Engineered Systems

Recirculating Systems

RECIRCULATING SYSTEMS

In areas where a Haws tempering system is needed for a loop of safety equipment, a recirculating package can be added to provide warm or cool water at all points of use. A low flow pump with the necessary controls can be added to the system to allow the user of a safety shower an immediate supply of warm water.

FEATURES

Recirculating Pump: Haws can supply a complete 316 stainless steel end suction centrifugal pump. This pump is sized per the customer’s designed loop to deliver 5 to 10 GPM of warm water. The water leaves the booth at 80°F (26°C) and travels throughout the loop. As the water returns, it is reheated or recooled to 80°F (26°C).

Scalding Protection: Haws Model TWBS.SH offers two levels of protection to prevent scalding water from traveling to the showers. In the event the outlet temperature of the mixing valve reaches 85°F (29°C), the Hot-limit shutoff valve closes off the hot water supply and allows all flow to go through the cold side. This prevents the hot water from heating the outlet. Haws also supplies the customer with an aquastat. An aquastat is a temperature switch that senses the loop water temperature. Should the water reach 90°F (32°C), the switch will turn off the pump to allow the water to cool down by convection. This switch can also be wired to provide a high temperature alarm. Dry contacts are provided for remote alarming.

If the customer requires that the recirculation pump to be on at all times, Haws can add a solenoid switch which can be opened when temperature reaches 90°F (32°C). This will allow the hot water to dump to the drain and allow a supply of cold water to enter the loop.

If a low temperature alarm is needed, Haws can offer a second aquastat to sense the low end of water temperature. Again, this can be wired to a remote alarm with the use of dry contacts.

ADVANTAGES

A Haws tempering system with a recirculating package installed ensures an immediate supply of warm or cool water at any point in the safety equipment loop. This guarantees that the user will stay in the shower. A Haws recirculating package offers two levels of scalding protection to ensure a comfortable temperature of water at all times.

BOOSTER PUMP SYSTEMS

When a Haws tempering system is specified for a dedicated safety shower loop which has an insufficient water pressure, Haws can add a booster pump package to overcome the pressure loss. A booster pump with the necessary controls can be added to ensure proper flow at all showers that are connected to the system.

FEATURES

Booster Pump: Haws can supply an end suction, centrifugal pump that has been sized to provide the required flow to meet the ANSI standard. This pump can be sized to provide flow for a single shower or multiple showers.

Controls: The standard control for the booster pump is a flow switch. When flow is initiated through the tempering system, the flow switch will activate the booster pump. The pump pushes the water through the tempering system and out to the shower, or showers in use. This flow switch can be wired to a remote alarm with the use of a provided dry contact.

Options: In case of a power loss, a normally opened solenoid valve can be provided to bypass the tempering system. This allows cold water to bypass the loop and avoid the pressure drop in the tempering system, thus, providing a shower at all times. If a flow switch is not acceptable, the system can utilize a pressure-switching device. As the pressure drops in the system, the switch will recognize the loss of pressure and turn on the pump. With the use of a timer, the pump will remain on for 15 minutes even if flow is not needed for the duration.

If a backup pump is needed, Haws can add the second pump with the necessary controls to properly operate both pumps. In case of pump failure, the secondary pump will be automatically activated. After a period of time, the pumps will change from the lag pump to the lead pump to ensure proper function at all times. This is controlled with a programmable logic controller.

If there is an in-house standard for pumps, Haws can provide the make and model required on site, assuming that pump meets the needs and requirements for proper flow.

ADVANTAGES

In areas where there is not a sufficient potable water supply, a booster pump can be added to a Haws tempering system to provide the required flow at any shower in the loop. This ensures a proper flow at even the farthest showers. The booster pump unit eliminates the need for several tempering systems throughout the plant.

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