classic | mobile


SA Instrumentation & Control Buyers' Guide

Technews Industry Guide - IIoT 2017

Technews Industry Guide - Maintenance, Reliability & Asset Optimisation


Schubert & Salzer boost efficiency at BMW
August 2014, Valves, Actuators & Pump Control

In low pressure die casting, e.g. light metal engine blocks, the casting machines are filled by pressurising the furnaces. This requires highly precise pressure control along defined pressure curves in order to be able to produce a high quality casting and, for example, to prevent the metal pillars from moving around in the mould. In each case, BMW replaced the pressure control previously used for this purpose in its Landshut light metal foundry with a single sliding gate valve from Schubert & Salzer Control Systems. The outstanding control quality and the rapid reactive ability of the sliding gate valves have allowed the pressure head curves to be followed in a precisely reproducible manner.

In addition, they offer the possibility of compensating for process influences when furnaces of different sizes are used.

In the low pressure die casting process, the casting furnace is pressurised so that the molten metal flows up a riser tube into the casting machines. To ensure that the complete shape of the part is filled uniformly, it is absolutely essential to have a controlled rise in pressure. The pressure profile is crucial for quality in the casting process.

Sensitively adjustable pressure control is needed in order to reproduce these pressure curves time after time. It not only prevents pressure fluctuations, but also facilitates different mould filling speeds to optimise the filling of castings with different cross sections. BMW has all-round know-how in this area and is achieving a high degree of success in working with precisely defined casting pressure curves for the different versions of the component parts. Previously, a so-called valve organ with 13 digitally actuated valves of different sizes had been used to follow the pressure curve. While this pressure control was precise, there was a problem in that it was not immediately evident when a valve failed. The critical issue here was that the pressure curve was no longer being followed according to the reference data and the operator was not in a position to detect this. Therefore, a valve failure of this type could only be picked up by defects in the finished casting.

Josef Gibis, who has worked at BMW for 25 years and is currently the person responsible in Landshut for process development and design in the area of light metal foundry work, could not rest with this constraint. He searched for a valve solution that offered more process reliability. This would have to:

* Display a high level of quality with a rapid control response.

* Detect faults itself and flag them immediately.

* Be low on maintenance.

* Offer a good price-performance relationship.

The company HISTA Elektroanlagenbau Neutraubling, charged with the job of upgrading the foundry operations and developing new software for the comprehensive control processes, proposed that the 8021 sliding gate valve from Schubert & Salzer Control Systems, used already in other facilities, should be used here.

Flow-related advantages and variable Kvs values

The sliding gate valve offers a simple opportunity to modify the valve operating characteristics, which is the Kvs values as a function of the valve opening, almost infinitely. This can be done simply and in almost any conceivable number of ways by an appropriate configuration of the shape of the slit in the sliding discs.

After just two short project discussions on site, Schubert & Salzer‘s specialists calculated a Kvs value of 1,7 for BMW‘s foundry in Landshut. However, since different sizes of furnaces ranging from 1000 to 2500 kg serve a casting facility interchangeably, making it imperative that any process effects would have to be compensated, the sliding gate valve was selected at a Kvs value of 5 on an equal characteristic. As a result, not only does the sliding gate valve make it possible to follow the pressure curves precisely but it also has sufficient capacity with a larger opening to react to leakages, yet still be able to meter to the finest degree possible.

Outstanding rangeability and excellent control quality

The very good response behaviour in particular of the sliding gate valve is crucial for the excellent control quality. Short positioning paths, low moving masses and small actuation forces are the most important parameters for short reaction times with optimal resolution of the stroke position. The sliding gate valve offers all of these features in one package.

The typical stroke between open and closed is a mere 6 to 9 mm.

Sliding gate valves are an economically very efficient solution for a multitude of applications. Since they are available in different materials and in combination with all conventional positioners, they can be used in virtually all industrial areas and applications. Sliding gate valves are manufactured:

* In sizes DN 15 to DN 250.

* For pressures up to PN 100.

* For media temperatures between -200 and 530°C.

Sliding gate valves involved in process technology

The sliding gate valve is actuated at BMW by Schubert & Salzer‘s 8049 digital positioner. This highly accurate, electronic control circuit system was developed for the exact positioning of control valves. Using the configuration software DeviceConfig V7, a vast range of possibilities are available in setting the parameters of the positioner, such as:

* Setpoint signal range.

* Custom characteristics for a valve

* Hysteresis control.

* Operating direction.

* Configuration of the alarm output.

* Critical values for the maintenance alarms.

By using this positioner, the sliding gate valves are connected directly to the foundry control system and they issue messages concerning maintenance and diagnostic data as well as faults.

After the successful completion of the trial phase with the sliding gate valve in controlling casting pressures, BMW issued an order for the upgrading of one casting unit at the beginning of 2012. “We are looking for a valve that will fulfil our highest control requirements, that can be used for all sizes of furnaces and, as a result, offers additional scope in compensating for process effects,” says Gibis. “We are amazed at the precision with which these sliding gate valves fulfil these difficult control tasks.”

In view of these experiences, BMW recently issued an order to convert the pressure head control for nine further light metal casting units to sliding gate valves.

For more information contact Rowan Blomquist, Macsteel Fluid Control, +27 (0)31 581 7803,,

Supplied By: Macsteel Fluid Control
Tel: +27 11 383 4000
Fax: 086 644 1320
Share via email     Share via LinkedIn   Print this page

Further reading:

  • Sliding gate valves in control at PVS
    May 2018, Macsteel Fluid Control, Valves, Actuators & Pump Control
    Belgium-based PVS Chemicals produces extremely pure chemicals for use in the semiconductor industry. One of the company’s outstanding innovations is the production of ultra-pure sulphuric acid. As the ...
  • Test unit for control valves
    May 2018, AT Technical Services & Supplies, Valves, Actuators & Pump Control
    Although plant designers tend to treat them as ‘necessary evils’, it is obvious that control valves play a key role in process quality and reliability. Extreme care must be taken to avoid costly premature ...
  • Optimised pump ­performance
    May 2018, SKF South Africa, Valves, Actuators & Pump Control
    Ignoring pumps is a risk because when these components break down, or run below optimum efficiency, the whole process suffers. Manufacturing and process companies are always under cost pressure, making ...
  • Sealed bearings eliminate common failures in triple offset valves
    April 2018, Valve & Automation, Valves, Actuators & Pump Control
    Bearing failures are among the highest root causes of failure in triple offset valves (TOV) for tight shutoff applications. This issue is directly attributed to the need to have metal bearings with very ...
  • Proportional regulators optimise the use of compressed air
    April 2018, ASCO, Valves, Actuators & Pump Control
    Precise and reliable dosage of compressed air is needed in the manufacture of container glass to ensure an optimal distribution of the molten glass within the mould. ASCO Numatics has developed a valve ...
  • Selecting valves for proportional control
    March 2018, ASCO, Valves, Actuators & Pump Control
    When choosing the right valve for the job, it is important to understand the demands of the application and the relative merits of each valve type.
  • Should solenoid valves be classed as commodity items?
    February 2018, ASCO, Valves, Actuators & Pump Control
    Engineers seeking operational longevity and high-quality performance should think beyond initial purchase price, as any other strategy is likely to cost far more in the long run.       The technology The ...
  • Schubert & Salzer expands GS4 series
    February 2018, Macsteel Fluid Control, Valves, Actuators & Pump Control
    Sliding gate valves now optimised for pressures up to 160 bar.
  • Simple and easy to use, yet smart enough to automate
    January 2018, Valve & Automation, Valves, Actuators & Pump Control
    The V&A iCon® valve positioner family combines simple calibration and easy operation with high-level integration capability.
  • Precise control with segment disc valves
    January 2018, Macsteel Fluid Control, Valves, Actuators & Pump Control
    Segment disc valves work on a very simple but effective principle. The central throttling elements – the segment discs that glide and seal against each other – are positioned in the valve body perpendicular ...
  • Valve partner to the food industry
    December 2017, Macsteel Fluid Control, Valves, Actuators & Pump Control
    When it comes to manufacturing or processing foodstuffs and drinks, having the right valve in the right place is essential if things are to run smoothly. Of course it is important to consider whether ...
  • Special valves for steam systems
    November 2017, Macsteel Fluid Control, Valves, Actuators & Pump Control
    Robust segment disc valves contribute to availability of industrial power plants.

Technews Publishing (Pty) Ltd
1st Floor, Stabilitas House
265 Kent Ave, Randburg, 2194
South Africa
Publications by Technews
Dataweek Electronics & Communications Technology
Electronic Buyers Guide (EBG)

Hi-Tech Security Solutions
Hi-Tech Security Business Directory

Motion Control in Southern Africa
Motion Control Buyers’ Guide (MCBG)

South African Instrumentation & Control
South African Instrumentation & Control Buyers’ Guide (IBG)
Terms & conditions of use, including privacy policy
PAIA Manual


    classic | mobile

Copyright © Technews Publishing (Pty) Ltd. All rights reserved.