The Pneumatic Conveying System Engineering Essay

The Pneumatic Conveying System Engineering Essay

1.0 Introduction

This study will be in two parts, in portion one, a hazard appraisal will be carried on a pneumatic conveyance system for fire and detonation jeopardies in the procedure while in portion two a care agenda will be carried out on the whole works system, placing care processs which are critical to the safe operation of the works.

Health and safety statute law relevant to the hazard appraisal and care will be discussed.

Part 1 ( Risk Assessment )


This conveyance system conveys high speed substances endlessly where compressed air is readily available. The system is used for conveying Pharmaceutical pulverization pharmex at low denseness over a short medium distance. A pneumatic conveyance system may transport solids up to about 50mm size and the pulverization or solid must be dry, with no more than 20 % wet. Since pneumatic systems are wholly enclosed, merchandise taint, material loss and dust emanation are reduced or eliminated.

The tabular array below shows the explosibility belongingss of the pharmex in the pneumatic conveyance system.

Minimal ignition energy/mJ

Maximal Explosion pressure/bar a

Maximal Pressure rise saloon m s-1

Maximum explosible concentration/g/ M3






The grapevine and blow armored combat vehicle are force per unit area rated to above 15 barg.

The filter lodging and having vas are force per unit area rated to 0.3 barg.

2.1 Risk Assessment Process

Hazard: This is the likeliness that a badness will happen, it ‘s besides the merchandise of chance of a failure event occurring and the unsought effect.

Hazard = Probability of failure ten Undesired effect

Hazard: This is the potency of a substance, activity or procedure to do injury ( Hughes and Ferrett 2003 ) . Anything that is non decently handled could be term jeopardy.

2.2 HSE Approach to Risk Assessment

Hazard appraisal is merely a careful scrutiny of what could do injury to people in a workplace or environment, so that safeguards available will be weighed if adequate, or more work should be done to forestall injury ( 2010 ) .

Measuring the Hazard

Measure 1-Identifying the jeopardies: A thorough walk around and inquiring right inquiry will assist indicate out jeopardies which could present a serious danger to both people and equipments.

Measure 2- Consider individuals at hazard: Deciding who might be harm will assist place the best manner to pull off the hazard.

Measure 3- Measuring the hazard and make up one’s minding on safeguards: The intent of hazard appraisal is to cut down all residuary hazard to As Low As its Reasonably Practicable ( ALARP ) . Basic hazard appraisal ( placing the hazard ) , quantitative hazard appraisal, and qualitative hazard appraisal are used in measuring the hazard.

Quantitative hazard appraisal: Measures the hazard by associating the chance of the hazard happening to the possible badness of the result and so giving the hazard a numerical value. The likeliness depends on the control measures of the topographic point, while the badness depends on magnitude of jeopardy ( Hughes and Ferrett 2003 ) .

Likelihood of happening Likelihood degree

Harm is certain or close certain to happen high 3

Harm will frequently happen medium 2

Harm will seldom occur low 1

Badness of harm Severity degree

Death or major hurt major 3

3 twenty-four hours hurt or unwellness serious 2

All other injuries/illnesses slight 1

Hazard = Likelihood X Severity



Little 1

Serious 2

Major 3

Low 1

Low 1

Low 2

Medium 3

Medium 2

Low 2

Medium 4

High 6

High 3

Medium 3

High 6

High 9


6-9 is high hazard

3-4 is medium hazard

1-2 low hazard

Qualitative hazard appraisal: This is based on personal opinion and is usually defined as high, medium or low. This sort of appraisal is normally satisfactory since the definition whether high, medium or low determines the clip frame in which farther action is to be taken. High hazard state of affairss need to be addressed in yearss, medium hazard in hebdomads and low hazards in months ( Hughes and Ferrett 2003 ) .

Occupational hazard degree




Organizational hazard degree













L – Low hazard M – medium hazard H- high hazard

Measure 4- Record findings: A formal coverage process needs to be implemented and incorporated into the current hazard appraisal coverage processs. The important jeopardies and decisions need to be recorded for the appraisal to be suited and sufficient. It should besides include bing control steps and their effectivity.

Measure 5- Reviewing appraisal and revising if necessary: Hazards and its controls should be reviewed sporadically and implementing controls where appropriate in instance of alterations in conditions such as new machinery, reception of new chemicals.


In sing the fire trigon, ignition beginning, fuel and air will favor fire detonation. In the pneumatic conveyance system, the pharmaceutical pulverization is the fuel, air in the system is the oxidizer and the basic for safety will be the remotion of the ignition beginning. The ignition beginning can be inactive charges, flickers from parts in gesture, hot surfaces caused by pulverization gesture. There should be an extinguishing safeguard, such as mounting the Bicarbonate sodium carbonate pulverization on the filter lodging to understate the hazard if there is an detonation. Fire and detonation hazard should be assessed in order to understate the possibility of it happening by guaranting that the elements of the fire trigon are shielded from each other so that they do non come in contact.

3.1 Hazards associated with the Pneumatic Conveying System

Filter lodging and storage hopper

This has to be treated as on vas, the having vas has to be strong plenty to take the weight of pulverization fed to it. The filter lodging and the receiving vas are force per unit area rated at 0.3 barg and can non defy the maximal detonation force per unit area of 10 barg, so a suppression unit should be fitted with a differential force per unit area transducer which helps to control the detonation should it happen. The force per unit area transducer activates the fire asphyxiator in instance of force per unit area rise thereby spraying hydrogen carbonate sodium carbonate pulverization in the event of an detonation.

The pipe line

The traveling pulverization in the grapevine has a low possibility of lighting as there is n’t sufficient clip for a flicker to reassign energy to the traveling pulverization. The grapevine needs to be inspected for possible corrosion and obstruction that can help in possibility of fire or detonation occurring.

Blow armored combat vehicle

The blow armored combat vehicle is capable of defying the detonation. The maximal detonation force per unit area is 10 barg which is less than blow armored combat vehicle force per unit area.


An isolation valve is needed to halt blow back to the compressor in the event of an detonation. Blow back arrestors should be installed to halt the pulverization from being blown back. To extinguish the possibility of the compressor going an lighting beginning as a consequence of the engine been excessively hot, it needs to be installed in a separate room.

Nozzle bank

As the full end product of the compressor is non needed, the nozzle bank should be fitted to command the flow of air. It consists of series of critical flow openings which will merely let certain maximal flow of air. The nozzle bank necessitates the varying of air flow rate from no flow to a series of flow rates depending on unfastened valves.

Pull offing the Ignition Source

Mechanical ignition beginning: Tramp metal in the valves, hot bearings, motors, and severely lubricated equipment can give rise overheating which is a beginning of ignition. To understate the chance of the mechanical parts going an igniting beginning, proper lubrication should be done and blushing done to free of the metal in the grapevine.

Electrical ignition beginning: Motors, not insulated wires can bring forth flickers and circuit could overheat hence cause a flicker. Proper insularity and particular motors are required for usage in potentially flammable milieus.

Inactive ignition beginning: Due to the pulverization and air denseness derived function, adhesive forces due to friction going down the grapevine might do inactive charges possible of moving as an igniting beginning. As a redress, earth bonding of all the systems including the filter bag which should be metal backed so it can be earthed. Tramp metal which acts as stray music director therefore hive awaying charges should be removed by testing.

Thermal ignition beginning: Overheating of parts in gesture such as bearings, motors and belt could move as a beginning of ignition. To understate the likeliness of overheating, the room where the conveyance system is housed should be decently ventilated to let air circulation hence cut down temperatures.

Human ignition beginning: The country of the works must be designed as a no smoke zone to guarantee or cut down the opportunities of illuming unfastened fires which can move as a beginning of ignition and cause detonation. To forestall possible ignition beginnings that might be caused by carelessness and other human mistake factors, the works should be installed in an independent room and staff/operators to the full trained, made aware of possible hazards and safety processs therefore understating the hazard of fire or detonation.


Fig 1

3.2 Classifying Hazard Areas in Zones

Hazardous topographic points are classified in footings of zones on the footing of the frequence and continuity of the potentially explosive ambiance. This helps to find the controls needed on possible beginnings of ignition that may be present or can happen in that zone.

From the fig 1 the conventional diagram of the pneumatic conveyance system, dust and pulverizations are classified in zones as follows

Zone 20 – A topographic point in which an explosive ambiance in the signifier of a cloud of combustible dust in air is present continuously, or for long periods or often ( Ansell Ray 2010 ) .

The having vas is classified as ZONE 20: Explosion is high since air assorted with pulverization can do detonation if igniting beginning is present.

Conveying Pipeline is classified as ZONE 20: There is ever plenty pulverization inside the pipe and air assorted with the pulverization with the presence of an ignition beginning an detonation could happen.

The Blow Tank is classified as ZONE 20: Explosion is really likely if an igniting beginning is present since air is assorted with pulverization.

Zone 21 – A topographic point in which an explosive ambiance in the signifier of a cloud of combustible dust in air is likely to happen in normal operation on occasion ( Ansell Ray 2010 ) .

Powder feeding station and discharge country is classified as ZONE 21: Explosion is likely to happen in normal operation on occasion if an igniting beginning is present. Caution should be taken so that detonation does non happen in an event of lighting beginning such as human or mechanical constituents due to clash.

Zone 22 – A topographic point in which an explosive ambiance in the signifier of a cloud of combustible dust in air is non likely to happen in normal operation, but if it does occur, it will prevail for a short period merely ( Ansell Ray 2010 ) .

The room where the Pneumatic conveying systems occupies is classified as ZONE 22: If there is a mistake in the pneumatic conveyance system, the pulverization could come out into the research lab. Under normal conditions an detonation is non likely to happen in normal operation except in a circumstance where pulverization assorted with air in nowadays of an igniting beginning.

Air compressor/Drier is classified as ZONE 22: Explosion is non likely to happen in normal operation nevertheless if it does it will prevail merely for a short period. It can besides be classified as NO zone if the compressor is housed in a separate room from the conveyer system.

For an detonation to happen air, fuel ( pulverization ) and ignition beginning has to be present. To minimise the likeliness of an detonation, possible igniting beginnings have to be eliminated. Some of these beginnings include Flickers due to clash, trapped metal filings inside the grapevine, smoke, electrical flickers, inactive charges etc. Therefore, to reason the undermentioned appraisal is done to be able to measure the hazards and sketch control steps:

3.3 Risk Assessment

Hazard at the works


Control steps

Hazard evaluation

Mechanical ignition beginnings: clash, metal filling, hobos

Fire and Explosion

Partss in gesture demands to be lubricated to understate clash and flushing of system

Highly Severe and medium likely

Electrical: short circuit and electrical flickers

Fire and Explosion

Use of proper insulating stuffs and lodging

Highly terrible and extremely likely

Thermal: overheating, high temperature

Fire and Explosion

Compressor housed in a separate room, proper airing to guarantee air circulation

Highly terrible and medium likely

Human factors: Smoke and hot working

Fire and Explosion

No smoke mark displayed every bit good as presence of fire snuff outing equipment.

Highly terrible and extremely likely

Factors such as leaking grapevine and weak receiving vas

Fire and Explosion

Use of suppression and fire snuff outing units

Highly terrible and medium likely


There are many statute laws but three are closely relevant to the hazard appraisal for fire and detonation. They include Health and Safety at work Act 1974 ( HASAWA ) , Dangerous substance and Explosive Atmosphere Regulation 2002 ( DSEAR ) and the Management of Health and Safety at Work Regulations 1999 ( MHSWR )

Health and Safety at Work Act 1974

This is footing of British wellness and safety jurisprudence. The act sets out the general responsibilities which employers have towards employees and members of the populace, and employees have to themselves and to each other. The responsibilities are qualified in the Act by the rule of ‘ so far as is moderately operable ‘ where employers have to take step to avoid or cut down hazard if they are technically impossible or if the clip, problem or cost of the steps would be grossly disproportional to the hazard ( 2010 )

The Management of Health and safety at Work Regulation 1999

The chief demand on employers is to transport out hazard appraisal. The Acts of the Apostless states that ‘every employer shall do a suited and sufficient appraisal of the hazard to the wellness and safety of his employees to which they are exposed whilst they are at work and the hazard to the wellness and safety of individual non in his employment originating out or in connexion with the behavior by him or his project ‘ ( 2010 ) .

The Dangerous Substances and Explosive Atmospheres Regulations 2002

Dangerous substance are any substance used or present at work that could, if non decently controlled, cause injury to people as a consequence of fire or detonation. The ordinance requires employers to command the hazards to safety from fire and detonations.

The ordinance requires employers to

Find out what unsafe substance are in the workplace and what are the fire and detonation hazard.

Put control steps in topographic point to take the hazard or command them.

Prepare programs and processs to cover with accidents and exigencies.

Make certain employees are decently informed and trained.

Identify and sort countries of the workplace where explosive ambiance may happen.

Part 2 ( Maintenance )

5.0 Care

Care comprises of any actions other than everyday services during operation that alters a merchandise or system in such a manner to maintain the system in an operational status if in a failed province ( John Moubray 1994 ) . Factors such as design, ageing, quality control, industry and use can take to the failure of a merchandise or the likeliness of happening of failure.

5.1 Types of Care

There are two chief types of care actions: preventative care and disciplinary care.

Preventive care is type of care that by and large requires closure of an operational system and are intended to increase the life-time or its dependability ( Babakalli Alkali 2009 ) .

Corrective care is type of care that comprises of actions taken to reconstruct a failed merchandise or system to an operational province.

Preventive care could either be condition-based or predetermined. Condition based care will be used to schedule care for the pneumatic conveyance system. Condition based care involves preventative care initiated as a consequence of cognition of the status of an point from everyday or uninterrupted monitoring ( Babakalli Alkali 2009 ) .


A license to work system should be got before the care work commences. The care must be carried out with the works shut down and all merchandises removed.

The Valves: They require periodic removal scrutiny and fix where necessary. The valves can be examined utilizing ocular review by the usage of optical/computer based aid or unaided oculus. In footings of fix, maker ‘s specifications should be followed for maximal wear of parts.

The conveying pipe: Supersonic testing could be used to find mistakes or anomalousnesss in shrieking tubings by conveying supersonic pulsations or moving ridges through the stuff and measuring the end point. The pipe requires periodic scrutiny and cheques for clefts and corrosion.

Compressor: All constituents in the compressor should be maintained in conformity with the maker specifications, filters and fluids replaced when faulty, leaks should be checked and belts adjusted where necessary.

The Blow Tank: This is a force per unit area vas and it requires ocular review or supersonic review for clefts and corrosion cheques. There should be proper review and enfranchisement by the competent review governments.

Suppression system: The maker of the system should be consulted and a suited care agenda implemented. If the system operates it should be checked by the maker and replaced after it has operated.

6.1 Advantages of the Preventive Care

An early cognition of at hand failure through the usage of tendency analysis techniques.

Actual cognition and accurate failure anticipation.

This attack can nail at hand component failure together with the cause of the failure.

It is flexible, if used with concurrence with an adaptative control and it can widen the utile life of works /equipment.


A Job Safety Analysis ( JSA ) should be done before the care to enable everyone get acquitted with the process of care and safety.

All operators should be to the full trained to be cognizant of the hazard appraisal and exigency safety processs. A agenda for the planned care of the works and safe processs for breakdown care should be available.

Procedures should be in topographic point to supply safety harness for working at tallness. Scaffold if erected must be inspected and checked.


There are many statute laws but three are closely relevant to maintenance at work. They include Health and Safety at work Act 1974 ( HASAWA ) , Working at Height Regulation 2005 ( WAHR ) , the Control of Noise at Work Regulation 2005.

Health and Safety at Work Act 1974

The act states that it shall be the responsibility of every employer to guarantee, so far as is sensible operable, the wellness and public assistance at work of all his employees, the proviso and care of works and systems of work that are safe and without hazards to wellness. The responsibility of the employee while at work to take sensible attention for wellness and safety of him and others who may be affected by Acts of the Apostless or skip at work ( 2010 ) .

Working at Height Regulations 2005

The ordinance addresses all facets of work at height including the choice and usage of equipment, and the manner the work is planned, organised and managed. The ordinances are intended to understate the hazard of falls whilst working at tallness ( 2010 ) .

Control of Noise at Work Regulation 2005

The ordinance requires the employer to measure the hazards to his employees from noise at work, take action to cut down the noise exposure that produces the hazard, supply employees with hearing protection, supply employees with preparation, and carry out wellness surveillance where there is a hazard to wellness. ( 2010 ) .