Armfield FT74P User manual

INSTRUCTION MANUAL
FT74P & FT74T
HTST/UHT
Heat Exchanger
Processing Units
FT74P & FT74T
ISSUE 13
MARCH 2002

ARMFIELD LIMITED
OPERATING INSTRUCTIONS
FT74P & FT74T - UHT HEAT EXCHANGER UNITS
PAGE NO.
SAFETY IN THE USE OF EQUIPMENT SUPPLIED BY ARMFIELD 1
INTRODUCTION 5
THE PROCESS 6
RECEIPT OF EQUIPMENT 8
DESCRIPTION 9
INSTALLATION REQUIREMENTS 23
ASSEMBLY 24
CONNECTION TO SERVICES 29
COMMISSIONING 31
OPERATIONAL PROCEDURES. 34
ROUTINE MAINTENANCE 42
CONNECTIONS TO THE I/O DATA PORT 55
GENERAL SAFETY RULES Appendix

SAFETY IN THE USE OF EQUIPMENT SUPPLIED BY ARMFIELD
Before proceeding to install, commission or operate the equipment described in this
instruction manual we wish to alert you to potential hazards so that they may be
avoided.
Although designed for safe operation, any laboratory equipment may involve
processes or procedures which are potentially hazardous. The major potential hazards
associated with this particular equipment are listed below.
•BURNS FROM COMPONENTS AT HIGH TEMPERATURES
•SCALDING FROM BOILING LIQUIDS OR HOT VAPOURS
•INJURY FROM PIPEWORK AND COMPONENTS AT HIGH PRESSURE
•INJURY FROM CORROSIVE LIQUIDS (CLEANING FLUIDS)
•INJURY THROUGH MISUSE
•INJURY FROM ELECTRIC SHOCK
•INJURY FROM HANDLING LARGE OR HEAVY COMPONENTS
•INJURY FROM ROTATING COMPONENTS
•DAMAGE TO CLOTHING
•RISK OF INFECTION THROUGH LACK OF CLEANLINESS
Accidents can be avoided provided that equipment is regularly maintained and
staff and students are made aware of potential hazards. A list of general safety rules
is included in this manual, to assist staff and students in this regard. The list is not
intended to be fully comprehensive but for guidance only.
Please refer to the notes overleaf regarding the Control of Substances Hazardous to
Health Regulations.
1

The COSHH Regulations
The Control of Substances Hazardous to Health Regulations (1988)
The COSHH regulations impose a duty on employers to protect employees and others
from substances used at work which may be hazardous to health. The regulations
require you to make an assessment of all operations which are liable to expose any
person to hazardous solids, liquids, dusts, vapours, gases or micro-organisms. You are
also required to introduce suitable procedures for handling these substances and keep
appropriate records.
Since the equipment supplied by Armfield Limited may involve the use of substances
which can be hazardous (for example, cleaning fluids used for maintenance or
chemicals used for particular demonstrations) it is essential that the laboratory
supervisor or some other person in authority is responsible for implementing the
COSHH regulations.
Parts of the above regulations are to ensure that the relevant Health and Safety Data
Sheets are available for all hazardous substances used in the laboratory. Any person
using a hazardous substance must be informed of the following:
Physical data about the substance
Any hazard from fire or explosion
Any hazard to health
Appropriate First Aid treatment
Any hazard from reaction with other substances
How to clean/dispose of spillage
Appropriate protective measures
Appropriate storage and handling
Although these regulations may not be applicable in your country, it is strongly
recommended that a similar approach be adopted for the protection of the students
operating the equipment. Local regulations must also be considered.
Water-Borne Infections
The equipment described in this instruction manual involves the use of water which
under certain conditions can create a health hazard due to infection by harmful micro-
organisms.
For example, the microscopic bacterium called Legionella pneumophila will feed on
any scale, rust, algae or sludge in water and will breed rapidly if the temperature of
water is between 20 and 45°C. Any water containing this bacterium which is sprayed
or splashed creating air-borne droplets can produce a form of pneumonia called
Legionnaires Disease which is potentially fatal.
Legionella is not the only harmful micro-organism which can infect water, but it
serves as a useful example of the need for cleanliness.
2

Under the COSHH regulations, the following precautions must be observed:-
Any water contained within the product must not be allowed to stagnate, ie. the water
must be changed regularly.
Any rust, sludge, scale or algae on which micro-organisms can feed must be removed
regularly, ie. the equipment must be cleaned regularly.
Where practicable the water should be maintained at a temperature below 20°C or
above 45°C. If this is not practicable then the water should be disinfected if it is safe
and appropriate to do so. Note that other hazards may exist in the handling of biocides
used to disinfect the water.
A scheme should be prepared for preventing or controlling the risk incorporating all
of the actions listed above.
Further details on preventing infection are contained in the publication “The Control
of Legionellosis including Legionnaires Disease” - Health and Safety Series booklet
HS (G) 70.
3

USE OF EARTH LEAKAGE CIRCUIT BREAKER AS AN ELECTRICAL
SAFETY DEVICE
The equipment described in this Instruction Manual operates from a mains voltage
electrical supply. The equipment is designed and manufactured in accordance with
appropriate regulations relating to the use of electricity. Similarly, it is assumed that
regulations applying to the operation of electrical equipment are observed by the end
user.
However, to give increased operator protection, Armfield Ltd have incorporated an
Earth Leakage Circuit Breaker (ELCB, alternatively called a Residual Current Circuit
Breaker or RCCB) as an integral part of this equipment. If through misuse or accident
the equipment becomes electrically dangerous, an ELCB will switch off the electrical
supply and reduce the severity of any electric shock received by an operator to a level
which, under normal circumstances, will not cause injury to that person.
At least once each month, check that the ELCB is operating correctly by pressing the
TEST button. The circuit breaker MUST trip when the button is pressed. Failure to
trip means that the operator is not protected and the equipment must be checked and
repaired by a competent electrician before it is used.
4

INTRODUCTION
The Armfield FT74 Miniature Heat Exchanger processing units have been designed to
allow small samples of food and other products to be processed conveniently in the
laboratory. Designed to mirror the industrial processes of HTST and UHT treatment
which are used to give increased shelf life to products, the FT74 will give product
with properties virtually identical to those processed in the factory.
This has been achieved by the development of miniature scale stainless steel heat
exchangers. The FT74P includes a plate heat exchanger made up of heat transfer
plates and gaskets, combined to form heating, regeneration and cooling heat
exchanger sections. The FT74T includes a number of tubular heat exchanger sections,
configured as pre-heat, heat and cooling heat exchanger sections.
The two different heat exchanger implementations are interchangeable with the
product processing (ie. the heat exchanger and the feed pump) being mounted on top
of a sealed stainless steel chassis. Within the chassis are compartments for the integral
hot water circulator, the electrical system, and the instrumentation and controls, all of
which are common to both systems. The circulator has been specifically designed to
provide efficient heating to the maximum product temperature of 150°C.
Although suitable for use in most production environments, the units are intended as a
means of “bringing the process into the laboratory” and can be used in relatively
small areas. A typical product throughput of only 10 litres per hour (variable from 0-
20 l/hr) allows testing using minimal quantities when small finished samples are
required. Also, start-up times are short, and rapid response of the temperature control
system enables samples of different products to be processed consecutively.
5

THE PROCESS
Holding Tube
Circulation
Pump
T4
4
Back Pressure Valve
Cooling
Section
Feed
Pump
P
T3
SSR
3 Term Controller
T1
Feed
Vessel
T2
Pressure
Relief Valve
Pressure
Relief Valve
Heating
Section
Cooling Water
Flow Control
Simplified Process Flow Diagram
(not showing pre-heat or re-generation stages)
The product to be processed is pumped from the Feed Vessel to the Heat Exchanger
by the Feed Pump. A Pressure Relief Valve protects the Heat Exchanger from
excessive pressure build up. Sensors measure the temperature and pressure of the
product before it enters the Heat Exchanger.
In the Heating Section of the Heat Exchanger the product is heated to the process
temperature by pressurised hot water. Note, for the purpose of simplicity, the above
diagram does not show the pre-heat section of the heat exchangers. The Plate Heat
Exchanger (FT74P) includes a re-generation stage, where the hot outgoing product is
used to pre-heat the incoming product. The Tubular Heat Exchanger (FT74T) uses
some of the pressurised hot water at a lower flow rate to pre-heat the product in a
dedicated pre-heat section. This is described in more detail in the Description section.
The pressurised hot water is generated by an electric heater contained in a heating
vessel. A pump circulates the hot water through the heat exchanger and back to the
pressurised heating vessel. A pressure relief valve provides protection against excess
pressure.
6

Each heat exchanger incorporates a Holding Tube between the final heating section
and the cooling section. The holding tube holds the product at the process temperature
for a defined time at the nominal process flow rate. A temperature sensor (T1)
measures the final product temperature at the end of the holding tube.
The sensor is used to control power to the hot water heater, by providing the control
input for a three-term controller. The output from the controller modulates the power
to the water heater via a solid state relay (SSR). In this way, the desired temperature
of product can be maintained.
The product is cooled in the cooling section of the heat exchanger, using a flow of
cold or chilled water. A combined flow meter and control valve is used to regulate
and measure the flow of cooling water.
A back-pressure valve at the product outlet from the heat exchanger is used to create a
pressure within the heat exchanger. This prevents the product boiling at the elevated
processing temperatures.
7

RECEIPT OF EQUIPMENT
1. SALES IN THE UNITED KINGDOM
The apparatus should be carefully unpacked and the components checked against the
Advice Note. A copy of the Advice Note is supplied with this instruction manual for
reference.
Any omissions or breakages should be notified to Armfield Ltd within three days of
receipt.
2. SALES OVERSEAS
The apparatus should be carefully unpacked and the components checked against the
Advice Note. A copy of the Advice Note is supplied with this instruction manual for
reference.
Any omissions or breakages should be notified immediately to the Insurance Agent
stated on the Insurance Certificate if the goods were insured by Armfield Ltd.
Your own insurers should be notified immediately if insurance was arranged by
yourselves.
8

DESCRIPTION
All numerical references relate to the various diagrams included in the text.
The major process components, (ie. the heat exchanger, the feed pump and the feed
vessel) are mounted on top of a self contained, mobile, stainless steel cabinet. Within
the cabinet are two compartments with sealed doors. The upper compartment (1)
contains the pressurised water vessel and pump. The lower compartment contains the
electrical tray (2), which is mounted on slides for easy access. At the front of the
cabinet, a washable flat panel (3) provides the major control and display functions.
PROCESS ASSEMBLY
Two variable speed feed pump options are available with the FT74. The FT74-19 is a
gear pump, (4) which enables relatively high operating pressures to be achieved (up to
10.0 bar) at low product throughput (10-20 l/h) and is capable of the higher flow-rates
required when cleaning in place. However the use of a gear pump means that the
product throughput varies with applied back pressure. The FT74-18 is a progressive
cavity (Screw type) pump, which provides a very stable flow regardless of back
pressure changes. However the maximum flow achievable for clean in place is
reduced from that achievable with the gear pump.
The feed tank (5) is a 5.0 litre stainless steel open topped vessel.
The back-pressure valve (9) at the outlet from the heat exchanger is used to create a
pressure within the heat exchanger which prevents boiling of product at the elevated
processing temperatures. Turning the handle of the valve clockwise increases system
pressure and anti-clockwise reduces system pressure.
A pressure safety valve (7) protects the system from over pressure in the event of a
blockage or too high a setting of valve (9). A pressure transducer situated in the
pipeline between the feed pump and the heat exchanger measures the actual feed line
pressure for display on the control panel.
The process temperatures are measured by stainless steel semi-conductor temperature
sensors.
9

9
5
7
3
FT74T
10

9
5
3
FT74P
11

5
1
2
4
FT74P (Rear View)
12

PLATE HEAT EXCHANGER PROCESSING ASSEMBLY OPTION (FT74-30)
This heat exchanger option is configured as a conventional three stage plate heat
exchanger. The three sections (A), (B) and (C) are mounted together on the same
framework.
Section (A) is the interchange or regeneration section, section (B) is the heating
section and section (C) is the cooling section.
C A B
Holding
Tube
Product
Out
Cold Water
Circulation Product
Feed
Hot Water
Circulation
The cold, unprocessed product enters the interchange section (A), where it is
preheated by the outgoing product from the heating section. After preheat, the product
enters the heating section (B) where it is heated to the desired processing temperature
as measured by temperature sensor (T1).
After leaving (T1), the product re-enters the heat exchanger section (A) where it flows
counter-currently to the in-going product, giving up heat and becoming pre-cooled
before entering section (C) for final cooling using cold or chilled water.
13

TUBULAR HEAT EXCHANGER PROCESSING ASSEMBLY OPTION (FT74-
20)
T1
Tubular Heat Exchanger
(FT74-20)
6
The tubular heat exchanger accessory comprises a number
of sections of dual concentric tubes. In each tube, the
product flows through the centre of each tube section,
whilst the heating (or cooling) water flows through the
outer tube.
The pre-heat tubes allow the initial heating of the product to
be more gentle, by restricting the flow of the hot water. A
needle valve (6) provides precise control of the amount of hot water flowing through
this section.
Water
Product
The main heating tubes have full flow of the heating water to allow the process fluid
to be heated to the desired processing temperature as measured by temperature sensor
(T1).
The cooling tubes use cold or chilled water in the outer jacket to reduce the
temperature of the product once it has been processed.
14

All the tube sections are of similar stainless steel construction. The tube sections are
joined together with 'U’ shaped stainless steel pipes, connected to the heat exchanger
tube sections by hygienic tri-clamp stainless steel fittings. These fittings allow easy
access to the individual tube sections for inspection and cleaning.
Flexible hoses connect the heat exchanger to the hot and cold water systems. Again,
tri-clamp fittings are used for ease of changing the heat exchangers.
T1
T2
T3
Pressurised
Hot Water
Product Out
4 Coolin
g
Tubes
4 Heating Tubes
2Pre
-
Heat Tubes
Product In
15

FILL &
LEVEL
FEED
HOT WATER SYSTEM
The hot water reservoir is located in a frame in the main compartment of the cabinet.
15 P1 T1 T2 T3
PUMP
OUTLET
RCCB MAIN OUTLET D.C. HEATER H.W.PUMP FEED PUMP
DATA
LOGGING
12
17
16
11
10
20
18
A magnetically driven gear pump (10) is used to circulate the heated water from the
reservoir (11) to the heat exchanger.
The reservoir operates with approximately 4.0 litres of softened water. The reservoir
is filled using the level plug (12). In normal operation, the water will only need to be
replenished on the occasions when the heat exchanger is dismantled (and small
quantities of water are lost subsequently). However, if over-heating occurs, water
could also be lost through the pressure relief valve.
If the water level is low for any reason, a low level switch ensures that no power is
allowed to the electrical heating element or the circulating pump (10). In these
circumstances a warning lamp on the console is illuminated.
High temperature hoses attached to the pump head and to the reservoir (11) carry the
water to the process and return from the process respectively. A connecting pipe
provides the suction to the pump from the reservoir.
16