How Do Urinal Cisterns Work?

How Do Urinal Cisterns Work?

While urinals only deal with liquid waste, it’s still of paramount importance to have them flushed regularly with fresh water. Urine can leave salt deposits and a build-up of Uric acid, and not only leaves a foul smell behind but can begin to clog up your waste pipes. 

Urinal cisterns hold a volume of water that is used to flush around the urinal bowls and leave them rinsed, clean, and ready for the next user.  

How do urinal cisterns work?

Traditional urinal flushing systems have a tank of water positioned above the urinals. When the water level in the cistern reaches a set limit the water will flow from the cistern, through the flush pipes, out of the urinal spreader, and into the urinal bowls.  The water then flows through the urinal waste, into the trap, and out to the sewer via the urinal waste pipe.

Cistermiser Standard Hydraulic Urinal Flush Control Valve

Hydraulic Pressure 

Products such as the Cistermiser standard urinal flush control valve will allow water to fill into the urinal cistern when the washroom is in use.  The Cistermiser device is installed "in-line" with the water supply inlet pipe into the cistern and senses short-term drops in pressure within the water supply system. Each time a drop in pressure is identified the valve releases a measured amount of water into the cistern. The auto-syphon will flush the urinals once the required amount of water is in the cistern. The short-term drops in water pressure are caused by the use of taps or toilet flushing within the washroom, which approximates the use of the urinals.  

Infra-red Urinal flushing devices

Other more sophisticated devices use infra-red technology to fill and flush the urinal cistern.  The urinal sensor is connected to a solenoid valve that is plumbed directly into the urinal water feed pipe. The infra-red sensor detects movement within the vicinity of the urinals and subsequently allows a small amount of water to fill the urinal cistern. The more movement that is detected, the quicker the urinal cistern is filled before reaching its limit and flushing the urinals.  Take a look at the Dudley Kinetic Infrared Urinal Flush Control which can be wall-mounted or ceiling-mounted and is WRAS approved.

Dudley Kinetic Infrared Urinal Flush Control

Traditionally, urinal cisterns and urinal bowls would be wall-mounted with all of the associated water feed and waste pipes on show, but today many are concealed within a false wall or DUCT system.  Concealed urinal cisterns keep the room looking clean and modern, but also keep the pipework protected. 

Direct urinal Sensor Flush Kit

Mains fed flushing

Mains fed systems remove the need for a cistern. Instead, they have a copper pipe connecting directly into the back of the urinal, bypassing the need for a conventional cistern.  A solenoid valve is fitted into the copper pipe which opens and closes on demand to allow water to flow into the urinal bowl.  The solenoid valve is controlled by a panel-mounted bezel which is initiated when a user stands in front of the sensor.  The solenoid valve opens up for a set period of time to allow water to pass through and flush the urinal bowl clean. 

The solenoid valves need to be connected to mains electricity or can be powered via a battery. Most models offer adjustments to flow time and also deliver a pre-flush, cleaning the inside of the urinal when someone approaches to use it. 

Armitage Shanks Sphero Urinals

If you're considering a direct feed urinal system you may wish to consider Armitage Shanks Spehro MaxiThe smart sensor technology detects salinity and urinal use, activating flushes and using water only when needed.  This Hybrid revolution can save over 50,000L of water per year in high-traffic environments compared to infrared solutions.  If the sensor detects a blockage or a cartridge or battery end of life, the spreader light will provide a distinctive warning alert for corrective maintenance.  When a blockage is detected no more flushes will be triggered. 

If you would like further advice regarding urinal flushing options, or to speak with one of the team regarding any washroom refurbishment works, please get in touch on 01202 650900.

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