Gravimetric Control System

1. The Strong Points of Gravimetric Control System

(1) Shorten start-up time
(2) Saving raw materials
(3) Stabilize production process, improve product quality
(4) Reduce the ability and requirements for workers

2. The Function

The system is installed on an extruder to measure and calculate the weight per meter and extrusion output, and also make automatic control, which realize the constant meter weight and (or) extrusion output and make it running at set values.

3. The Applications

The production process control for plastics pipes, film, etc.

4. Precision Error

<0.3-0.5%(Differs from the different raw materials and machines)

5. The Parameters That Can be Set in GraviMac

(1) The output of extruder (Unit: kg/hr, Control the output by controlling RPM of extruder)
(2) Weight per meter (unit :kg/m; need linear speed input; Control the weight of per-meter by controlling the linear speed and extrusion speed)
(3) Statistical function (Statistics for the raw material and length consumption of duty shift)
(4) Out-of-tolerance alarm
(5) Control the status of input and output

Note: model and size are subject to change without notice.

GraviMac Display Control Module (Three Configurations of I, II and OEM )

Fully meet any requirements of production measurement for its easy operation and interface with abundant functions.

The Available Materials for GraviMac

1. Granular / The Pellet
2. The powdery (good flowability)
3. The fine powder (good flowing properties)
4. Mixture or Untreated material/Fine powder or Small spherical/powdery (good flowing properties)
5. Rubber (Granular)

Defects of Meter Weight & Gravimetric Control System

Meter Weight is the weight per meter of product. The dimension tolerance of product is stipulated by the relative ISO and national standards. As a result, the range of meter weight is limited. Mostly the constant meter weight is a parameter to just products qualified or unqualified.
Gravimetric control system keeps the meter weight of products constant within the range of set value via measurement and automatic control to extrusion line.

Defects of Traditional Extrusion Line without Gravimetric Control System

Traditional Extrusion Production System (Without the Meter Weight System):

(1) Usually, the meter weight of product during the startup process is uncertain, in order to meet the quality requirements, the workers have to adjust the production line for several times, which will cause lots of material waste and loss of time(the large size pipe is particularly obvious).
(2) The product thickness(like the pipe wall thickness)in the production process is affected by many uncertain factors, such as: unstable properties of material(like the add in of recycled material), melt index changes brought by material replacement, the stability o machine, immaturity of the workmanship, unsmooth discharging of material, even the grid voltage fluctuation .Finally, these factors are easily to lead the fluctuation of meter weight along with many potential quality risks occurred.

Advantages of GraviMac Series-Online Gravimetric Control System

When the extruder is switched on, in order to make qualified products with reasonable material in short time , it mainly depends on:
1.The experience, skill and luck of operators on production line.
2. Meter weight data can be obtained soon after startup :make the "unknown” empirical production become "known” precise production, so as to make valid and visible production adjustment.
3. Shorten startup time: once the products on line(e.g pipe)are connected with puller as normal,meter weight is automatically adjusted into the qualified range by Gravimetric Control System.The experience and skill of operator is not so important any longer.
4. Monitor the entire process: the product meter weight in the whole production process, and collect product meter weight in real-time, if deviations were found, it will immediately adjust the extruder or the puller to reach the stable meter weight and making it running according to the set value.
5. Product deviation alarm: product quality defect will be effectively prevented by the prompt reminder of quality risk alarm information.

Parameters Controlled to be Constant by Gravimetric Control System

1. Extruder throughput
2. Meter weight
3. Gravimetric Control System can simultaneously control the extrusion throughput and meter weight and keep them constant. It is usually used for the extruder with unstable extrusion throughput caused by various factors.

Product Configuration of Gravimetric Control System

Model Output Size
GMS-04up to 60350×310×620
GMS-06up to 200360×350×715
GMS-08up to 350395×372×810
GMS-12up to 450395×372×880
GMS-20up to 700530×468×920
GMS-30up to 900530×490×960
GMS-50up to 1200530×551×1080
GMS-80up to 1600530×582×1460