Watson-Marlow 300 User Manual

300 Series pumpheads ATEX Directive (94/9/EC)

1 Introduction

Directive 94/9/EC, commonly known as the ATEX directive, carries obligations to the person who places equipment on the market, in the EU territory, for use in potentially explosive environments. A number of pumps manufactured by WatsonMarlow are suitable for use in hazardous environments; ATEX compliant pumps from the 300 series are listed below, in Section 2 "Pump models".

All of Watson-Marlow's ATEX pumps have been rated as Group II, Category 2G 11B c T4 equipment. The 313 and 314 pumphead range is intended for use in gas based environments only. The pumpheads are sold individually (for use with customer specified ATEX drives) and in defined configurations supplied complete with ATEX drives.

This document provides specific ATEX information and should be used in conjunction with the original user manual.

2 Pump models

The following 313/314 pumpheads are covered by this manual:

313 and 314 ATEX Pumpheads

313DA*	033.3411.A00	3 roller, tongued drive fitting for 1.6mm wall tubing
313BA*	033.3421.A00	3 roller, bareshaft fitting for 1.6mm wall tubing
313XA*	033.3431.A00	3 roller, extension head for 1.6mm wall tubing
313XBA*	033.3441.A00	3 roller, bareshaft extension head for 1.6mm wall tubing
313D2A*	033.3511.A00	3 roller, tongued drive fitting for 2.4mm wall tubing
313B2A*	033.3521.A00	3 roller, bareshaft fitting for 2.4mm wall tubing
313X2A*	033.3531.A00	3 roller, extension head for 2.4mm wall tubing
313XB2A*	033.3541.A00	3 roller, bareshaft extension head for 2.4mm wall tubing
313B2A*	033.3521.AM0	3 roller, Manesty bareshaft fitting for 2.4mm wall tubing
313XB2A*	033.3541.AM0	3 roller, Manesty bareshaft extension head for 2.4mm
		wall tubing
314DA*	033.4411.A00	4 roller, tongued drive fitting for 1.6mm wall tubing
314BA*	033.4421.A00	4 roller, bareshaft fitting for 1.6mm wall tubing
314XA*	033.4431.A00	4 roller, extension head for 1.6mm wall tubing
314XBA*	033.4441.A00	4 roller, bareshaft extension head for 1.6mm wall tubing
314D2A*	033.4511.A00	4 roller, tongued drive fitting for 2.4mm wall tubing
314B2A*	033.4521.A00	4 roller, bareshaft fitting for 2.4mm wall tubing
314X2A*	033.4531.A00	4 roller, extension head for 2.4mm wall tubing
314XB2A*	033.4541.A00	4 roller, bareshaft extension head for 2.4mm wall tubing

* NB: these pumpheads are compatible with a number of Watson-Marlow cased drives. However, the Watson-Marlow cased drives are not ATEX compliant and must not be used in hazardous locations.

Any 313 or 314 pumpheads not listed here are NOT suitable for use in hazardous environments (at date of issue).

3 Hazardous environments

All of Watson-Marlow's ATEX pumps are classified as Group II, Category 2G IIB c T4 equipment under the definitions of 94/9/EC:

"Group II, Category 2 products should be designed to be capable of remaining within their operational parameters, as stated in the instruction manual, and based on a high level of protection for their intended use, in areas in which explosive atmospheres caused by mixtures of air and gases, vapours, mists or air/dust mixtures are likely to occur."

Furthermore, "The explosion protection relating to this category must function in such a way as to provide a sufficient level of safety even in the event of equipment with operating faults or in dangerous operating conditions which normally have to be taken into account".

Watson-Marlow pumps must not be used in the underground parts of mines, and in surface installations of such mines, likely to become endangered by firedamp and/or combustible dust.

NB: where two or more items of ATEX equipment are combined, the complete assembly shall carry the same rating as the lowest ranking individual piece of equipment.

4 Operating parameters

The following tube materials can be used with 313 and 314 ATEX pumpheads. Bore sizes range from 1.6mm to 8.0mm, with an option of 1.6mm or 2.4mm wall thickness:

Tubing: working temperature range

Marprene	5C to 80C
Bioprene	5C to 80C
Pumpsil platinum-cured silicone	-20C to 80C
STA-PURE PCS	0C to 80C
STA-PURE PFL	0C to 80C

The following parameters define the boundary of the safe working envelope - these values must not be exceeded (ATEX compliance will be invalidated):

313 and 314 pumpheads

Ambient temperature range	5C to 40C
Max peak pressure (0.5 to 4.8mm bore)	2 bar
Max peak pressure (6.4 to 8.0mm bore)	1 bar
Max continuous speed, 313	400 rpm
Max continuous speed, 314	300 rpm
Max intermittent speed	600 rpm
Corrosion resistance	See 8	Materials
Tube life	See 7	Tube life

WARNING! Do not run dry for excessive periods. Roller and tubing temperatures can exceed normal operating range.

WARNING! Do not run pumphead against a dead-end condition (closed discharge). This can lead to excessive roller and tubing temperatures and pressures in excess of the limits in the table above.

When two or more items of ATEX equipment are combined, the permissible operating envelope will be determined by the narrowest range after considering all values for a given parameter.

5 Potential pump hazards

As part of the requirements of 94/9/EC all potential hazards, including expected malfunctions, have been identified and subjected to a risk assessment. In order to prevent these ignition sources becoming effective a number of changes have been implemented. In addition to engineering modifications, the changes include additional operating instructions in order to specifiy correct usage in hazardous locations.

Recognised ignition sources

Surface temperatures of rollers and spindles

Tube burst and subsequent spilling of pumped fluid

Mechanical failure of rotor hub

Exothermic chemical reaction

Electrostatic discharge

Bearing failure

6 Installation guidelines

Please refer to the standard 313/314 pumphead manual (PB0210) for general installation instructions.

The 313/314 pumpheads achieve ATEX II 2G IIB c T4 equipment compliance for electrostatic discharge from non-conductive parts without modification. This is because the 313/314 pumphead projected surface area in any direction is less than 100cm2. EN13463-1:2009 par 7.7.4 for Gas Group IIB equipment states that there is a danger of electrostatic charge under normal conditions of use for equipment with greater projective area than 100cm2.

The bare shaft models need to be installed with the bareshaft connected to earth, this is usually achieved via the use of a suitable ATEX drive, it is the customers responsibility to ensure safe operation.

The effect of this is that a MAXIMUM OF TWO 313/314 PUMPHEADS can be used in a ganged, multi-channel, Group IIB equipment configuration.

If the tubing, external to the pumphead, comes into dynamic contact with another surface or is in proximity to an electrical/magnetic field, the tubing could become electrostatically charged. Tubing should be positioned to prevent this from occurring. The torque requirement for 313/314 ATEX pumpheads is 2.2Nm under worst-case conditions. A drive unit should be selected that can safely generate this torque below any overload condition. All Watson-Marlow close-coupled drives have been configured in this way with thermistors for thermal overload protection.

7 Tube life

A number of factors contribute to the life of the tubing:

Factors influencing tube life

Normal tube fatigue - dependant on tube size and material.

Incorrect tube loading - see 313/314 pumphead manual (PB0210) for guidance.

Excess working pressure - see Section 4 "Operating parameters" .

Chemical incompatibility - a table of tubing compatibility can be found on http://www.watson-marlow.co.uk/pdfs-global/wd-chemcompat-05.pdf Immersion kits are available from Watson-Marlow for testing.

For each application it is strongly recommended that tube life should be determined by trials, prior to installation in a hazardous environment. If this is not possible, or if there is any doubt in terms of tube life then the following hazards should be recognised before installing a pump in a potentially explosive atmosphere:

Chemical reaction between pumped fluid and pump materials - the materials of construction are LISTED IN SECTION 8.

Pumped fluid can be ignited by surface temperature of rollers - all Watson Marlow's ATEX equipment has been rated as T4 (meaning that even under worst-case operating conditions the maximum surface temperature will not exceed 135C).