Advanced Liquid Control

ALC level control systems are totally Australian owned and designed. The home of ALC is Currumbin, on the Gold Coast, Queensland, Australia. Our facilities here provide for the manufacture, sales and on on going development of this product. The ALC story thus far is probably very similar to many products but none the less interesting. The original idea that heralded the start of this products design came about through the proprietor of a local pump shop. Years of experience in the pump industry observing time and time again the shortfalls of different facets of the equipment's and processes necessary to move liquids from one place to another spawned the desire to investigate the possibility of "doing things differently". So the first criteria that this new system should embody will be that the end product will provide enhancements in the areas where the current popular methods have weaknesses, or lack current technologies. From a consumer point of view, not a bad starting point, you'd have to agree!!

The Beginning

So it was after some lengthy discussion and brain storming between the proprietor and myself that we decided on the criteria that the prototype design was to encompass and they are listed below.

  • The control system had to be electronic and provide for:
    • Modular main system components.
    • Display liquid level.
    • Alarms for High and Low level.
    • "Pump run" status information.
    • Easy adjustment of switching and alarm levels.
    • Cost of the equipment to be affordable.
  • The level sensing system had to provide for:
    • Display of the liquid level.
    • Easy installation.
    • Greater long term reliability in the harsh pit environments.
    • Non corrosive materials.
    • Cost of the equipment to be minimal.

The prototype (Version 1.0) was manufactured and we assembled a test bed to put it through its paces. The top tank gravity feeds the lower tank at a rate determined by a flow valve. When the lower tank reaches the set start point it activates one of the pumps and water is pumped back into the top tank until the set stop level is reached. This cycle took about 3.5 minutes at full open flow and went 24 hours a day.

This rate meant that the system was doing about 400 starts a day. Our test tank pumps are (and remarkably still are) 800 watt and 1100 watt submersible models. The original design presented a couple of problems to correct in the control and power supply section (design oversights) and after modification it faithfully operated this test setup. My own interests centred around how well the main pump power delivery circuits handled the load as this area is the one subjected to the highest demands and therefore its ability or inability to cope would determine if the prototype design was as successful as first indications suggested. The prototype was installed at the beginning of February '97 and after 400 starts a day every day when June rolled around and the failure rate was still zero I was convinced that our original designs were worthy. In real application our best estimates are that the average pump set endures 3000 starts a year. 400 starts a day for 5 months represented about 20 years of operation without failure !!  After 72000 starts or 24 years of service using the estimates just outlined, our system finally failed. One of the 16 amp power relays failed. Replacement of this component is a pull out plug in operation. System integrity was restored in a matter of seconds.

The Next Step

The finishing touches to the printed circuit designs were done and they manufactured. Version 1.1 was born. At the end of July '97 the first V1.1 system was installed and it has been running trouble free since. This installation was a dual single phase pump set utilizing 1100 watt pumps. With all the spare time we now had because we no longer spent countless hours keeping a vigil over the test tank looking for problems I suppose it was inevitable that we would venture down the path of further product enhancement. It was decided that this product should also provide for the following facilities.

  • Over current protection for single phase pump motors.
  • Pump Fault monitoring.
  • Three phase pumps.
  • Remote Alarm monitoring facility.

To facilitate the over current protection for single phase pumps electronic current monitoring circuits were designed that allowed the trip point to be varied from 2 to 35 amps. Fault indication and reset circuits were added to the design as well as an alarm output with volt free contact operation for remote monitoring of alarm status. Careful and deliberate printed circuit board design techniques were used during the rehash of the main power board to incorporate control of three phase or single phase pumps using the same power board. The enhancements heralded Version 1.2 and like its predecessor, was committed to the extraordinary task of running the test tank. The first Version 1.2 systems were installed in September 97 and have operated trouble free from that time. A small design change to the Version 1.2 power board saw Version 1.3 in this period.

The Product Refinement Phase

As with all designs, what may have first appeared to be the best way to achieve an end invariably, with hind sight, is not. Systems built to this time were comprised of four boards. A power board, control board, display board and a sensor board. We assessed that assembly and installation procedures would be refined and made easier if the sensor board electronics were combined with the power board. Version 1.4 created in July '98 incorporated this change and is the current build specification. Component design changes by component manufacturers necessitated creation of Version 1.5. Version 1.6 designs incorporated a tank empty or tank fill control option. With the exception of the Version 1.1,1.2 all system components are back wards compatible.

The Inevitable Processor Controlled Model

It is pertinent to mention at this point that the area's recognized by us as problems are not solely associated with equipment as such. It was clearly identified that some equipment failures could be prevented or pump damage minimized if better reporting mechanisms existed that alerted users to fault conditions and maintenance requirements. The modular design of the standard equipment allowed me the flexibility to now embark on a microprocessor based control board design that would be the same physical size as the standard control board and have identical input and output connections and thus become an option component for standard systems. The microprocessor based board was designed in August '98 and has been operating the test tanks without failure from that time to date. With the companion VPC software running on a standard PC, we could now remotely control and monitor all activity at the test tanks, as well as keep a log of all tank activity, thus achieving our objective of providing a reporting mechanism.

Liftwell and Level Indicator models

It became apparent along the way that these designs did not fully cover all areas of liquid monitoring and control. Some applications required less control options and so a single board controller was designed for systems that did not require dual pump operation, fault monitoring or start and stop point flexibility and so the Liftwell model Version 1.0 was born. Models of this type have been in operation since September '98.

A liquid level monitoring system was also designed to accommodate purposes that do not require control. This model can be optioned to provide remote monitoring using a Serial data link between the Monitor and PC running VPC software.

The Current

In 2001 ALC decided to take advantage of the competitive LCD prices. A new CP design utilized the LCD display thus enabling a much more verbose form of operational status to the user. This required a new front label design with a clear window for viewing the LCD. The new front label also incorporated bubble type tactile switch's that greatly reduced the risk of switch damage in transport. This model is still the current model on offer in 2009.

The Future

Component supply and design changes will necessitate the redesign of circuits and circuit boards to stay with current technologies. ALC is committed to product enhancement and the ongoing development of new products.