Barksdale UNS-VA1 Level Switch Instruction Manual

: June 4, 2024
: Barksdale

Table of Contents

Barksdale UNS-VA1 Level Switch
Intended Applications
Safety Instructions
Standards
Warranty/Guaranty
Transport/Storage
Principle of Operation
Installation/Commissioning
Maintenance/Cleaning
- Maintenance
- Cleaning
Technical Data
Dimensions
References
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Barksdale UNS-VA1 Level Switch

Intended Applications

Barksdale level switches are approved exclusively for industrial applications. The level switches must not be used in situations in which human life depends on proper functioning of the device.

CAUTION

The level switches may only be used in the specified fields of application (see type label).
The temperature ranges must be within the permissible limits. The stated pressures and electrical load values must not be exceeded.
Observe the applicable national safety instructions for assembly, commissioning and operation of the level switches.

Every person installing, commissioning or operating Barksdale level switches must have read and understood these operating instructions.

Safety Instructions

The safety instructions are intended to protect the user from dangerous situations and/or material damage.
In the operating instructions the seriousness of the potential risk is designated by the following signal words:
DANGER
Refers to imminent danger to men. Nonobservance may result in fatal injuries.
WARNING
Refers to a recognizable danger. Nonobservance may result in fatal injuries, and destroy the equipment or plant parts.
CAUTION
Refers to a danger. Nonobservance may result in light injuries and material damage to the equipment and/or to the plant.
IMPORTANT
Refers to important information essential to the user.
Disposal
The equipment must be disposed of correctly in accordance with the local regulations for electric/electronic equipment. The equipment must not be disposed of with the household garbage!

Standards

The standards applied during development, manufacture and configuration are listed in the CE conformity and manufacturer’s declaration.

Warranty/Guaranty

Warranty
Our scope of delivery and services is governed by legal warranties and warranty periods.

Terms of guaranty
We guaranty for function and material of the level switches under normal operating and maintenance conditions in accordance with the statutory provisions.

Loss of guaranty
The agreed guaranty period will expire in case of:

changes or modifications to the switch/housing/fitting
incorrect use
incorrect installation or
incorrect handling or operation contrary to the provisions of these operating instructions No liability is assumed for any damage resulting therefrom, or any consequential damage.

Transport/Storage

CAUTION
Jolts and heavy vibrations must be avoided during transport. Storage should be dry and clean.

Principle of Operation

Cable
Stem
Float
Magnet
Reed switch

All Barksdale level switches work according to the principle shown in picture

A float equipped with magnets moves variably with the changing liquid level. The magnetic field of the float actuates a reed switch positioned inside the guide tube at a predefined place and closes or interrupts the current circuit. If several level switching points are arranged in the stem various alarm functions can be triggered. By adding suitable relays the signals can be used in control system or for automatic pump control. Advantages of these switching units: separation from the medium, no mechanical stress

Installation/Commissioning

IMPORTANT
All level switches are tested for proper functioning before they leave the factory.

DANGER
Prior to any work on electrical components disconnect them from power supply. The electrical connection may only be made by trained expert staff!

The Barksdale level switches are supplied completely assembled. The level switches are installed through the tank top or bottom side. Sufficient distance must be kept to the tank wall and any installations. The float must move freely. The Barksdale level switches should be installed vertically, if possible. Proper functioning is, however, guaranteed up to an inclination of 30°.

Contact Protection

The values for current, voltage and power stated on the type label apply to purely resistive loads.
Frequently, lamp loads or the like should be switched as well. In these cases protection of the reed switches against voltage and current peaks must be considered.
Below some examples are shown concerning the wiring of reed switches for various loads to avoid premature failure.

Inductive Loads

Direct current (DC): Connect recovery diode parallel to the load, see picture 4.
Polarity must ensure that the diode will inhibit at normal operating voltage and short-circuit the opposite voltage peaks occurring when opening the switch.
Alternating current (AC): Connect an RC unit parallel to the switch, see picture 5.
Dimensioning of such an RC unit can be executed according to the nomogram shown in the picture:

Capacitive Loads and Lamp Loads
Increased inrush currents occur for capacitive loads and lamp loads. High inrush currents can lead to disturbances – even to fusing of contacts. During wiring of charged capacitors (e.g. cable capacities) a sudden discharge will occur. The discharge intensity depends on the capacity and length of the supply cable to the switch to be regarded as series resistor. The discharge current peak is largely reduced by a series resistor. Its size is determined by the capabilities of the respective circuit. The series resistor should be as large as possible to limit the discharge current to a permissible value. These criteria apply analogously to the charging of capacitors, see picture 2.
Wiring lamp loads: The resistance value of cold lamp filaments (not switched on) is about ten times smaller than that of switched on lamp filaments. When the lamp is being switched on the current flow is for a short time ten times higher than in the glowing static state of the lamp. This tenfold inrush current can be reduced to a permissible value by a series-connected current limiting resistor. Parallel connection of a resistor to the switch is another option. The parallel resistor will permanently preheat the filament while the lamp is switched off just so far that it does not yet glow. Both protection systems result in the loss of power.

Use in Hazardous Locations
Type of protection “i” intrinsic safety
The level switches to be used in hazardous locations are principally designed for intrinsically safe circuits i following the applicable regulations and marked by the words Ex ia… on the type plate. They are only for use in an approved intrinsically safe circuit. The maximum values per circuit are stated on the type label.

Contact Wiring and Color Code

Temperature switches (TS or TP) and temperature sensors (PT100) are connected to the last contacts possible, unless otherwise specified.

CAUTION
Temperature switches (TS or TP) and temperature sensors (PT100) must be tested for functioning before commissioning.

Connection UTS 2000

CAUTION
The following notes must absolutely be observed:

The permissible data (see type label) must be kept.
The level switch must be protected against magnetic fields.
The sliding tube of the level switch must not be bent and severe shocks must be avoided, since otherwise the inert gas contacts (reed contacts) will be damaged.
Existing adjusting rings, gripping rings or clamping brackets must not be displaced since otherwise the SPST or SPDT function is no longer guaranteed.

The max. inrush power according to the data sheet is:

for level switch – SPST – with 12 mm or 13 mm sliding tube 100 VA
for level switch – SPDT – with 12 mm or 13 mm sliding tube 60 VA
for level switch – SPST – with an 8 mm thick sliding tube 40 VA
for level switch – SPST – with an 8 mm thick sliding tube 3 VA

These power values must not be exceeded since otherwise the switching contacts will fuse. A short circuit will immediately destroy the switching contact. Long cables take a high capacitive charging current during switching-on. This charging current can be limited by a current limiting resistor of about 20 to 30 Ohm <1.W>. The resistor is installed in the connecting housing of the level switch. Metal filament lamps take the three or four-fold of the current during switching-on. Level switches with a switching power of e. g. 100 VA can only switch 25 W filament lamps. This must be taken into account when a filament lamp is used for a continuity check. When switching direct voltages, a diode must be connected in parallel with inductive consumers, such as relays or solenoid valves, for spark suppression in locking direction. Cable glands of level switches must be checked for tightness at the connecting housing and at the level switch to ensure that no spray water can penetrate.. If necessary seal by means of filler.

Maintenance/Cleaning

WARNING
Check the level switch regularly for functioning. If the level switch does not work properly, stop operation immediately!

Maintenance

The level switch requires no maintenance.

Cleaning

CAUTION
Do not bend or hit the stem when cleaning the guide tube!

Proceed carefully to remove medium residues from the guide tube, if necessary.

Technical Data

Model| UNS-MS1/8-BN25 UNS-VA1/8- VA27| UNS-VA1/4- VA52| UNS-VA / SB4 (without test function)

UNS-VA / SB5 (with test function)

---|---|---|---
Installation position| from the top or from the bottom| on the side
Stem material| Brass

CrNi steel 1.4571

CrNi steel 1.4571

| CrNi steel 1.4571| Polyethylene PE
min. medium density [g/cm³]| BN25: 0.57

VA27: 0.71

| VA52: 0.78| 0.8
Max. permissible pressure [bar]| 15| 40| 3
Max. permissible temperature| 80/100 °C

105/150 °C, CrNi steel

5 VA/W / SPDT

| 100 VA/W SPST

60 VA/W / SPDT

UNS-VA/SB (with test function)

| UNS-PA16- PA18

UNS-PA1/2″NPT- PA18

| UNS-PP16- PP18

UNS-PP1/2″NPT- PA18

---|---|---|---
Installation position| on the side
Stem material| CrNi steel 1.4571| Polyamide 6.6| Polypropylene
Mounting material| Mounting traverse| M 16 x 2

1/2″ NPT, G1/2

60 VA/W / SPDT

| 60 VA/W|
Options| Test device| on request|
Approval| on request, see www.barksdale.de
Model| UNS1000| UNS2000
---|---|---
Installation position| from the top or from the bottom
Stem material| Brass, CrNi steel 1.4571
Mounting material| Flange and screw connection
Tightening torque| UNS1000-G (G1‘): 40 ±5 Nm|
Float| BN25, Ø = 25 mm; VA27, Ø = 27 mm| BN30, Ø = 30 mm; VA52, Ø = 52 mm
Float material| Buna N, CrNi steel 1.4571
min. medium density [g/cm³]| BN25: 0.57; VA27: 0.71| BN30: 0.60; VA52: 0.78
Max. permissible pressure [bar]| 15| 15, 40
Max. permissible temperature| 80/100 °C, NBR foamed 105/150 °C, CrNi steel| 80/100 °C, NBR foamed 105/150 °C, CrNi steel
Contact type| SPST (NO), SPST (NC), SPDT
Contact rating| 40 VA/W SPST; 5 VA/W / SPDT| 100 VA/W SPST; 60 VA/W / SPDT
Options| Hight-temperature version, temperature sensor
Approval| on request, see www.barksdale.de

Electrical contact rating for optional thermo-switch: 12 / 24 V DC, 3.0 A

CAUTION

The fittings and flanges must be conductively connected with the tank and integrated in the potential equalization system.
If various electrical components (e. g. reed switch and temperature switch) are used in a level switch, the electrical values of the weakest component must be observed.
No different potentials must be used.

Approval data for Ex i switches

For devices with connected cables, an additional capacitance of 200pF/m and an additional inductance of 1µH/m must be calculated.

Dimensions

Barksdale GmbH
Dorn-Assenheimer Straße 27 D-61203 Reichelsheim
Phone: +49 (6035) 949-0
Fax: +49 (6035) 949-111 and 949-113
email: info@barksdale.de
Internet: www.barksdale.de