Archive for June, 2009

different kinds of industrial scales

Monday, June 29th, 2009

A wide variety of different kinds of industrial scales are the type of instrument which is used to measure the weight. These include platform and floor scales for larger types of boxes and containers. Crane scales are used for loads that may be suspended. Drum scales are generally used for pails, smaller tanks, dewars and standard size drums. For smaller items, bench scales are more appropriate. Laboratory scales and precision scales are used for the most accurate measurements.

All of these different types of scales rely on the transducer device which converts a force into an electrical signal. This device is often called a load sensor, or load cell. Larger floor scales and platform scales often use four load cells in each scale, one in each corner of the platform. Smaller scales most often only include a single load cell. The electrical output from most standard load cells are very small, millivolt level signals. Higher quality industrial scales compensate the load cells for temperature, so that the output signal remains quite constant for a given load. The output is often buffered and then directed to an analog to digital converter for processing by the scale before being displayed for the user.

Load cells may be built in a wide variety of different shapes and sizes, depending on the type and size of scale. Most larger platform scales use beam load cells that measure a level of shear. Bench scales may use single point load cells that measure strain. In both cases, thin sections of metal are supported by larger metal frames. The entire device is designed to act as a spring element. Strain gages are adhered to the thin metal sections. These gages measure either shear or strain, and thereby determine the amount of the load on the load cell. Those load cells that are designed for large platform scales must have thicker bending elements and a larger support structure. That is also the case on the single point load cells.
 injection moulding machine


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Prodcut Name: single point load cell

Monday, June 22nd, 2009

Model PT1022 is a low profile off centre load cell designed for direct mounting in low cost

weighing platforms. Its small physical size, combined with high accuracy and anodized

aluminium construction, makes this low cost load cell ideally suited for retail, bench and counting scales where savings in parts and labour due to simpler scale construction

can be made.

The two additional sense wires feed back the voltage reaching the load cell. Complete

compensation of changes in lead resistance due to temperature change and/or cable extension, is achieved by feeding this voltage into the appropriate electronics.

3Kg to 35Kg.

0.02% total error.

IP66.

For 350 x 350mm platforms scales.

Can be repalced by PTs PT1000 and PTASP6 cells.

Prodcut Name: single point load cell

Model: LP7161
Rated Capacity: 50/100/150/200/250/300/500/750kg
Accuracy Class: C3
Non-Linearity: 0.02% of F.S.
Rated Output: 2.0 ± 0.2mV/V
Input Impedance: 400 ± 10Ω
Output impedance: 352 ± 3Ω
Operating temp: -30 ~ +70
Destructive load: 200%
Recommended V: 4~12V (DC/AC), Max. 15V
Cable: Exc+ (red), Exc-(black) 4-wire with screen Sig+ (green), Sig-(white)
Construction: Platform Size600×600 mmAluminum / Alloy Steel, IP65
Application for: Bench / Counting Scale, Check weighing


Model PT1250 is a low profile single point load cell designed for direct mounting of the weighing platform, or side cell applications.

The savings achieved by requiring fewer parts and labour costs, resulting from simpler scale construction, makes the PT1250 a costeffective load cell for use in counting, weighing, bench,

or floor scale products.

It is available with metric or imperial fixings. This high-accuracy load cell is approved to OIML R60, NTEP and other stringent approval standards.

Suitable for use in hazardous environments, these load cells can be provided with EEx ia approval

A special humidity-resistant protective coating assures long-term stability over the entire compensated temperature range.

The two additional “sense” wires, sample the bridge supply voltage at the load cell. Complete compensation of change in the lead wires resistance, due to temperature change and/or

cable extension, is achieved by feeding this voltage into appropriate electronics.

Capacities 50Kg to 1000Kg.

Total error: 0.02%.

C3 Grade.

IP65, IP67 also available.

6 wire cable with sense wires.


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single point load cells

Wednesday, June 17th, 2009

Located in China, Ningbo G-Shine electronic Co., Ltd is a manufacturer and supplier of advanced Load Cells, Force Sensors, Torque Sensors, Pressure Sensors, Signal Conditioners, Digital Displays and Portable Sensor Verification / Calibration Systems (VCal) Ningbo G-Shine electronic Co., Ltd has demonstrated steady growth and built a solid reputation as a “load cell and weighing scale manufactor in China and overseas markets
Although our expertise in load cells / weighing scale applies to many industries, our product line and custom manufacturing ability is focused in the following industries:
loads cells including low profile load cells, single point load cells, miniature load cells, beam load cells, load cell accessories, S type load cells and column load cells.

A Universal Testing Machine
A Universal Testing Machine otherwise known as a materials testing machine/ test frame is used to test the tensile and compressive properties of materials. Such machines generally have two columns but single column types are also available. Load cells and extensometers measure the key parameters of force and deformation as the sample is tested. These machines are widely used and would be found in any materials testing laboratory.
A typical testing system is comprised of a materials testing machine/test frame, control and analysis software, and critically, the test fixtures, accessories, parts and devices used to hold and support the test specimen. A typical testing system is comprised of a materials testing machine/test frame, control and analysis software, and critically, the test fixtures, accessories, parts and devices used to hold and support the test specimen.
A tension test is a destructive test in the sense that the specimen is finally broken or fractured into two pieces. to perform the tensile test , the universal testing machine should be capable of applying that load which is requird to break or fracture the material. the test piece or specimenof the material is generally a straight piece, uniform in the cross-section over the test lenghtand often with enlarged ends which can be held in the machine holders. however, the machine can hold the specimen without enlarged ends also. two fine marks are often madenear the end of uniform test sectionof the specimen and the distance between these points is termed as “gauge lenght”. The gauge length is that length which is under study or observation when the experiment on the specimen is performed.the gauge lenght of a specimen bears a constant standerdized ratio to the cross-sectional dimension for certain reasons. the specimen is placedin the machine between the holdersand any measuring device to record the change in length is fitted on to the specimen between the gauge points. if such a device, generally extensometer,i not fitted the machine itself can record the displacement between its cross heads on which the specimen is held.


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Single Point Load Cell

Friday, June 12th, 2009

There are several components needed to make a good quality weighing scale. In this article I talk about load cells and strain gauges, how they work and important points to consider.

The load cell is one of the most important components in a weighing scale, when coupled with a digital indicator it dictates how well the scale will perform. Many low cost scales use cheaper load cells, understanding the quality of a load cell can be difficult.

The main component of a load cell is a strain gauge. Strain gauges are made up of an insulated flexible backing which holds a metallic foil pattern. The gauge is attached to a load cell by adhesive. As the load cell is deflected (by adding weight), the foil deforms, causing its electrical resistance to change. This electrical change is interpreted as a weigh value on the digital display.

Strain gauges are susceptible to exterior factors such as moisture and temperature, lower cost load cells may not be as well protected against these elements causing the units to develop errors or fail sooner.

Load cells help determine the following characteristics of a weighing scale:

Linearity:

Load cells may feature hysteresis style errors shown in the graph, the desired results is a straight line at 45 degrees this is the linearity. The increasing and decreasing load applied is displayed in a linear fashion

Accuracy:

This is the area that covers the difference between a reference and the value displayed on the weighing terminal. High accuracy scales can display weight readings to high resolutions and stay close to the reference value, for example a high accuracy load cell may be able to display 10Kg as 10.0000Kg, a lesser load cell may only manage 10.0020kg, it may also fluctuate and not be stable.

Repeatability:

Repeatability is the measurement in variation taken by a loading a scale with the same weight under the same conditions. A scale may be said to be repeatable when it produces the same measurements accurately with a defined mass.

Eccentricity:

Single point load cells may perform differently when loads are applied in different places. A high quality load cell will be able to display off centre loads accurately where as a lower cost cell may struggle to give accurate results. For example results for sections 1/2/3/4 maybe the same on higher quality load cells, results for lower quality ones may vary from point to point.

Water Filters Domestic reverse osmosis system


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Digital scales are devices to measure weights

Monday, June 8th, 2009

Digital scales are devices to measure weights. These can weigh anything from light weighted to heavy bodies. The scales work on the principle of load cell technology in which load cells sense the weight of objects under certain conditions. The weight thus obtained is transferred into digital or electronic signals and gets displaced in digital formats.

Available in varying models, brands, sizes, and shapes, digital scales come with accessories such as batteries, calibration weights, scale pads, and trays. You are also given easy reference manuals with most scales. The scales vary in prices and quality..

The steel coil is supported and weighed by a saddle. There is rubber on the interface to protect the steel coil against damage. The weighing range is 6t, 10t, 20t, 30t. It has various functions like automatic weighing, coil material, number, width, and thickness input; data storage and printing; can be connected to the preceding PLC or controller. It has durable scale board and high stability. The size of the board can be customized. The design of our scale board makes it capable of resisting more powerful strike. It can be equipped with printer according to customer’s requirement. Steel coil scale is mainly used on steel coil packing and transporting line and processing line. Coil car transfer scale are full electronic NTEP platform sizes from 4′ * 6′ to 20′ * 10′. NTEP capacities from 20,000 lbs to 120,000 lbs. Load cell overload protection to 150%. Designed for 100% concentrated Load capacity (CLC).

Scales can be built with flat decks, V-decks, or with rails for coil transfer car weighing. Non-NTEP electromechanical designs are available. To protect the coils from rusting, they are provided with the uniform coating of special rust preventive oil. This also guards against atmospheric corrosion, and allows for a longer storage period. This oil can be easily removed in normal degreasing once your coils are delivered. Coil scales have extra strong platform structure, automatic replacement adjustable feet, and anti-shock proof. These have high precision load cell and indicator, and reliable working stability. Coil scales have various options like ramp, RS232, printer, and weighing software.

Iron Sand Casting, Precision CNC Machining


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