Common instrumentation in pharmaceutical industry

Modern pharma equipment is built on the mechatronic engineering design, where mechanical and electronic components work together in successful machine operation. Instrumentation is also a part of mechatronic design that provides necessary inputs for the mechanical part to operate towards its operation accurately.

Instrumentation monitors different process parameters essential for a given pharma operation. The value of these parameters is then used by the main controller or a programmable logic controller to perform various functionalities.

Accurate selection and working of instruments is crucial for a satisfactory process operation. Because instrumentation in machinery monitors the process and product being manufactured which was traditionally done by manual or humans, if the instrumentation becomes erratic, the monitoring will not perform accurately. The process will fail to deliver its results.

What is instrumentation?

Instrumentation is an electronic device or component that measures the physical variables such as temperature, pressure, and humidity, during a pharma process. These physical variables are involved in operating that particular equipment that must be measured accurately to apply accurate and calculated quantity.

Like other industries, there are two major configurations in which instrumentation is used - Direct measurement and Signal conversion.

In direct measurement, the instrumentation’s output is connected directly to the main controller or a PLC, i.e., without any module, circuit, or converter in between. In this case, the controller or a PLC directly converts the physical variable into a form readable by the controller or a PLC.

The instrumentation’s output is converted to different signal levels fed to a main controller or a PLC in signal configuration. Commonly, there are two signal levels used by instrumentation, which are 4 – 20mA and 0 -10V. In this configuration, 4mA or 0V represents the lowest value that particular instrumentation can measure, while 20mA or 10 V represents the highest value that instrumentation can measure.

An instrument generally has three parts: sensor, signal processing, and presentation.

Sensor

The sensor is an integral and critical element that reads physical variables and converts them into another form, typically in an electronic signal. The value and type of signal are different for every different instrument type. For example, a thermocouple element converts temperature into microvolt, whereas RTD temperature sensor converts temperature into resistance value.

Signal processing

It is used to process the converted signal in a form that can be readable by the interface module. Because, at the sensor level, it is common that the detected values are very small, unstable, cannot be utilized, and require conditioning to be able to use by higher level instruments, modules or controllers. The signal processing section applies various algorithms to make them readable for controllers or PLC.

Presentation

After conditioning, the instrument’s output is interfaced to the final part, through which the signal is connected to the desired instrument or device. Commonly known as a terminal connection, it is the point where an external device is interfaced to the instrument.

Importance of instrumentation system

In Pharma operations, instrumentation is important in many terms, some of which are described below.

Monitoring

Instrumentation is used to monitor the process being carried out. Because, without monitoring, a process cannot be safely and satisfactorily executed.

In the pharma industry, apart from machine operation, monitoring is also required for many purposes, such as enabling quality in the output product and on–time completion of the process. Contrary to this, if instrumentation is not appropriate enough, monitoring will not be performed accurately, and the resulting process will not operate.

Regulatory retirement

During an inspection by different regulatory and standardization bodies, they review different records to ensure production has been planned and executed according to the guidelines. Among these records it also includes process variables during product manufacturing.

Instrumentation helps to provide records of these process variables for regulatory bodies. By using appropriate instrumentation, it is also possible to provide electronic records that can be presented during the inspection.

Helps to detect problems with a process

Instrumentation helps to detect a problem or deviation within the process automatically, without involving humans. Process variables such as temperature and pressure are vital to the success of the Pharma manufacturing process, any deviation could lead to errors or faults in the product.

Instrumentation is greatly helpful in preventing deviation in process variables and alerts the personnel in case of deviation. It enables them to take corrective and remedial actions.

Helps to detect faults in equipment

Instrumentation is also helpful in detecting equipment faults by indicating them. Any unusual behavior of instrumentation can also represent an error or fault in the basic machine's working.

Safe machine operations

Instrumentation ensures safe mission operation and prevents accidents. Monitoring various physical and process variables keeps these values under limit and prevents them from exceeding the threshold value. This property protects machine from an accident such as explosion due to over-temperature or overpressure

Instrumentation in Pharma industry

In the Pharmaceutical industry, the instrumentation is used in broad application areas, some of which are mentioned below.

Level measurement

Level instrumentation measures the level in an enclosed container, such as vessels and reactors. In addition to level monitoring, level sensors are also used to ensure the correct mixing of constituents of a solution.

Some pharma machines that utilize level instrumentation include the following.

·        Storage tank to monitor the level of water or liquid inside it to prevent overflow and variation in level

·        Granulation section to monitor the level of powder or granules in product containers such as FBD and RMG

·        Packaging machine to maintain a level of pharma product in the hopper. It also monitors the cap level in the capping machine's hopper.

Pressure measurements

Pressure measurement in the pharma industry is divided into two main categories: absolute and differential pressure.

The absolute pressure is the actual pressure exerted by some physical variable, such as water or air, and represents the actual value of it. The absolute pressure is directly proportional to the amount present and applied by that parameter. Commonly, it is used in

·        Vessels indicate the pressure inside it exerted by any substance such as liquid or a gas

·        Piping network to indicate the pressure exerted by different fluids such as steam and compressed air flowing in them.

Differential pressure is the difference between pressures from one location to another. In Pharma industries, there is a difference between the critical area and the surrounding area.

Instrumentation for differential pressure consists of two tubes placed in two areas for which the differential is required. The controller calculates the difference between the pressure exerted by two tubes and displays them at the required controller.

Typical application of differential pressure includes the following

·        Sterilization tunnel to measure the difference in pressure between surrounding and heating area

·        Critical areas such as clean room and manufacturing areas

·        Filtration units to measure the difference in pressure between the infeed flow and outfeed flow

Temperature

Temperature is the most commonly used instrumentation in Pharma industry, and measures the temperature of the area, process or product. It is used to execute a process at specific temperature and prevent over temperature during manufacturing.

There are different types of instrumentation for temperature, but commonly there are two types used in process industries, including the pharmaceuticals - Thermocouple and RTD.

Temperature instrumentation is used in

·        Autoclave for sterilization at specific temperature value

·        Blister packaging machine to monitor and control the sealing process

·        In tanks, to measure temperature of liquids or solution inside it. Because some processes require high temperature for the chemical reaction and to form final product.

·        In piping networks to measure temperature of fluid flowing in the pipes that are generated and required at certain temperatures, such as steam, hot water and chilled water.

·        In validation activities, where the temperature sensors are used to validate temperature sensors installed in the process equipment

Flow

Instrumentation for flow are used to measure flow of various variables in pharma processing equipment. It is a device that measures the rate of flow of a fluid across a tube, pipe or conduit. The flow values are then used for number of applications such as monitoring and controlling fluid in

·        Filling operations to measure the flow of liquid or sterile product in containers

·        Controlling the flow of raw water utility in water treatment plants

·        Dosing chemicals for water treatment

·        Monitoring and controlling different utility systems in piping network across the pharma facility.

Conductivity

Conductivity in pharmaceutical industry are used to measure conductivity in a liquid or water sample. It is the ability of a liquid to contact electricity, and indicator of presence of certain chemicals and salts.

For measuring conductivity in a liquid, a sample is drawn and contained in a small container. Conductivity apparatus contains two electrodes which are dipped into the container containing sample.

When instrument is powered up and measurement is started, the electrical current flows between anode and cathode. The instrument measures the electrical current between two electrodes and displays on it.

Instrumentation for conductivity are commonly used in

·        Water treatment plants to measure conductivity of the purified water

·        Conductivity of liquid product in storage and manufacturing tanks

·        Conductivity of product during manufactured

About the Author

Muhammad Asim Niazi has a vast experience of about 11 years in a Pharmaceutical company. During his tenure he worked in their different departments and had been part of many initiatives within the company. He now uses his experience and skill to write interested content for audiences at PharmaSources.com.