting wheels or hammers
• Minimal space requirement
• Simple installation
• Ease of use

The benefits of installing wedge smasher with its own hydraulic power unit

These tools have been extensively tested in various production settings and are capable of removing risers and castings, or breaking down channel risers into smaller pieces, for both gray and ductile iron as well as manganese steel castings.

Standard models are distinguished by the use of an independent hydraulic power unit.
In the past, technicians have often created multiple hydraulic power units to apply the different cylinder groups. The location of such power units has been determined based on an analysis of the advantages and disadvantages compared to the installation of the standard system, which provides an independent power unit for each wedge smasher group.
However, it is possible to construct a multiple hydraulic power unit to serve different wedge feeder breakers.

A “multiple hydraulic power unit” consists of a single pump that provides energy to 2-3 cylinder groups: attention must be paid to the flow rate that must provide sufficient speed to all groups.

However, if only one of the cylinders is used, the electrical energy consumption will be greater than that required to move a single group. Furthermore, if one of the components of the hydraulic power unit fails, such as the pump or motor, all wedge feeder breakers will be stopped.

Alternatively, the term “multiple hydraulic control units” can refer to a central unit with multiple pumps, which is considered a more cost-effective solution than the previous one.
However, it should be noted that this central unit is larger and requires some space.
Additionally, the wedges will not work closely together but usually at a certain distance, which implies the need for longer iron pipes, constructed on-site. In this case, the oil present in the cylinder is never changed but rather always recirculated, without cooling or filtering. Moreover, it is not true that this solution saves space, as a pump and motor still require adequate space for maintenance, similar to a central unit with a single pump and motor, and everything is only multiplied by 2, 3, or 4.
Finally, in this case, the maintenance of any component of the central unit (such as the pump, filter, tank, or electrical part) requires the shutdown of all the wedge feeder breaker groups, whereas in the standard solution proposed here, only one material handling group is stopped at a time.
As for the cost, the multiple hydraulic control units require a larger and sturdier oil tank, and the cost of components such as pumps, motors, valves, and others remains unchanged, as each cylinder group requires such dedicated components; therefore, the price is not more cost-effective than the various independent central units.

The same issue arises for the electrical control part: despite using a single electrical cabinet with a single lockable switch, the controls are separate and independent for each pump and cylinder.

In conclusion, the company believes that the marginal savings resulting from the use of a single electrical cabinet do not make the adoption of a multiple hydraulic control unit advantageous, especially considering the potential damage caused by the need to stop all groups in case of maintenance.
According to the technicians, the only disadvantage in installing several independent central units concerns the need for electrical power with multiple cables and separate panels, but this can be easily overcome by using a larger cable and connections in a box near the various groups. If the groups work at greater distances, it is more practical to pull an electrical cable to the position of the central unit rather than bring the hydraulic pipes of a multiple central unit to different points, with all the disadvantages this entails. Additionally, with independent hydraulic central units, it is possible to easily move a group where necessary.

Another important aspect concerns the maintenance and revision of the hydraulic control units of the wedge feeder breakers, which can be performed by the seller thanks to their reduced size, avoiding the costs of transportation and a technician who needs to intervene on-site. Furthermore, the company usually has all the necessary spare parts for the maintenance, repair, and accurate revision of the independent hydraulic control units. This would be much more difficult with a multiple hydraulic control unit, especially considering the impact on production due to the shutdown of all the groups.

In summary, it is worth highlighting the benefits that make wedge feeder breakers with independent hydraulic control units the ideal choice:

• Use of energy proportional to the equipment’s needs
• Installation of the control unit near the wedge feeder breaker usage area, with less hydraulic oil travel and therefore better usage
• Convenience in case of the need to move a wedge feeder breaker to a new working area
• Possibility to perform maintenance on one group without stopping the other independent wedge feeder breakers
• Possibility to send the control unit for maintenance or revision instead of requiring an intervention at the foundry