Griswold Filtration & PEP Filters
Griswold Separators and Filtration Systems provide a means to remove solids from flowing liquid through the use of centrifugal forces and sand beds. 
Typical applications include condenser water systems, water treatment, irrigation, oil recycling, steel mills, chemical process and power plants.
Our most common applications are cooling tower systems. Solids left in the condenser water can build up and promote scale causing in-efficiencies. Removing the solids from the condenser water will promote an efficient chiller system.
GrisWold Dual-Stage Separators
First Stage
The solid-laden stream enters the separator tangentially through a parabolic design velocity accelerator pad. The pad is designed to instantaneously accelerate the fluid to 3.5 times the inlet velocity, immediately creating a strong centrifugal force on the solids content. The following details the first stage of solids separation;
- Diffuser vanes collect saturated air and bubbles
- Pressure relief once the collected air reaches the relief valve setting
- System stream is directed by the spiral ring
- Concave top spin plate deflects solids that may enter the vortex region and shortens the travel of the vortex with much cleaner liquid
- Decelerated solids are trapped by opposing vanes
- Solids pass through a gap between the bottom spin plate and the inner wall of the separator
- Bottom spin arrestors ensure fluids will not flow back upward
Second Stage
The second stage starts at the entry to the discharge nozzle when a choke ring impedes the encirculating smaller solids. A venturi effect is created in 2 opposite nozzles angled in the direction of flow drawing the solids to a vacuum chamber and releasing them back into the main stream.
Solids Management
Once the separator has removed the solids from the fluid stream, the next step is to remove the solids from the system all together. 3 common purging options are available and at least one is required on all separator systems.
- The simplest purge is a manual purge valve.
- An auto purge can be set up to dump the solids from the separator on a timed or building management initiated signal.
- A closed recovery system can be included to collect the solids in a recovery vessel. A pressure annunciator package can be installed to indicate when the vessel filter bag is full.
Sand Filters
For increased filtration, Griswold manufactures sand filters. Fluid enters the upper body in a rotational direction, enabling the dirt/contaminants to continuously rotate with the water. This prevents the solids from blanketing the top of the media, keeping it fluidized at all times. Since fluids are not agglomerated, the filtration cycle is longer, and the backwash cycle is shorter for economical operation.