Batching of polyurethane for mine applications

BATCHING OF POLYURETHANE FOR MINE APPLICATIONS

Typical use:

The Polyurethane Mine Foam is used to control mine ventilation by sealing air leaks in and around metal, wood and other areas which may need ventilation control. It can also be used to fill water leaks and provide sound and thermal insulation.

The task and requirement:

A customer wanted to batch 20 barrels of polyurethane from the mixer to a canister. They required a highly repeatable and high accuracy for the batching process. The medium has a high viscosity which can be a limitation for most other measuring principles.

Our solution:

For fluid measurement we are using a 1” IOG (Industrial Oval Gear) meter together with an ILR740 meter mounted output which connects to the PC200 batching display, which was used to control the batching process.

Devices supplied:

For fluid measurement: part code IND OG-1”-S-S-ILR740 -1-V

For the batching process: PC200

Additional parts that the customer used:

Screw pump

Bypass, filters

Pneumatic angle valve

Electric box with equipment

Additional START/STOP box hose

Facility description:

In the picture below, right, the whole system and batch application.

In the picture below, left, the filling nozzle and the START/STOP button control.

In the picture below, the 1” IOG meter with the ILR740. The screw pump is normally installed on the front (black wheel). A bypass valve is located on the left side of the oval gear meter. The tube coming out of this bypass has been connected to the tube coming from behind. This bypass is important to prevent a mechanical shock to the system during the shut-off of the valve. The accuracy is also improved by the bypass, as without the bypass, the fluid would run forward and then briefly backwards just after the valve has closed.

In the image below left, the panel mounted PC200, mounted in a control cabinet.

Process description:

The operator can input the batching value in the PC200 controller using the PC200 keypad.

The end of the hose is the put into a barrel and after that, the external button (START) can be pressed on the hose to start the batching process. The PC200 activates external relays for the valve and the pump. The customer is using external relays because of the high current which is higher than the internal PC200 relays are designed for. The fluid starts to flow and the flow meters begin to count. After reaching the pre-programmed quantity, the PC200 automatically closes the valve and turns off the pump. The operator can then change the barrel and start the process again.

A nice feature of the PC200 is the self-learning algorithm. It allows the shut-off time for the valve and the pump based on the correct amount of fluid flow. The mechanical parts such as the valve and pump are inert systems which the PC200 has to compensate for. In this case the PC200 has to send out the shutoff signal before reaching the right amount so that at the end the correctly dispensed amount is reached.

The customer can stop the batching process at anytime by pressing the “STOP” button on the hose.

Accuracy:
An accuracy of +-0,1 kg can be achieved when batching a 20 kg barrel.