Leak Detection

Help With a System



How to Specify
a Delphian System

Detailed Steps


A. Select sensors by gas to be detected. Sensors are available for combustible hydrocarbons, hydrogen, hydrogen sulfide (both electrochemical and solid state), carbon monoxide, mercaptan, nitrogen dioxide, oxygen and sulfur dioxide.
Select one sensor for each point (location) to be monitored. The 365-xxx are the replaceable element CommonSensors. They are available either in Aluminum or in Stainless Steel. Disposable sensors are available for some gases.
If a combustible hydrocarbon sensor is being selected and the environment is especially problematic, consider selecting a poison resistant sensor. 
B. If the atmosphere is dusty, select dust covers. If the atmosphere is wet or windy, select splash guards.
If the sensor is to be mounted in a duct with a flow rate higher than 0.07 CFM (cubic feet per minute) 2 LPM (liters per minute) or if the temperature of the air exceeds the operating temperature of the sensor, the reclamation adaptor should be selected. Ported adaptors should be selected for remotely applying gas (for calibration) a sensor located in an inaccessible location.
One flame arrestor tool should be purchased if the flame arrestor on the sensor is likely to get clogged with dust or particles and will need to be cleaned on site or replaced.
Delphian does NOT recommend on site replacement of the sensor element in the combustible sensor as the elements are extremely fragile and damage during replacement will void the warranty. Delphian recommends that element replacement be performed by Delphian personnel (labor will not be charged) for guaranteed success.   

A. Select a transmitter (by gas), one for each sensor.
B. Each transmitter requires an explosion proof housing (conduit box). The SafeCAL requires a different housing.
Choose the housing appropriate for the approval required: CSA, FMRC. or BASEEFA. Transmitter housings ordered as spares will have no approval label. All housings are rated for groups ABCD (FMRC); BCD (CSA). BASEEFA housings are Zone 1, Group IIB.
C. If one person remote calibration is required there is a choice:
i. Analog remote calibration module which requires the conduit box to be opened during calibration. If this option is selected a remote calibration module for each transmitter (a 1-5mA module for controller based systems, or a 4-20 mA module for standalone systems) is needed plus a remote calibration meter per system. The remote calibration module fits in the same housing.
ii. Digital remote calibration module: SafeCAL. This option is programmed at the factory, uses a magnet for calibration and does not require opening the conduit box. It has a digital readout of gas concentration at the sense point. See back page for configuring a SafeCAL system.
D. Consider lightning arrestors to protect transmitters? Each arrestor protects one transmitter and requires its own explosion proof housing.
E. Consider an RFI filter with electrochemical sensors to reduce noise produced from EMI and RFI.
F. The transmitter may need to be separated from the sensor. (The electrochemical sensors put out too low a current to be separated from their transmitter but it is possible with the other sensors). If it does, select (from sensor accessories) the sensor extension kit  (this kit includes a housing, terminal block and connectors for user supplied wiring to separate transmitter and sensor for up to 100 ft) or sensor extension cord (this is wire with gold plug-in connectors) in lengths up to 72 inches. If the sensor is more than a few feet from the transmitter, also select the ported adaptor for easy calibration.

Decide on the kind of control system that you need. Delphian offers controllers mounted in a Flexirack, and a sophisticated computerized plant-wide control system (The Sage) which offers digitized speech activated calibration, soft wiring of relays and documentation of events. If the system that you are specifying will have 32 points or more, consider the Sage. See the page 6 for information on configuring the Sage.
To choose a Delphian controller:
A. Select the controller (by gas to be sensed). Two controller types are available:
(a) Digital Controller (accepts 1-5mA or 4-20 mA input) - this is a double unit, one controller for each of two sensor points. Each controller takes two slots in a Flexirack. A configuration form should be filled out for each sensor point or gas type.
(b) Analog Controller (accepts 1-5mA input only) single unit, one controller, takes up one slot in a Flexirack.
B. Decide if Zone Alarm Modules (ZAMs) are needed.
i. The CAM provides a single relay contact transfer whenever any one alarm occurs in a rack.
ii. The SAM functions like a CAM but each alarm can be sequentially acknowledged.
iii. The VAM provides a single relay contact transfer when a specified minimum number of individual alarms occur in a rack.
C. Are lightning arrestors required to protect the controllers? (one per controller, not required for ZAMs) Each arrestor needs its own explosion proof housing.

If you have chosen controllers, select the Flexirack mounting
A. Decide between rack/panel mount, panel mount, or enclosure/wall mount Flexirack. The 19" rack mount is a 16 slot flexirack.The panel/rack mount is available from 2 to 16 slots. The wall/enclosure mount is available in from 2 to 16 slots and is most often selected to be installed in a NEMA 4X or NEMA 7 enclosure.
B. Count the number of sensors and zone alarm modules. Add any blank spaces required for future expansion in enclosure or Flexirack. These are the number of slots required in the Flexirack, and represents the two numbers before the x in the Flexirack part number. The x indicates the number of slots on the right end of the Flexirack which are designated ZAM slots. At a minimum this number must equal the number of ZAMs purchased with the system. (For example 364-197-082 is an 8 channel panel mount Flexirack with 6 controller slots and 2 ZAM slots). Add blank (black) front panels for each slot designated for future expansion.

Select a power supply
, based on the number of Flexirack slots. (Each controller channel requires 0.4 amps for combustible catalytic sensors and solid state hydrogen sulfide sensors, 0.1 amp for electrochemical sensors, 0.2 amps for infrared sensors and each ZAM 0.2 amps.)
There are three types of Delphian power supplies. All are regulated.
i. Supplies which convert AC (switchable to 117 or 240) to the 24 VDC required by the Delphian system. (The standard choice).
ii. Supplies which convert 12 VDC to 24 VDC.
iii. Supplies which not only convert AC to DC but incorporate a battery charging system (trickle charger, circuit breakers, output meters) for a battery back-up. These power supplies come standard in NEMA 12 enclosures so separate enclosures need not be selected. Delphian will custom design a battery backup system for your application. Batteries should only be in NEMA 12 vented enclosures. However, the power supply/charger can be incorporated into any enclosure type. If more than 220 Amp Hours are needed, select a second battery set.
If the user supplies power, we suggest regulated or full wave rectified with 1% ripple, although the system can accept unregulated power.

A. Select a protective enclosure for flexirack/controller configuration. The Flexirack configurations are intended to be installed in a control room environment. If this is not the case, a wide variety of enclosures are available: NEMA 12 to protect against dust, NEMA 4x against water and corrosion, and NEMA 7 (Class I, Div 1, C&D) against explosive atmospheres. Wall mount Flexiracks are used with the NEMA 4x and NEMA 7 enclosures (except for the special 2 channel NEMA 7), Panel mount Flexiracks are used with NEMA 12 enclosures. All sizes in price sheet are HxWxD in inches. Enclosures are intended to accommodate the number of controllers specified and the appropriate power supply. A larger enclosure may need to be chosen to accommodate a telephone dialer or annunciator panel in the same enclosure or a power supply/battery back up system.
NOTE: Delphian will custom design an enclosure for your application.
B. Select options and accessories for the enclosure chosen. For NEMA 4x and NEMA 12 the system accessories in step 7 may also be selected.

Select accessory items for the system. Don’t forget owners manuals. One owner’s manual will be provided with each system for each gas. Most owners need several copies. The SafeCAL and Determinator have separate operations manuals which cover these modules. Select tags and specify engraving if required.

Don’t forget to specify spare parts. These should include transmitters, sensors, flame arrestors and flame arrestor sensor tools, remote calibration modules and meters, calibration screwdrivers.

Your system will need to be calibrated regularly
A. Select a calibration system for each gas to be monitored. Some gases can be calibrated by a flow method;others are considered too dangerous to use this method and a static system is provided for them.
Flow calibration kits (which supply gas by flowing it over the sensor) are of two types. Type A includes everything (a sensor gas connector with tubing, a pressure and flow regulator assembly and a calibration screwdriver), except the gas cylinder, needed to calibrate a sensor and comes in a carrying case which can hold one or two cylinders of calibration gas. Type B does not include the carrying case. In each instance, A or B, the appropriate gas must be ordered with the Kit. These gases are offered in 105 liter cylinders and provide approximately 75 calibrations.
Zero calibration: If there is a background gas, a cylinder of zero air and a calibration kit should be selected so that a true zero calibration can occur. This is especially important for toxic gases such as hydrogen sulfide where a large background can exist without the calibrator’s knowledge. The infrared sensors require zero air for re-zeroing.
Static calibration systems come in one kit form, Type C, which includes a calibration chamber, a gas calibration gauge and valve assembly and a calibration screwdriver. You must select the gas to be used separately. These gas cylinders are 36 liters and provide approximately 400 calibrations.

Copyright 2024 Delphian Corporation,  Northvale, N.J., U.S.A.