Alfalaval SRU series User manual

IMPORTANT!
When ordering spare parts please quote Pump Serial No.
Read all of this pump manual and any instructions supplied for ancillary equipment before the unit is installed,
operated or maintained.
ESE02195-EN9 2020-02
Original manual
Instruction Manual
ATEX Addendum to SRU Instruction Manual - Rotary Lobe Pump - SRU Range

Table of contents
The information herein is correct at the time of issue but may be subject to change without prior notice
1. EC Declaration of Conformity ....................................................................... 4
1.1. ATEX Directive 2014/34/EU ...................................................................... 5
1.2. ATEX marking ..................................................................................... 5
2. Safety .................................................................................................... 6
2.1. Special conditions for safe use .................................................................. 6
2.2. General information ............................................................................... 6
3. Installation .............................................................................................. 7
3.1. Installation ......................................................................................... 7
4. Operation ............................................................................................... 8
4.1. Operation .......................................................................................... 8
4.2. Seal operation safety checks .................................................................... 8
4.3. Daily Checks ...................................................................................... 9
5. Maintenance ........................................................................................... 10
5.1. General Maintenance Guidelines ................................................................ 10
5.2. Ordering Spare Parts ............................................................................. 10
5.3. Mechanical seals .................................................................................. 11
5.4. Heating/Cooling devices ......................................................................... 15
5.5. Thermocouple ..................................................................................... 16
5.6. ATEX Pressure Relief Valve ...................................................................... 17
6. Technical data ......................................................................................... 20
6.1. Shaft Seals ........................................................................................ 20
6.2. Monitoring Seal Face Temperature .............................................................. 21
6.3. Seal Operation Data .............................................................................. 23
3

1 EC Declaration of Conformity
This declaration of conformity is issue under sole responsibility of the manufacturer:
Alfa Laval Eastbourne Ltd
Company Name
Brich Road, Eastbourne, East Sussex, BN23 6PQ United Kingdom
Address
[phone]
Phone No.
Equipment covered by this declaration of conformity:
Pump
Designation
SRU1, SRU2, SRU3, SRU4, SRU5, SRU6
Type
From serial number E222350 to E500.000
Is in conformity with the requirements of the following directives:
2006/42/EC Machinery Directive
2014/34/EU Equipment Explosive Atmospheres (ATEX)
This declaration of conformity covers pumps with the following ATEX markings:
II 2G Ex h IIB T4 .. T2 Gb II 3G Ex h IIB T4 .. T2 Gc
II 2G Ex h IIC T4 .. T2 Gb II 3G Ex h IIC T4 .. T2 Gc
For ATEX directive 2014/34/EU the following harmonized standards EN 80079-36:2016 and EN 80079-37:2016 for non-electrical
equipment have been applied.
ATEX directive 2014/34/EU conformity for the motor and coupling is covered by the relevant EU Type examination certificates
and declarations supplied by the manufacturers.
The Pump Technical file is stored with: Teknologisk Institut, Kongsvang Alle 29, 8000 Aarhus C, Denmark
Notified Body no.: 0396
Archive no.: 2019-1-0330A
The person authorized to compile the technical file is the signer of this document
Global Product Quality Manager
Pumps, Valves, Fittings and Tank Equipment Lars Kruse Andersen
Title Name Signature
Alfa Laval Kolding, Albuen 31, DK 6000 Kolding 2020-02-11
Place Date
(This Declaration of Conformity replaces Declaration of Conformity dated 2018-06-01)
4

1 EC Declaration of Conformity
1.1 ATEX Directive 2014/34/EU
ATEX Directive 2014/34/EU
The ATEX Directive 2014/34/EU covers equipment and protective systems that will be used in areas endangered by potentially
explosive atmospheres created by the presence of flammable gases, vapors and dusts.
Rotary Lobe Pumps supplied with an ATEX symbol are classified for use in potentially explosive gas and vapour atmospheres
under ATEX Directive 2014/34/EU Group II, Categories 2 and/or 3.
Technical File Ref: 2019-1-0330A
Equipment Group and Category: Group II Category 2G Zone 1
Group II Category 3G Zone 2
Standards Used: EN 80079-36:2016, EN 80079-37:2016
1.2 ATEX marking
In addition to the standard pump nameplate, ATEX Certified units have an additional ATEX name plate affixed to the pump
gearbox housing stating the unit ATEX certification standard.
Name plate example:
Manufacturer
Pump Type
Serial No.
Tech. File ref.
Year
Alfa Laval Eastbourne Ltd.
BN23 6PQ, UK
3204-0006
SRU4 / 055 / LS
E250789 20
II 2G Ex h IIB T4 Gb
DTI 19ATEX0330
5

2Safety
Unsafe practices and other important information are emphasized in this manual. Warnings are emphasized by means of special
signs, see description in Standard Instruction Manual section 2.1 Special Conditions for Safe Use and 2.2 General Information.
Always read the manual before using the pump!
2.1 Special conditions for safe use
!
-Ensure checks and running conditions for the pump unit during operation to be according to section 4 Operation
-Never operate pump outside max duty conditions specified in section 6.3 Seal Operation Data. If the duty conditions
change please refer to pump manufacturer.
2.2 General information
!
-Always make sure that the Serial Number Stamped on the pump nameplate matches the number shown on the Declaration
and in section 6.3 Seal Operation Data
-Always check that the components and equipment supplied is suitable for the area intended and corresponds with the
order acknowledgement.
-Always read this ATEX addendum thoroughly before using the pump and read the safety instructions in the Standard
Instruction Manual prior to handling, installing, operating or maintaining the pump.
-Always order genuine spare parts using the serial number of the pump, stated on the pump nameplate, for identification
purposes.
-Always ensure that intentionally or potentially mixing of fluids do not create hazardous reactions/situations (eg. process
media and flush media)
Education:
Operators must have necessary knowledge about the pump supplied including the mechanical seals before doing any
installation or maintenance work relating to the pump unit. Necessary knowledge includes the understanding of the:
-functio
n of the pump unit including the mechanical seal
- maintenance/service procedures of the pump unit including the mechanical seals.
- safety instructions.
-operat
ional limits for the pump unit including the mechanical seals
Installation
- Always read section 3 Installation
Operation
-Alwa
ys read section 4 Operation
Maintenance
- Always read section 5 Maintenance
6

3 Installation
3.1 Installation
!
Pumps and motorized pump units
-Always follow the Installation instructions in the Standard Instruction Manual in conjunction with this addendum
-Always ensure that instructions for all ATEX compliant equipment and components are followed (motors, couplings,
reduction gears etc.)
-Always make sure that pump gearbox, base plate and motor are electrically earthed
-Always read section 4 Operation before pump start up
-Ensure correct alignment of pump and drive unit
-Ensure that all control and monitoring equipment complies with the requirements in appropriate ATEX standards e.g.
EN 13463-6
-Never install the pump or pump unit at an angle of more than 5° from the horizontal plane
-Never cover up pump gearbox, motor or reduction gearbox in any way that will reduce the cooling effects intended
Thermocouple installation See section 5.3.2 and 5.3.5 5 Maintenance
For pumps fitted with the ATEX Pressure Relief Valve please see section 5.6 ATEX Pressure Relief Valve
!
Flush system
-Always connect the two flush housings in series, see examples in the sketch below.
-Always measure flush media parameters at flush housing outlet eg. temperature, flow and/or pressure (see section 6.1 6
Technical data, for more information)
-Ensure inlet connection to be lower than outlet connection on the individual housing
-Ensure the distance between the flush housing outlet and the flush media temperature sensor (if optional thermocouple is
fitted) does not exceed 200mm. For information on required flows, pressures etc. (see section 6.1 6 Technical data).
Flush outlet
Flush Flush
outlet outlet
Link
pipe
Flush
inlet
TD 243-110
TD 243-112
Link pipe Flush
inlet
7

4Operation
4.1 Operation
!
Pump units
-Always read the operations instructions in the Standard Instruction Manual
-Always read “Technical information” for shaft seals in section 6.1 6 Technical data
-Always vent and purge the seal cavities and flush housing (if applied) of air/gas prior to start-up to avoid any dry-running.
-Always make a visual inspection of the pump unit at startup to ensure there are no malfunctions e.g. leaks, abnormal noises,
vibration or heat. If found the equipment must be stopped immediately and the cause rectified.
-Always remove the rotorcase cover to drain the pump head
-Ensure that the temperature of the heating jacket/saddle, if fitted, does not exceed those shown in section 5.4
Heating/Cooling devices
-Never run pump with suction side and/or pressure side blocked
-Never operate other equipment/components in pump unit outside limits specified in manufacturers instructions manuals eg.
motor, reduction gear, coupling etc.
-Never expose thermocouple lead (if fitted) to any force higher than 5N (eg. high pressure cleaning etc.)
-Never use a heating/cooling media in saddles/jackets, that can cause a hazardous situation in case of leakage
-Never run the pump dry unless a flushed mechanical seal is fitted and operated correctly.
4.2 Seal operation safety checks
Pumps fitted with Double Flushed Mechanical Seals
The end user is required to ensure that:
- Flush media is present.
- Flush media is at a pressure of 1.0 bar min. above the pump discharge pressure.
- Seal faces are receiving the required volume of flush media, so as to cool them and dissipate any heat build up.
In practice this means the end user should monitor:
- Flush media pressure.
- Flush media flow rate.
and must monitor:
- Temperature - either of flush media or change of temperature at outboard seal face.
Pumps fitted with Single Flushed Mechanical Seals
The end user is required to ensure that:
- Flush media is present.
- Seal faces are receiving the required volume of flush media, so as to cool them and dissipate any heat build up.
In practice this means the end user should monitor:
- Flush media pressure or flow rate.
and must monitor:
- Temperature of flush media.
Pumps fitted with Single Mechanical Seals
The end user is required to ensure that:
- Seal face temperature does not exceed the temperature class limit.
In practice this means the end user must monitor either:
- Presence of pumped media either by flow rate or pressure indicator.
- Pumped media temperature.
or alternatively:
- Seal face temperature change.
8

4Operation
4.3 Daily Checks
Shaft seals, all types:
- Ensure there is no unacceptable leakage.
Shaft seals fitted with optional thermocouple:
- Ensure proper function of signals, alarms and associated Ignition Prevention Systems related to the thermocouple.
- Ensure for single seal, that the thermocouple reading is similar to the process media temperature (no more than 20°C
above). If this is not the case, the equipment must be stopped immediately, checked and the cause rectified. Check
for abnormal running conditions.
- Ensure, for double flushed mechanical seals, that the thermocouple reading is similar to the flush media temperature (no
more than 20°C above). If this is not the case, the equipment must be stopped, checked and the cause rectified. Check
for abnormal running conditions.
Pump unit:
- Ensure the oil levels to be correct with no signs of oil contamination.
- Ensure there are no signs of overheating.
- Ensure there are no abnormal running conditions such as loose components, abnormal noise, vibration , heat or oil leakage.
If found the equipment must be stopped immediately and the cause rectified.
- Ensure the pump duty conditions and running speed never exceed the limits specified in section 6.3 Seal Operation Data
- Ensure all sealing elements are effective to prevent ingress of solid foreign objects and liquids.
- Ensure exterior surfaces are clean and free from any dust deposits.
Control / Monitoring equipment:
- Ensure, at least daily, correct function of control and monitoring equipment so as to ensure surface temperatures stay within
the specified temperature class (eg. process media temperature/pressure sensors).
- Ensure, at least daily, correct function of signals, alarms and associated Ignition Prevention Systems so as to ensure surface
temperatures stay within the specified temperature class.
NOTE:
Any maintenance work must be carried out when an explosive atmosphere is not present. Additionally, prior to any maintenance
work the equipment must be electrically and mechanically isolated.
9

5 Maintenance
5.1 General Maintenance Guidelines
-Always follow the Maintenance instructions in the Standard Instruction Manual
-Always read “Technical information” section 6.1 Shaft Seals and section 6.3 Seal Operation Data
-Always ensure that instructions of all ATEX compliant equipment and components are followed (motors, couplings,
reduction gears etc.)
-Always read section 4 Operation before starting up the pump unit after maintenance
Pump Gearbox
It is essential to ensure the oil level to be correct as specified in the standard instruction manual. Recommended oil as follows:
(-20 to +130°C)
Castrol Alphasyn PG150
Mobil Glygoyle 22
Shell Omala S4 WE 150
Chevron Meropa Synlube WS 150
(+130to+200°C)
Castrol Alphasyn PG 220
Mobil Glygoyle 30
Shell Omala S4 WE 220
Chevron Meropa Synlube WS 220
Food Grade (-20 to +130°C)
Mobil Glygoyle 150
Total Nevastane XSH 150
Fusch Cassida Fluid GL 150
Pump Gearbox bearings changing intervals
If the bearings are worn excessively it can cause increased friction and thus increased surface temperature on the gearbox.
Gearbox bearings should be renewed before the running hours stated in the table below have been exceeded.
Alternatively it should be ensured by other means that the bearings are working satisfactorily eg. bearing frequency analysis.
The bearings should be checked/monitored continuously or at least every 1000 running hours when the running hours in the
table below are exceeded.
Bearing changing intervals (pump running hours x1000)
Process media differential pressure
Pump model
0to8bar 8to10bar 10to15bar
SRU1/005 30 Non-applicable Non-applicable
SRU1/008 30* Non-applicable Non-applicable
SRU2/013 30 30 9
SRU2/018 20 10 Non-applicable
SRU3/027 30 30 30
SRU3/038 30 30 Non-applicable
SRU4/055 30 30 13
SRU4/079 30 18 5.5
SRU5/116 30 30 20
SRU5/168 30 25 8
SRU6/260 20 12 3.8
SRU6/353 12 6 2
* Or maximum rated pump differential pressure, whichever is lower.
5.2 Ordering Spare Parts
When ordering spare parts please quote Pump Serial No.
10

5 Maintenance
5.3 Mechanical seals
Mechanical seals should not be removed unless they are to be replaced.
5.3.1 R90 Single mechanical seal
Refer to section 4.5.1 in Standard Instruction Manual
5.3.2 R90 Single mechanical seal with optional thermocouple
Rotor
Shaft Setting Item Description
Dinemsion 71 Stationary seal ring O-ring
72b Stationary seal ring with thermocouple
Pump Setting Dimension Grub Screw (78) 73 Rotary seal ring O-ring
mm in Torque (Nm) 74
SRU1 33.6 1.32 4.5
SRU2 35.6 1.40 4.5
SRU3 38.1 1.50 4.5
Rotary seal assembly comprising of rotary seal
ring, Washer (98), wave spring (99), drive ring (100)
and grub screw (78)
SRU4 39.6 1.56 4.5 101 Thermocouple clamp plate
SRU5 47.6 1.87 8 102 Clamp plate screw
SRU6 50.7 2.00 15 103 Plastic bush
104 Bush locking screw
Seal removal
1. Unplug or disconnect the thermocouple lead connection – keep lead clamped to rotorcase until rotorcase removed
2. Remove the rotorcase, cover, rotors and rotorcase
3. Loosen bush locking screw (104)
4. Extract the stationary seal ring (72b) ensuring not to damage thermocouple wire, and remove o-ring (71)
5. Loosen the grub screws (78)
6. Remove the rotary seal assembly (74) from the shaft.
7. Remove abutment spacer if fitted.
8. Extract the rotary seal O-ring (73) from the rotary seal assembly
11

5 Maintenance
Seal fitting
1. Mark the shaft to indicate the seal setting length.
2. Lightly lubricate O-rings (71 and 73) with appropriate grease and fit to rotary and stationary seals (74 and 72).
3. If fitted replace abutment spacers.
4. Slide rotary seal assembly on to the shafts until aligned with the setting dimension mark.
5. Tighten the grub screws (78) to the recommended torgue figure as shown above.
6. Press stationary seals into rotorcase bores ensuring the thermocouple wire is oriented towards the center of the rotorcase.
7. Fit lead through thermocouple fixture and position plastic bush (103) in the fixture.
8. Tighten the bush locking screw (104), torque 4Nm, holding the static seal face in place. Do not apply more than 5N
force to lead.
9. Wipe clean the sealing faces with solvent.
10. Refit the rotorcase, rotors and front cover.
11. Make sure the lead from the thermocouple is mounted properly and kept away from any moving parts and sharp edges.
12. Connect the flying leads of the thermocouple to data system, type K connection
13. Verify the function and reading of the thermocouple. If there is no signal, the thermocouple has been damaged or incorrectly
connected.
14. Verify proper function of seal and temperature reading at startup, see section 6.3 Seal Operation Data
For horizontally ported pumps, the thermocouple is fitted on the upper shaft and for vertically ported pumps the thermocouple
can be fitted on either shaft.
The components and equipment used for the monitoring system must comply with the requirements of appropriate ATEX
standard e.g. EN13463-6.
For further information on the installation and operation of the Thermocouple please see section 5.5 Thermocouple
12

5 Maintenance
Mechanical seals should not be removed unless they are to be replaced.
5.3.3 R90 Single flushed mechanical seal
Refer to section 4.5.2 in Standard Instruction Manual
5.3.4 R90 Double flushed mechanical seal
Refer to section 4.5.3 in Standard Instruction Manual
5.3.5 R90 Double flushed mechanical seal with optional thermocouple
Item Description
71 Stationary seal ring O-ring
72 Stationary seal ring
72c Stationary seal ring with thermocouple
73 Rotary seal ring O-ring
74a Rotary seal ring assembly - inboard Comprising of
rotary seal ring, washer (98), wave spring (99) and
drive ring (100)
74b Rotary seal ring assembly - outboard Comprising
of rotary seal ring, grub screw (78), washer (98)
and wave spring (99)
75 Seal housing gasket
79 Seal housing
103 Plastic bush
104 Bush locking screw
Type Torque Nm Outboard
SRU1 4.5
SRU2 4.5
SRU3 4.5
Series 1, the outboard seal
fits over the inboard seal.
SRU4 4.5 Inboard
SRU5 15.0
SRU6 15.0 Inboard
SRU4 4.5
SRU5 15.0
SRU6 15.0
Series 2-6, the inboard seal
fits over the outboard seal.
Outboard
13

5 Maintenance
Seal removal
1. Ensure the flush media is turned off and disconnect the flushing pipework.
2. Remove the rotorcase cover and rotors.
3. Turn the drive shaft until the drive ring grub screws (78) are visible through the flushing connections.
4. Loosen the grub screws.
5. Remove the rotorcase.
6. Remove seal housings (79) complete with rotary seal assemblies (74a and 74b) and outboard stationary seals.
7. Loosen bush locking screw (104) on thermocouple fixture and extract carefully without damaging the thermocouple wire.
8. Extract the seal housing gasket (75), stationary seal ring (72) and O-ring (71) from the rotorcase.
Seal fitting:
Ensure seal orientation is correct.
1. Lightly lubricate O-rings (71 and 73) with appropriate grease and fit to rotary seal assemblies and stationary seal rings
(74A, 74B and 72).
2. Fit stationary seals into the rotorcase bores and seal housings (79) making sure the thermocouple lead is positioned at
the thermocouple fixture.
3. Fit lead carefully through thermocouple fixture and position plastic bush (103) in the fixture. Do not apply more than 5N
to the lead.
4. Tighten the bush locking screw (104), torque 4Nm, holding the static seal face in place. Do not apply more than 5N
force to lead.
5. Fit gaskets (75) into the rotorcase bores.
6. Wipe clean the sealing faces with solvent.
7. Locate rotary seal assemblies and fit the seal housings to the rotorcase ensuring that the grub screws (78) are accessible
so they can be tightened.
8. Refit the rotorcase.
9. Turn the drive shaft until the grub screws are visible through the flushing connections.
10. Tighten the grub screws to the recommended torque figure as shown on page 13.
11. Refit the rotors and rotorcase cover.
12. Make sure the lead from the thermocouple is mounted properly and kept away from any moving parts and sharp edges.
13. Connect the flying leads of the thermocouple to data system, type K connection
14. Verify the function and reading of the thermocouple. If there is no signal, the thermocouple has been damaged or incorrectly
connected.
15. Verify proper function of seal and temperature reading at startup, see section 6.3 Seal Operation Data
16. Verify proper function of overall pump unit at startup
For horizontally ported pumps, the thermocouple is fitted on the upper shaft and for vertically ported pumps the thermocouple
can be fitted on either shaft.
The components and equipment used for the monitoring system must comply with the requirements of appropriate ATEX
standard e.g. EN13463-6.
For further information on the installation and operation of the Thermocouple please see section 5.5 Thermocouple.
14

5 Maintenance
5.4 Heating/Cooling devices
SRU pumps have the option of being fitted with jackets to the rotorcase cover and/or saddles to the rotorcase. These
are primarily used for heating the pumphead so as to maintain the pumped media temperature. They may also be used
for cooling purposes.
Saddle
Connections
Screw for steam,
hot/cold fluid
Jacket
TD 243-087
The maximum allowable pressure and temperature of heating/cooling fluid is 3.5 bar and 150°C respectively, except in T4
applications in which the maximum allowable temperature is 115°C.
15

5 Maintenance
5.5 Thermocouple
Thermocouple Installation and Operation
Thermocouples are fitted to the Pressure Relief Valve option and are offered as an option to monitor the mechanical seal
temperature.
The thermocouples supplied are Type-K.
The thermocouple/s needs to be connected to a suitable Ignition Prevention System (IPS) conforming to Ignition Protection
Level 1 (IPL1) as per the appropriate requirements of EN ISO80079-37:2016, Clause 7. It is the user’s responsibility to asses
and ensure that the selected Ignition Prevention System is suitable for the intended application.
Prior to connecting the thermocouple sensor to a suitable Ignition Protection System, the user shall observe all ATEX
requirements of the selected Ignition Protection System and ensure the assembly (i.e. the thermocouple sensor and any other
part/devicethatformstheIgnitionProtection System) shall not itself be an ignition source. The thermocouple sensor shall be
fitted to the selected Ignition Prevention System by means of a suitably certified IS barrier and by competent personnel.
Pressure Relief Valve (if fitted)
The Ignition Prevention System shall be set up appropriately so as to shut the equipment down in the event of the the front
cover surface temperature exceeding the below values when measured on the thermocouple sensor fitted to the front cover
relief valve assembly:
T4 (135°C) = 115°C or maximum rated pump temperature (whichever is lower)
T3 (200°C) = 150°C or maximum rated pump temperature (whichever is lower)
T2 (300°C) = 150°C or maximum rated pump temperature (whichever is lower)
The Ignition Protection System shall cause the equipment to shut down within the maximum permitted rundown time of 30
seconds in the event of the above temperatures being met.
Mechanical Seal Thermocouple (if fitted)
The Ignition Prevention System shall be set up appropriately so as to shut the equipment down in the event of the seal face
temperature exceeding that stated in the ’Seal Operating Data - Section 6.3’. The limits shown below are maximum limits
which are not to be exceeded:
T4 (135°C) = 115°C or maximum rated pump temperature (whichever is lower)
T3 (200°C) = 150°C or maximum rated pump temperature (whichever is lower)
T2 (300°C) = 150°C or maximum rated pump temperature (whichever is lower)
The Ignition Protection System shall cause the equipment to shut down within the maximum permitted rundown time of 5
seconds in the event of the above temperatures being met.
For more details on monitoring seal face temperature see section 6.2 Monitoring Seal Face Temperature
16

5 Maintenance
5.6 ATEX Pressure Relief Valve
The below instructions replace those shown in the Installation Manual, pages 35 & 36.
3204-0007
Item Description Item Description
1Rotorcase cover 14 Circlip
2 Hydraulic piston 15 Bush
3O-ring, hydraulic piston 16 Valve guide
4Valve pin 17 Valve pin
5Shim 18 Spring
6Backstopdisc 19
Screw
7O-ring, backstop disc 20 Valve spring guide
8Bush 21
Spring adjuster
9Screw, backstop disc 22 Washer
10 Valve shaft 23 Notched nut
11 O-ring, pneumatiic piston 24 Valve housing
12 Pneumatic piston 25 Screw
13 O-ring, pneumatic piston 26 Screw, spring adjuster
27 Thermocouple
17

5 Maintenance
5.6.1 Relief Valve Disassembly
1. Unplug or disconnect the thermocouple lead connection (27).
2. Remove manual override lever if fitted.
3. Remove screws (25) and valve housing (24).
4. Remove notched nut(s) (23) and spring adjuster (21), If springs are still compressed when the notched nut reaches end of
thread, release the spring adjuster screws (26).
5. Remove springs (18) (series 1-5), spring stacks (series 6), screws and valve guide (16).
6. Remove circlip (14) and pneumatic piston (12).
7. Remove screws, backstop disc (6) and hydraulic piston (2).
8. Unscrew hydraulic piston (2) from valve shaft (10) and remove O-rings (3, 7, 11 and 13).
5.6.2 Relief Valve Assembly
New O-rings should be fitted during assembly.
Clean components before fitting; check there is no damage to faces.
1. Lubricate all o-rings.
2. Fit O-ring (7) to backstop disc (6) and fit backstop disc to valve shaft (10).
3. Fit O-ring (3) to hydraulic piston (2) and screw onto valve shaft.
4. Locate assembly into rotorcase cover, replace backstop disc screws (9).
5. Fit pneumatic piston o-rings (11 and 13) and locate assembly on valve shaft. Replace circlip (14) and springs (18). (Series 6
pumps only - each spring stack should contain an equal amount of springs, noting correct orientation). Place valve guide
(16) over springs and replace screws (25).
6. Fit spring adjuster (21) and notched nut (23), valve housing (24) and screw (25).
7. Replace manual override lever if applicable.
8. Connect the thermocouple (27) to the data system.
9. Verify the function and reading of the thermocouple. If there is no signal, the thermocouple has been damaged or incorrectly
connected.
5.6.3 Valve Adjustment
The relief valve will require setting to suit duty requirements.
Note: A gauge is required to measure discharge pressure during adjustment.
1. Stop the pump.
2. Removevalvehousing(24).
3. Release notched nut(s) (23) to end of thread.
4. Insert a thin rod into valve guide (16) and mark to indicate closed position.
5. Start pump and increase pressure noting pressure gauge reading when the rod starts to move. This indicates the valve is
beginning to open.
6. Tighten the notched nut gradually until desired system pressure is achieved (Series 6 pump only - evenly tighten the spring
stack nuts after adjusting the notched nut).
7. Apply thread locking adhesive to the notched nut after relief valve is set.
8. If pneumatic override is required connect air supply and adjust pressure until valve opens. Check piston reseats when
air supply is disconnected.
18

5 Maintenance
Pressure Relief Valve Operation
The relief valve fitted to pumps certified for use in ATEX areas are fitted with a thermocouple used to measure the surface
temperature of the front cover.
During pump running, if the relief valve operates, the increased product slip (internal product recirculation) within the pump head
can cause an increase in pumped product temperature and thereby allowing an uncontrolled increase in the pump head surface
temperature beyond that allowed under the ATEX T-rating certified.
The thermocouple allows monitoring of the front cover surface temperature during use and is to be used to ensure that
in the event of an abnormal temperature increase being detected, the pump equipment is shut down to stop any further
temperature rise.
Inadditiontothethermocoupleitisrecommendedthat,toensuresafeoperationofboththepumpandotherpiping
system/components, that the line pressure is monitored as close to the pump discharge port as possible to ensure equipment
shut down if an over pressure event occurs and the cause investigated and rectified before restarting.
19

6 Technical data
6.1 Shaft Seals
The correct function of a mechanical seal is largely dependent upon its lubrication and cooling of the sealing surfaces. It is
therefore extremely important to avoid any dry-running of the seal faces since this can cause excessive generation of heat and
thus the possibility of exceeding the specified temperature class. During normal operation a mechanical seal will generate a very
small but controlled leakage which will increase upon failure. If dry-running of the process media cannot be avoided or if any
leakage of the process media can cause a hazardous situation (i.e. flammable media), a flush system must be fitted.
The standard ATEX compliant mechanical seal options are described below:
A. Double Flushed Mechanical Seal
This seal arrangement provides the user with the highest level of protection against the seal faces running hot. On this
seal arrangement the flush is used as a ‘Barrier’ fluid. The pressure of the barrier fluid should be 1.0 bar min. above the
pump discharge pressure. The inboard seal interface film will therefore be flush media. The barrier fluid will act as a coolant
and lubricant for both inboard and outboard seals. Leakage of pumped media into the barrier fluid will not occur. Flush
housings should be connected in series (not parallel) as shown in section 3.1 Installation. Proper function of the flush system
is essential - if the flush flow is interrupted or stopped the outboard seal will run dry and the seal face temperature increased
to become a potential explosion risk, see section 6.2 Monitoring Seal Face Temperature
Adoublemec
hanical seal fitted with a thermocouple allows the user to provide alarms based on the temperature at the seal
face, see section 6.2 Monitoring Seal Face Temperature
Thermosyphon flush systems are not recommended.
B. Single Flushed Mechanical Seal
This seal arrangement provides the user with a high level of protection against the seal faces running hot.
On this seal arrangement the flush is used as a ‘Buffer’ fluid. The pressure of the buffer fluid should be 0.5 bar max. The seal
interface film will therefore be pumped media. The buffer fluid will act as a coolant for the seal and prevent the pumped
media from coagulating, solidifying or crystallising on the seal faces. Any leakage of pumped media is carried away to ensure
good seal function. Flush housings should be connected in series (not parallel) as shown in section 3.1 Installation. Proper
function of the flush system is essential - if the flush flow is interrupted or stopped the seal will run dry and the seal face
temperature increased to become a potential explosion risk, see section 6.2 Monitoring Seal Face Temperature
Note: A double flushed mechanical seal can also be operated in a low pressure flush mode as above.
C. Single Mechanical Seal
On this seal arrangement the seal interface film is the pumped media. The pumped media acts as a coolant and lubricant for
the seal faces. For single mechanical seals without a thermocouple fitted there is no monitoring device or protection and
relies on the process media to cool and lubricate the seal faces to stay within the stated temperature class. The process
must be controlled / monitored to ensure the seal faces do not exceed the temperature limit. This can be achieved by
ensuring there is a reasonable flow of the process media and the process temperature does not exceed the values listed in
the ‘Seal Operation Data’, section 6.3 Seal Operation Data
A single mechanical seal fitted with a thermocouple allows the user to provide alarms based on the temperature at the seal
face, see section 6.2 Monitoring Seal Face Temperature
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