Delta Controls 721 - Manual

GENERAL
The unit is manufactured, checked and supplied in
accordance with our published specification, and when
installed and used in normal or prescribed applications,
with the lid in place and within the parameters set for
mechanical and electrical performance, will not cause
danger or hazard to life or limb.
HEALTH AND SAFETY AT WORK ACT 1974
WARNINGS
1. THE USERS ATTENTION IS DRAWN TO THE
FACT THAT, WHEN THE UNIT IS ‘LIVE’ WITH RESPECT
TO ELECTRICAL SUPPLIES, A HAZARD MAY EXIST IF
THE UNIT IS OPENED OR DISMANTLED.
2. UNITS MUST BE SELECTED AND INSTALLED BY
SUITABLY TRAINED AND QUALIFIED PERSONNEL IN
ACCORDANCE WITH APPROPRIATE CODES OF
PRACTICE SO THAT THE POSSIBILITY OF FAILURE
RESULTING IN INJURY OR DAMAGE CAUSED BY
MISUSE OR MISAPPLICATION IS AVOIDED.
CAUTIONS
It is advisable to avoid the condition where the ambient
temperature is within ± 5 °C of the sensed temperature , as
this will increase the switching differential.
OPERATING PRINCIPLES
A closed system containing an equilibrium of liquid and
vapour of a suitable volatile chemical or gas is used to
sense the process temperature. The pressure within the
system is proportional to the applied temperature. This
pressure is applied to the bellows which transmits a force,
proportional to the temperature, to an operating beam.
The beam is restrained by an adjustable spring. When the
force on the beam overcomes the spring tension the beam
moves and operates a switch or switches. On reduction of
the applied temperature the force applied to the beam also
falls, the beam is restored to its original position by the
spring, and the switch resets.
INSTALLATION
The instruments are designed to be mounted vertically with
the thermowell connection underneath. They can be
mounted either direct to process (rigid stem) or to a wall or
panel using the backplate provided. Select the mounting
point so as to avoid excessive shock, vibration or
temperature fluctuation. Instruments should be mounted
to avoid excessive heat transfer from the process lines or
adjacent plant.
Capillary version
Mount the sensing bulb so that the capillary end is above
the bulb and the bulb is level with, or no more than 250
mm below the base of the instrument. The bulb is fitted
with a sliding compression gland to accommodate different
thermowells.
When fitting the instrument lid make sure gaskets and ‘O’
rings are in good condition and fitted correctly.
CAUTION: For the rigid stem version it is recommended
that a portion of flexible conduit be used to prevent undue
stresses being applied to the unit. For immersion lengths
refer to figs 9, 10.
WARNING: CHECK THE CONNECTION THREAD SIZE
AND SPECIFICATION TO AVOID MISMATCHING WITH
THE PROCESS CONNECTION ADAPTOR. SEE DIGIT
11 OF THE PRODUCT CODE.
PRODUCT CODE
ENCLOSURE
MODEL
ELECTRICAL ENTRY
MATERIAL OF WETTED PARTS
RANGE
SWITCHING OPTIONS
PROCESS CONNECTION
OPTIONS AND TREATMENTS
SPECIAL ENGINEERING
WIRING (Fig 1)
Wire in accordance with local and National codes. Use
cables no larger than 2.5 mm
2 (14AWG). Deliver electrical
connection through a suitable cable gland which will
maintain the IP rating of the instrument. Insert bare wires
fully into the terminal block and tighten securely. Keep
wiring tails to a minimum and check that wires do not
interfere with the operating mechanism. Use the earthing
points provided.
CERTIFIED ENCLOSURES
All Series 700 Temperature Switches can be supplied with
BASEEFA certified enclosures to the following standards:
Zone 1 (Div 1) IEC 60079-0 and IEC 60079-1
CENELEC EN50 014 and EN50 018
Codes ‘H’ for
aluminium and ‘K’ for cast iron II 2GD Exd IIC T6
ENCLOSURES W, N
Zone 2 (UK Only)
BS 4683: Part 3, Enclosure Code ‘N’. ExN IIT6.
All enclosures are suitable for outdoor use and the majority
of products are rated IP66. Refer to the product label and /
or leaflet. Only operation, maintenance or repair
procedures either contained herein or approved by Delta
Controls may be used, to avoid rendering the equipment
unsafe in operation and / or nullifying the Certification. NO
MODIFICATIONS ARE PERMITTED.
Electrical Adaptors
Zone 1. Use only certified adaptors for Zone 1.
WARNING: IT IS A REQUIREMENT OF SAFETY THAT
AT LEAST 5 FULL THREADS ARE ENGAGED
BETWEEN THE ADAPTOR AND CONDUIT ENTRY.
TAKE CARE TO SELECT AND INSTALL ADAPTORS
THAT DO NOT REDUCE THE ENCLOSURE IP RATING.
Zone 2
Adaptors used must have equivalent IP rating to the
enclosure and be impact resistant to 7Nm.
References for Selection and Installation
IEC 60079-14 for Enclosure Codes H and K
IEC 60079-14 for all Enclosure Codes (Intrinsic Safety)
EN 50021 for Enclosure Code N
IEC 50029 IP RATING (Ingress Protection)
MAINTENANCE
Inspections should be carried out at quarterly to yearly
intervals depending upon operating conditions.
Isolate the unit from process and power and remove the
lid. Check all terminals for tightness. Check that cable
tails are not fouled or chafed. Check for internal
condensation. Rectify as necessary.
It is recommended that instruments used to provide an
alarm are operated periodically to ensure they are
functioning correctly. If further maintenance is required
seek advice from DELTA CONTROLS before attempting
repair or replacement of parts.
CAUTION
Moving parts have been treated with a water repelling
lubricant before leaving the factory. Occasional inspection
and the application of a water repelling lubricant is
recommended to ensure moving parts remain free under
all conditions.
WARNING: DOES NOT APPLY TO OXYGEN SERVICE
Zone 1 enclosures
Thread seal and contact surfaces must be lightly lubricated
using a non-setting non-corrosive grease compatible with
the nitrile lid seal. Do not use copper bearing grease on
aluminium. Screw on lid hand tight making sure that
mating surfaces of the lid and enclosure are in contact.
Retighten the lid lock screw.
WARNING: IT IS A SAFETY REQUIREMENT THAT AT
LEAST 5 FULL THREADS ARE ENGAGED WHEN THE
UNIT IS IN OPERATION. NEVER OPERATE THE UNIT
UNLESS THIS CONDITION IS MET. DO NOT USE
GREASES OR LUBRICANTS NOT COMPATIBLE WITH
THE ENVIRONMENT OR PROCESS.
Weatherproof Enclosure (W) and (N)
If lid gasket is dried out or damaged, replace with new
greased gasket.
Stainless Steel Weatherproof Enclosure (A)
Check gasket. If damaged, replace.
On enclosures H, and K, remove the lid using an
appropriate tool if tight, eg edge of a spanner or a metal
rod (fig 1A).
ENCLOSURE A
ENCLOSURES H, K, M
OPERATION
Temperature switches are supplied calibrated against
falling temperature unless otherwise specified. Set Point
adjustment refers to falling temperature. Switching
differential is the difference between the set point and the
operating
value on rising temperature. Before
commencing adjustments or removing the lid, isolate the
instrument from process and power.
Set Point Adjustment: Models 721, 722, 723, 731, 732,
733, 771, 772, 773 (Fig 2)
1. Loosen the M3 hexagon head locking screw.
2. Rotate the 20 mm A/F hexagon head adjuster knob to
move the indicator along the calibrated scale. Rotate
clockwise to increase the set point and counter clockwise
to decrease the set point.
3. Retighten the locking screw taking care not to over
tighten.
4. Replace the instrument lid (see maintenance).
Set Point Adjustment: Model 781, 734, 774 (Fig 3)
The model 781, 734, 774 provides 2 microswitches which
can be set independently against individual scales using a
special dual beam mechanism. This fulfils the need for HI
LO switching. Adjust as follows:
1. Loosen the rear M3 hexagon head locking screw.
2. Rotate the rear adjuster screw to move the indicator on
the right hand (LO) calibrated scale. Rotate clockwise to
increase the set point and counter clockwise to decrease
the set point.
3. Retighten the locking screw.
4. Loosen the front hexagon head locking screw.
5. Rotate the front adjuster screw to move the indicator on
the left hand (HI) calibrated scale. Rotate clockwise to
increase the set point and counter clockwise to decrease
the set point.
6. Tighten the locking screw.
7. Replace the instrument lid (see maintenance).
Switching Differential Adjustment: Model 722, 732, 772
(Fig 4)
1. Rotate the knurled plastic wheel on the microswitch to
adjust the switch differential. Rotate clockwise to increase
the differential and counter clockwise to reduce the
differential.
2. Replace the instrument lid (see maintenance).
Switching Differential Adjustment: Model 723, 733, 773
(Fig 5)
1. Rotate the secondary adjuster knob to move the
secondary indicator along the ‘arrow’ scale. Rotate
clockwise to increase the differential and counter clockwise
to decrease the differential.
2. Replace instrument lid (see maintenance).
Note: For accurate setting, a suitable temperature gauge
should be used in conjunction with the above procedure.
Do not attempt to set the switch outside the scale limits.
Though the unit may be set anywhere within its operation
range, for optimum performance, it is good practice to
have a set point value between 25 % and 75 % of span.
REPLACEMENT PARTS
Use only factory authorised parts and procedures. The
only parts normally recommended for site replacement are
the microswitches. However, in some circumstances other
spares kits are available. Apply for details quoting the
serial number and full product code.
WARRANTIES – SEE CONDITIONS OF SALE
SENSING ELEMENT
MODELS 721, 722, 723, 771, 772, 773, 774, 781
SENSING ELEMENT
MODELS 731, 732, 733, 734
ISSUE H 02/10
INSTALLATION, OPERATING AND MAINTENANCE
INSTRUCTIONS FOR VAPOUR PRESSURE (MODELS
721, 722, 723, 731, 732, 733, 734, 781) AND GAS FILLED
(MODELS 771, 772, 773, 774) SERIES 700
TEMPERATURE SWITCHES
SPDT
NC=NORMALLY CLOSED
COM=COMMON
NO=NORMALLY OPEN 2 x SPDT
REAR (LO) FRONT (HI)
SW ITCH SW ITCH
FIG. 1
350 (13.7) MIN. 11 (.43) 25
(1)
R5.5
(0.21)
To remove lid on enclosures H, K, M l oosen and
rotate l id l ocki ng devi ce (refer to fig 8). Where lid is
tight use a flat bar, refer to recommended sizes
below. M ateri al needs to be hard chrome steel
spanner grade.
The edge of a spanner may be used.
All Dimensions m m (i nches)
Fig 1A
A D JU S TE R K N OB
LOC K IN G S C R E W
LO C K IN G P LA TE
S CA L E P LA TE
IN D IC A TO R
FIG . 2
LOCKING SCREW
(HIGH)
FRONT TOP VIEW
OF SWITCHING
MECHANISM
SCALE PLATE
(HIGH)
SCALE PLATE
(LOW)
INDICATOR
LOCKING SCREW
(HIGH)
LOCKINGSCREW
(LOW)
FIG. 3
ADJUSTING
SCREW
ADJUST SWITCHING
DIFFERENTIAL
FIG. 4
A D J U S T E R K N O B
L O C K IN G P L A T E
S E C O N D A R Y
A D J U S T E R K N O B
S C A L E P L A T E
S E C O N D A R Y
IN D I C A T O R
I N D IC A T O R
F I G . 5
2 LID RETAINING
SCREWS
(1.37)
M4 EARTH
SCREW
ELECTRICAL
ENTRY
FIXING CENTRES
FIXING
CRS.
* FOR ENCLOSURE N ADD 10mm. (0.39)
120
(4.72)
20
(0.78)
*35
51 (2)
10
(0.39)
70
(2.75)
41 (1.61)
95 (3.74)
154 (6.06)
174 (6.85)
7 (0.27)
7 (0.27)
77
(3.03)
Fig 6
FIXING CENTRES
.
(0.27)
(0.9)
45 (1.77)
103 (4)
77
(3.03)
7
174 (6.85)
154 (6.06)
53 (2)
35 (1.37)
70 (2.75) FIXING
SCREW
10
(0.39)
122 (4.8) APPROX.
23
ELECTRICAL
ENTRY
4 LID RETAINING SCREWS
M4 EARTH SCREW
Fig 7
( 0.9 8)
LI D L OC K M 4 SO CK ET C AP SCREW ( RO T ATE)
( 0.2 7)
M5 E ART H
CO NNECT IO N
E LE CT RI CA L ENT RY
F IXIN G CENT R ES
(1 .5 3)
7
1 4 (0 .55 )
3 9
15 6 ( 6. 14 ) 17 4 ( 6. 85 )
15 4 (6 .06 ) FI XING CRS.
8 3 (3 .3 )
25
1 96 ( 7.7 1) APP ROX.
11 3
(4 .4 4)
71 ( 2.7 9)
6 1 ( 2. 4)
Fig 8
140 (5.5) MODEL 771-4
(0.47)
BULB
SEMI-RIGID
EXTENSION
GLAND THREAD
ARMOURED
CAPILLARY
12 DIA
80 (3.14)
Fig 9
GL AND
T HREA D
D IA .
1 2 (0 .47 )
8 0 (
3 .1
4 ) B
U
L B
2 5 3 ( 9
.9
6 )
Fig 10
In the interest of development and improvement Delta Controls Ltd, reserve the right to amend without notice,
details contained in this publication. No legal liability will be accepted by Delta Controls Ltd, for any errors,
omissions or amendments.
YOUR TRUSTED PARTNER IN PROCESS INSTRUMENTATION
DELTA CONTROLS LIMITED, ISLAND FARM AVENUE, WEST MOLESEY, SURREY KT8 2UZ
T +44 (0) 208 939 3511 F +44 (0) 208 783 1163 E [email protected] W www.delta-controls.com
Stock No: 002522/720
Registered Office Registered in England No 5369683