Intrinsically Safe Drum Alarm

The Intrinsically Safe high level drum alarm responds to a high or low level condition, with a loud buzzer and flashing LED.  The buzzer is loud at 98dB measured at two feet, and since it has a unique warbling sound, it cuts through factory noise so it will be heard. The unit is rated for Class 1, Division I Hazardous Locations and, because it is battery powered, it can be placed in service instantly.

Easy to Install. Different drum mountings are all adjustable by hand. Simply loosen the nut or thumbscrew, and slide the alarm to the depth you want. Alternatively, we offer many choices of other drum mounts if preferred.

CONSTRUCTION

Durable construction from an aluminum electronics enclosure. Lexan LED lens, metal pushbutton. Where possible, the float switch is protected inside a float guard so it can be moved from drum-to-drum without worrying about damage.  The enclosure is waterproof to IP65.

BATTERY POWER

Battery Power is uninterruptible and allows installation anywhere. No outlets, electricians, or inspectors needed. The batteries are designed to last for many years. This is possible because we start with a lithium  battery that has a shelf life of 20 years. Also, the battery capacity is a remarkable 2400 mA-hr.  This, combined with firmware that puts them into a low output mode after 1 hour, allows these to sound for almost a month straight if unattended!   Of course this will never happen but its nice to know they can.  Furthermore, when the batteries do run low, a low-battery signal is given, which is different from the level alarm signal to make it easy to identify. Finally, the battery is easily replaceable in the hazardous location.

OPERATION

Different behaviors are field-selectable using DIP switches on the circuit board. For use on drums, the most popular would be the ability to enable or disable the 30-minute snooze alarm. If enabled, the LED continues to flash after the buzzer is silenced.  After 30 minutes, the buzzer will sound again until the level is corrected.  In addtion there are other behaviors available that are mostly related to the relay output.  More details on these are in the documents section below.

MODELS

There are models with a liquid feed pipe, (IS-DHP) or without a liquid feed pipe. (IS-DHK)  Since the IS-DHK models have no liquid feed pipe, they are able to fit into a 3/4″NPT drum bung.
In addition to feed pipe choice, there are different materials to choose from. To help with selection, here is a link to  chemical compatibility charts and a more detailed page of  float switch information

 316 Stainless Steel pipe and float. (model IS-DHK-SS)  Standard mount is a stainless “collar” with phenolic knob. Note: The diameter of the SS float is too large to surround the float with a float guard as we do with other float switches.

 316 Stainless steel pipe with BUNA float switch. (IS-DHK-SB)  In this case the float switch is protected with a Stainless steel float guard. Standard mount is a stainless “collar” with phenolic knob.  To help select, see this post on choosing a float switch To summarize, BUNA rubber is compatible with most oils, aliphatic hydrocarbons and fuels.  chemical compatibility chart here  

Polypropylene pipe and float switch. (IS-DHK-PP)  The float switch is protected with a float guard.