Circular chart recorder

Types of circular chart recorders

Uncircular chart recorders, also known as circular strip chart recorders, are devices that record and graph variable data, such as temperature and pressure, for visual understanding at a glance. They usually have a circular shape and can further be classified into subtypes based on their various data-logging mechanisms.

These chart recorders can be classified into:

• Mechanical or Passive-Circular-Chart Recorders): These devices were the traditional types of circular chart recorders. A bimetallic strip was employed to make temperature measurement; two strips of different metals were bonded together, which expanded differently when generating heat. The expanding strip of metal would deform and bend the bi-strip, moving a pointer that indicated temperature on the dial. In this system of operation, the machines that recorded data on circular charts operated merely on externally supplied mechanical force without the need of power.
• Electronic Circular Chart Recorders: Today's technological development has moved most of the charts into the electronic system of records. These circular chart recorders use electrical sensors to measure the data to be recorded, which is then displayed on a chart. They are considered more operational and beneficial than the circular mechanical chart recorders, mainly because the graphs are more accurate, can be read remotely, and more data points are recorded in less time. Temperature sensors, pressure transducers, and humidity sensors are common sensors used.
• Hydraulic Chart Recorders: These chart recorders are employed mostly in the oil and gas industries and use hydraulic fluid movement for the chart to rotate and record fluctuations in pressure and temperature. Operation :Hydraulic-pressure chart recorders measure temperature and pressure through fluctuations in hydraulic pressures.

• Pen or Inkless Chart Recorders: These chart recorders may be pen or inkless, depending on the technology. For the pen chart recorders, the recorder of the chart would use a pen to record lines on the chart. In the case of inkless recorders, temperature changes were shown by restoring the circular chart without ink but rather through a soft, delicate carbon cylinder on the reverse chart that would include carbon paper and provided an effortless neat line without an accident or ink mess.

Industrial applications of circular chart recorders

• Subsea Engineering: Calibration is critical in the subsea engineering process and design. Circular chart recorders come in handy in temperature and pressure monitoring at reservoirs' extraction and pipeline transportation stages, helping to enhance the safety of the entire processes.
• The Oil and Gas Industry: Offshore drilling and production operations within the oil and gas industry are subject to stringent regulations. Chart recorders play an important role during compliance monitoring, ensuring that operations continuously fall within approved environmental and safety thresholds.
• Marine Construction and Repair: Circular chart recorders are used in temperature and pressure gauges to measure heat and pressure in construction and repair activities on vessels and marine structures such as oil rigs and pipelines.
• Navy and Maritime Operations: Applied to measure temperature and pressure in critical systems such as propulsion, engines, and equipment aboard naval vessels and submarines, chart recorders enhance their reliability and peak performance.
• Environmental Monitoring: Offsets caused by circular chart recorders in both land and sea environments help track temperature and pressure changes to predict conditions that could cause future dangers such as oil spills and other hazards.

Factors influencing the selection of circular chart recorders

The following factors should be considered when selecting a circular chart recorder for a particular task:

• What parameters need to be recorded: The first step in selecting a circular chart recorder is stating what should be monitored. Circular chart recorders can be used to monitor temperature, pressure, humidity, flow rate, and concentration chart of some variables. Pressure chart recorders are best for reliable pressure monitoring.
• Accuracy: Accuracy is a critical factor in measurement and data logging. The selected recorder should maintain the accuracy level required for the specific application. Accuracy is commonly measured in terms of percentage full-scale range, i.e., X% of the total recorded range. In some instances, high accuracy is nonessential, but in others, the error could damage products or equipment or cause danger to personnel.
• Environmental Factors: These are conditions such as temperature extremes, humidity, dust, and exposure to chemicals that can affect the performance of the recorder. The following recording devices may be adapted to hostile or even extreme environments by using protective housings and appropriate sealing. For outdoor applications, it is also advisable to use weatherproof housings for the devices to be placed outdoor.
• Chart Duration: Different circular chart recorders are capable of recording for different durations. Some recorders might record for some hours and others some days, depending on the application requirements. If need be, select a recorder with a longer duration if the data operation is continuous and requires frequent monitoring.
• Data Retrieval and Analysis: Data on circular chart recorders can be collected electronically, thus making ease of data retrieval. Some accept wireless and other remote collection systems for faster analysis of the data to be monitored. If such options are required for fast compliance, select a recorder that uses 'wires' and facilitates 'quick' retrieval of the data for analysis.

Maintenance tips for circular chart recorders

Proper maintenance ensures an uninterrupted service operation, high accuracy in the readings and records, and a long life for circular chart recorders.

• The circular chart used in recording instruments, and equipment should be cleaned often to avoid the wear and tear of the equipment and long life and efficiency of the instrument. Cleaning the recorder may also give one the wrong results by dust and other foreign materials on the device or the charts. Some of the parts needing routine cleaning are pens, plotters, and other parts of the machine likely covered by charts.
• The charts should be changed according to the specifications given by the manufacturer. Overuse of a chart can make it difficult to read the data recorded and, in the longer run, can affect the device. The significance of using genuine charts from manufacturers is that they are designed to fit and work well with the device.
• Calibration is essential to maintain the accuracy of circular chart recorders. Periodic calibration against known standards ensures that the recorder provides accurate readings. Calibration intervals may vary based on regulatory requirements, usage intensity, and the application’s critical nature.
• There can be no less important humidity and temperature circular chart recorders than the others that should be placed and secured in their positions and any stress removed from the cables connected to the device. Cables and connectors need regular inspection to avoid breakdowns in communication. The movement of hardware can lead to its damage, and tightening it up can limit this damage.
• To increase the working life of rotating parts, lubricate them often as required by the manufacturer.

Q and A

Q. How does a mechanical circular chart recorder work?

A. Temperature or pressure was measured through physical movement to record variables on a circular chart in a mechanical circular chart recorder. Bimetallic strips expand and contract due to temperature change and pressure, moving a pointer that shows the result on the dial. For fluids, pressure and temperature in hydraulic recorders turned charts using fluid dynamics principles.

Q. What is the importance of the humidity and temperature circular chart recorder in agriculture?

A chart recorder is crucial for agriculture because it helps monitor the right variables for product storage for flowers, fruits, and vegetables and for the optimum growth of plants.

Q. What is the difference between a hydraulic and a mechanical circular chart recorder?

The most noticeable difference is that the mechanical used the mechanical movement and operation of the chart recorded system while the hydro used fluid movement as the operational principle of the chart that was recorded in both systems.

Q. What are some critical precautions that should be taken to maintain circular chart recorders?

A few simple steps can go a long way in extending the life of circular chart recorders. These include routine dusting of external dust from parts, properly changing charts, inter- and intra-chart chart calibration, an emphasis on the use of gaskets, inspection, and maintenance of internal components and connectors, and lubricating all moving mechanical parts regularly according to established manufacturer's guidelines.

Q. Can circular chart recorders be used outdoors?

Yes, but care must be taken to ensure they are weatherproof and can withstand environmental conditions such as sunlight, rain, and extreme temperatures.