User manual HONEYWELL VCM DATASHEET

[. . . ] Furthermore, the stroke of the bellows is limited by an internal stop so that the forces resulting from the overpressure cannot be transmitted to the switching device. The parts of the sensor in contact with the medium are welded together without filler metals. Copper bellows, which are used only for low pressure ranges, are soldered to the sensor housing. The sensor housing and all parts of the sensor in contact with the medium can also be made entirely from stainless steel 1. 4571 (DNS series). [. . . ] These are not subject to testing or certification requirements within the meaning of Directive 94/9EC. The units may only be used in conjunction with ATEX-tested isolating amplifiers in areas at risk of explosion. We equip all units which are explicitly designed for such use with microswitches having gold contacts, a grounding screw and -- for ease of identification -- a blue cable entry. 22 Pressure switches Mechanical pressure switches General information about explosion protection Zone classification Explosion risk areas are grouped into zones according to the likelihood of a dangerous explosive atmosphere according to EN 1127-1 occurring. When assessing the explosion hazard, i. e. when identifying explosion risk areas, the "Guidelines for the Avoidance of Danger due to Explosive Atmospheres with Examples (ExRL)" of the German Insurance Association for the Chemical Industry [Berufsgenossenschaft Chemie] must be taken into account. If the situation concerns a special case or if doubts exist as to the definition of explosion risk areas, the matter shall be decided by the supervisory authorities (Trade Supervisory Office [Gewerbeaufsichtsamt], where applicable with the assistance of the Insurance Association or the Technical Control Boards [Technische Überwachungsvereine]). In Zones 0 (20) and 1 (21), only electrical equipment for which a type test certificate has been issued by a recognized testing agency may be used. In Zone 0 (20), however, only equipment expressly authorized for that zone may be used. Equipment approved for use in Zones 0 (20) and 1 (21) may also be used in Zone 2 (22). Under the new European Directive 94/9 EC (ATEX 100a), a distinction is made between gas atmospheres and dust atmospheres. This results in the following zone classifications: Zone 0 continuously or for long periods Zone 0 (gas) is a place in which a dangerous explosive atmosphere is present continuously or for long periods. This normally includes only the interior of containers or the interior of apparatus (evaporators, reaction vessels etc. ), if the conditions of Zone 0 are fulfilled. Zone 1 (gas) is a place in which a dangerous explosive atmosphere can be expected to occur occasionally in normal operation. This may include the immediate vicinity of Zone 0. Occasional danger = 10 to 1000 hours/year. Zone 2 (gas) is a place in which a dangerous explosive atmosphere can be expected to occur only rarely and then only for short periods. This may include areas surrounding Zones 0 and/or 1. Danger only under abnormal operating conditions < 10 hours/year. Zone 20 (dust) is a place in which a dangerous explosive atmosphere in the form of a cloud of dust in air is present continuously or for long periods, and in which dust deposits of unknown or excessive thickness may be formed. Dust deposits on their own do not form a Zone 20. Zone 21 (dust) is a place in which a dangerous explosive atmosphere in the form of a cloud of dust in air may occasionally occur in normal operation, and in which deposits or layers of inflammable dust may generally be present. This may also include the immediate vicinity of Zone 20. [. . . ] Switching differential Not adjustable with VCM and Ex-VCM types. Contact arrangement Single-pole changeover switch. Product Summary Type Setting range Switching differential (mean values) Max. permissible pressure Dimensioned drawing Switching differential not adjustable VCM 4156 -15. . . +6 mbar VCM 301 -250. . . +100 mbar VNM 301 ­250. . . +100 mbar VCM 101 ­1*. . . +0. 1 bar VCM 095 ­0. 9. . . +0. 5 bar VNM 111 ­1*. . . +0. 1 bar Switching differential adjustable VCM 301-203 ­250. . . +100 mbar VNM 301-203 ­250. . . +100 mbar VCM 101-203 ­1*. . . +0. 1 bar VCM 095-203 ­0. 9. . . . +0. 5 bar VNM 111-203 ­1*. . . +0. 1 bar 2 25 45 45 50 50 mbar mbar mbar mbar mbar mbar 1 1. 5 3 3 3 6 bar bar bar bar bar bar 1 1 1 1 1 1 + + + + + + 11 13 15 14 14 15 30­200 70 ­500 80 ­350 90 ­400 90 ­650 mbar mbar mbar mbar mbar 1. 5 3 3 3 6 bar bar bar bar bar 1 1 1 1 1 + + + + + 13 15 14 14 15 version, (housing 700), explosion protection EEx-d Ex-VCM 4156 ­15. . . +6 mbar 2 mbar Ex-VCM 301 ­250. . . +100 mbar 25 mbar Ex-VNM 301 ­250. . . +100 mbar 45 mbar Ex-VCM 101 ­1*. . . +0. 1 bar 45 mbar Ex-VCM 095 ­0. 9. . . +0. 5 bar 50 mbar Ex-VNM 111 ­1*. . . +0. 1 bar 50 mbar 1 1. 5 3 3 3 6 bar bar bar bar bar bar 3 3 3 3 3 3 + + + + + + 11 13 15 14 14 15 * At very high vacuums, close to the theoretical maximum of ­1 bar, the switch may not be usable in view of the special conditions of vacuum engineering. However, the pressure switch itself will not be damaged at maximum vacuum. [. . . ]