Paper chart recorder

Types of paper chart recorders

A paper chart recorder is a device used to record measurements over time. There are two key types of paper chart recorders: strip chart recorders and circular chart recorders. Each type comes in different sizes and models to suit various applications.

• Strip chart recorder

A strip chart recorder uses a moving strip of paper to continuously record data. The strip is drawn past a pen or stylus that moves in response to the input being measured. This causes the pen to make marks or lines on the paper that represent the changing measurements over time. Strip chart recorders are commonly used in applications that require real-time monitoring and analysis, such as in manufacturing plants, laboratories, and weather stations.

• Circular chart recorder

A circular chart recorder uses a rotating drum or disc covered with circular chart paper to record data. As the drum rotates, a pen or stylus moves along the chart paper, creating a continuous line that shows the trend of the measured variable. The chart paper is preprinted with concentric circles that divide the chart into time intervals. Circular chart recorders are often used for long-term data logging and analysis in industries like energy, environmental monitoring, and food production. They provide a visual representation of how a parameter changes over time, making it easy to see trends and identify anomalies.

Specification and maintenance of paper chart recorders

• Specification

The specifications of a paper chart recorder vary depending on the model and intended application. Here are some of the main specifications.

• Chart Size and Duration

The chart size refers to the size of the circular or strip paper that the recorder uses. It is commonly measured in diameter or width and length. The chart duration shows the time period covered by one full rotation or scroll of the chart. It is usually expressed in hours or days. For instance, a paper chart recorder with a 6-inch circular chart may have a duration of 24 hours.

• Temperature Range and Accuracy

The temperature range of a paper chart recorder indicates the full span of temperatures it can record. It can be expressed in degrees Celsius (°C) or Fahrenheit (°F). The temperature accuracy of the recorder shows how closely its recorded values match the actual temperatures. It is specified in degrees and is commonly shown as the total error band, which indicates the total possible deviation from the true value.

• Chart Speed

The chart speed of a recorder denotes how quickly the recording medium moves. It is measured in distance per unit time and is usually given in inches per hour (in/h) or inches per minute (in/min). For example, a paper chart recorder with a 6-inch circular chart may have a chart speed of 1 inch per hour.

• Power Supply

It refers to the power source used to operate the recorder. The power supply of a paper chart recorder is usually shown in units of voltage (V) and current (A).For example, the power supply may be 12VDC.

• Pressure Range and Resolution

The pressure range of a paper chart recorder refers to the full span of pressures it can record, which is usually given in pounds per square inch (psi) or other pressure units. The pressure resolution shows the smallest pressure changes that the recorder can detect, and it is usually expressed in pressure units per chart graduation. For example, a paper chart recorder for 100 psi may have a resolution of 0.1 psi per chart graduation.

• Humidity Range and Resolution

The humidity range of the recorder indicates the full span of humidity levels it can record, which is commonly expressed in percentage (%). The humidity resolution shows the smallest humidity changes the recorder can detect. It is usually given in percentage points per chart graduation.

• Maintenance

Proper maintenance is crucial for the performance and longevity of paper chart recorders. Here are some essential maintenance tips.

• Regular calibration: It is important to periodically calibrate the recorder's sensors and pens. This ensures that the recorded data is accurate.
• Paper chart replacement: The recording paper should be replaced on a regular basis to ensure continuous operation. This prevents faded or damaged charts that compromise data quality.
• Clean the recorder: Dust and debris can accumulate on the recorder, affecting its performance. Therefore, it is important to clean the recorder regularly to sustain accurate recordings.

Scenarios of paper chart recorders

Due to the durability and reliability of the paper chart recorder, it has a wide range of application scenarios in various industries.

• Environmental monitoring

The paper chart recorder can record data, such as temperature and humidity, over time. Therefore, it is often used for environmental monitoring in situations that require strict control of environmental conditions, such as laboratories, food processing facilities, and pharmaceutical manufacturing plants. If there are any deviations from the desired parameters, paper chart recorders can provide hard data for analysis and compliance purposes.

• Quality control

In manufacturing processes, paper chart recorders can be used to monitor various parameters, such as pressure, flow, and temperature. They can ensure that the production process is within the desired range and meet the required standards. If any issues arise, the recorded charts provide tangible evidence during quality control investigations.

• Energy management

Paper chart recorders play an important role in monitoring energy consumption. They can track data such as electricity usage, gas flow, and steam pressure. Consequently, facilities managers can use them to optimize energy usage, identify inefficiencies, and reduce operational costs.

• Industrial automation

In industrial automation, paper chart recorders can be used to monitor and control processes. For example, they can track variables such as production speed, material flow, and equipment status, which can help with the optimization of production processes and ensure operational efficiency.

• Logistics and distribution

During the transportation of perishable goods, a paper chart recorder can be used to monitor the temperature and humidity of the goods. This ensures that they are stored and transported under the appropriate conditions to prevent spoilage and maintain quality.

Overall, in applications where continuous recording of data is required, paper chart recorders provide a stable, reliable, and easy-to-use solution for monitoring various parameters, ensuring compliance, and supporting quality improvement.

How to choose paper chart recorders

When selecting a paper chart recorder, there are some key features and specifications to consider.

• Temperature range:

It is important to ensure that the temperature range of the paper chart recorder covers the required temperature range of the application. If the temperature range of the application exceeds the ordinary range of the paper chart recorder, users can consider the one with an extended temperature range or choose other types of recorders that can meet the needs.

• Chart speed:

Choose a suitable chart speed to ensure that the recorder can provide sufficient resolution for the application. For example, higher chart speeds can provide more detailed information on rapid fluctuations in temperature and humidity, while lower chart speeds may be sufficient for applications with more stable environmental conditions.

• Chart size:

Choose the appropriate chart size based on the duration of data recording required for the application. Larger chart sizes may provide longer recording times, while smaller chart sizes offer higher resolution but shorter recording times.

• Power supply:

Choose a recorder that operates on the required power supply, such as batteries or external power sources, and ensure that the power supply can meet the application's needs for continuous operation and data recording.

• Communication interface:

Choose a recorder with an appropriate communication interface, such as RS-232, RS-485, or USB, to ensure compatibility with data acquisition systems or computer software for remote monitoring and data analysis.

• Accuracy and calibration:

Choose a recorder with the required accuracy and calibration capabilities to ensure the reliability and traceability of recorded data. Consider the recorder's calibration interval and the availability of calibration services to maintain its accuracy over time.

• Alarm function:

Choose a recorder with an alarm function to provide timely alerts when temperature or humidity exceeds preset limits, helping to prevent potential issues and ensure operational safety.

Q&A

Q1: What are the benefits of using a paper chart recorder?

A1: One of the benefits of using a paper chart recorder is its reliability. It is considered one of the most reliable methods of recording data. Paper chart recorders are also easy to use and do not require specialized training or knowledge to operate.

Q2: How long can the data on a paper chart recorder be stored?

A2: The length of time that the data on a paper chart recorder can be stored depends on the size of the chart and the recording interval. Typically, charts are designed to store data for a period of time ranging from a few days to several months.

Q3: Are there any alternatives to paper chart recorders?

A3: Yes, there are several alternatives to paper chart recorders. Some of the alternatives include digital chart recorders, computer-based data logging systems, and strip chart recorders.

Q4: Can a paper chart recorder be used in hazardous areas?

A4: Yes, it is possible to use a paper chart recorder in hazardous areas. However, it is important to ensure that the recorder is designed for use in hazardous areas and complies with relevant safety standards.

Q5: Can the chart of a paper chart recorder be replaced?

A5: Yes, the chart of a paper chart recorder can be replaced. Replacement charts are available in different sizes and formats to fit various recorders.