WIKA APA10 User Manual

NI-205E

INSTRUCTION MANUAL

Rev. 1 12/02

ABSOLUTE PRESSURE SWITCHES

WEATHERPROOF: SERIES APW EXPLOSIONPROOF: SERIES APA

Models APWH, APWL

Models APAH, APAL

A pressure attachment B cable entry Models APW10

WEIGHT 5,5 kg (dimensions in mm)

A vacuum attachment B cable entry Models APA10

WEIGHT 6,5 kg (dimensions in mm)

A pressure attachment B cable entry

NOTE: dimensions and weights are not binding unless released on certified drawings. CAUTION

• Before installing, using or carrying out maintenance on the instrument it is necessary to read and understand the indications given in the attached Instruction Manual.

• The instrument must only be installed and maintained by qualified personnel.

• INSTALLATION IS TO BE CARRIED OUT ONLY AFTER CHECKING THAT INSTRUMENT CHARACTERISTICS

ARE CONSISTENT WITH PROCESS AND PLANT REQUIREMENTS

• The functional features of the instrument and its degree of protection are shown on the identification plate fixed to the case.

SAFETY INSTRUCTIONS FOR USE IN HAZARDOUS ATMOSPHERES. RECOMMENDATIONS FOR PRESSURE SWITCH SAFE USE.

All data, statements and recommendations supplied with this manual are based on information believed by us to be reliable. As

the conditions of effective use are beyond our control, our products are sold under the condition that the user himself evaluates such conditions before following our recommendations for the purpose or use foreseen by him.

The present document is the property of ETTORE CELLA SPA and may not be reproduced in any form, nor used for any purpose other than that for which it is supplied.

WEIGHT 8,2 kg (dimensions in mm)

A vacuum attachment B cable entry

WEIGHT 10 kg (dimensions in mm)

RELATED DOCUMENT

To authentified document with certificate

N° CESI 03 ATEX 004

INSTRUCTION MANUAL

1. GENERAL NOTES

1.1 FOREWORD

APW and APA series were designed for applications where absolute-zero rather than atmospheric set point value is required (see fig.1)

Fig. 1 -

Pressure designation

NI-205E

Rev. 1 12/02

1.5 TEMPERATURE

Due to the temperature of both the environment and the process fluid, the temperature of the instrument could exceed the allowed limits (normally from -20° to +70°C). Therefore, in case it does, suitable measures (protection against heat radiation, fluid separators, cooling coils, heated lockers) must be taken. Process fluid or its solid particles must not however go inside instrument chambers.

2. OPERATING PRINCIPLE

The process pressure, acting on the diaphragm sensitive element, that has got absolute vacuum as reference pressure, determines its elastic deformation which is used to activate one or two electric microswitches regulated at set point values. The microswitches are of the rapid release type with automatic rearm. When the pressure moves away from the set values, returning towards the normal values, the switch is rearmed. The differential gap (difference between the set point value and the reset value) can be set or adjustable (letter R in the contact codes).

3. IDENTIFICATION PLATE AND MARKINGS

The instrument is fitted with a metal plate bearing all its functional characteristics and – in case of explosionproof execution (Series APA) – also the markings prescribed by standard CEI EN 50014. Fig. 2 shows the plate mounted on explosionproof instruments.

Fig. 2 - Explosionproof instruments plate

1.2 RANGE CHOICE

The wrong choice of a series or a model, as well as the incorrect installation, lead to malfunction and reduce instrument life. Failure to abide by the indications given in this manual can cause damage to the instrument, the environment and persons.

1.3 ALLOWED OVERRANGE

Pressure exceeding the working range can be occasionally tolerated provided they remain within the limits stated in the instrument features (vacuum or proof pressure). Continuous pressures exceeding the working range can be applied to the instrument provided they are clearly stated in the instrument features. The current and voltage values stated in the technical specifications and ratings must not be exceeded. Transitory overranges can have a destructive effect on the switch.

1.4 MECHANICAL VIBRATIONS

Can generally lead to the wearing of some parts of the instrument or cause false actuation. It is therefore recommended that the instrument be installed in a place where there are no vibrations. In cases where this is impossible it is a good idea to take measures to lessen the effects (elastic supports, installation with the peg of the microswitch positioned at right angles to the vibration plane, etc.).

1 CE marking and identifi cation number of the notified body

responsible for production surveillance.

2 Apparatus classification according to ATEX 94/9 CE

directive.

3 Type of protection and ambient temperature limits of

operation.

4 Notified body that issued t he type certi ficat e and number of

said certificate.

4. SET POINT REGULATION

Each microswitch is independent and can be regulated by means of a screw (for adjustment) in such a way that it is released when the pressure reaches (increasing or decreasing) the desired value (set point). The instrument is usually supplied with the switches set at the setting range value nearest to zero (factory calibration). The instrument is supplied with an adhesive rating plate showing the set point calibration value. With factory calibration the values are not indicated on the ratings as these are temporary and will be modified with the definitive values. Prior to installation the instrument must be calibrated and the definitive calibration values written on the adhesive rating plate using a suitable indelible ink pen.

If the instrument has been ordered with a specific calibration, it is a good rule to check the calibration values marked on the relevant adhesive label, prior to installation.

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