Abstract: An underdrain filter block for use in draining and backwashing a filtering media in a filter bed including a top wall, a pair of side walls extending from the top wall, a bottom wall extending between the pair of side walls, and a transverse wall extending from one of the pair of side walls to the other of the pair of side walls. The top wall, the pair of side walls, and the bottom wall define an upper portion and a lower portion. The lower portion includes a grout chamber positioned between the bottom wall and the transverse wall and at least one of the bottom wall and said side walls contains an opening.

Abstract: An underdrain filter block includes a top wall, a pair of side walls extending from the top wall, a bottom wall extending between the pair of side walls, first and second ribs, and a wall segment extending between the first rib and the second rib to define a grout chamber configured to receive grout during installation of the underdrain filter block.

Abstract: An underdrain filter block for use in draining and backwashing a filtering media in a filter bed including a top wall, a pair of side walls extending from the top wall, a bottom wall extending between the pair of side walls, and a transverse wall extending from one of the pair of side walls to the other of the pair of side walls. The top wall, the pair of side walls, and the bottom wall define an upper portion and a lower portion. The lower portion includes a grout chamber positioned between the bottom wall and the transverse wall and at least one of the bottom wall and said side walls contains an opening.

Abstract: An underdrain flume plate for use in a filter including at least one central opening having an upstanding flange to interface with a cut-out in an underdrain lateral to form a passageway for connecting the lateral to the flume. The flume plate may also include at least one raised channel at each end of the plate with a solid or cut-away top surface, and/or holes and/or slots for connection of the flume plate to anchor rods and may be configured to overlap one another when placed side by side. The present invention also includes a method of installing underdrain laterals in a filter, including arranging a grid of anchor rods on a filter floor such that anchor rods are provided on both sides of the flume, and providing at least one underdrain flume plate adapted for attachment to the anchor rods such that the flume plate covers the flume.

Abstract: An underdrain filter block includes a top wall, a pair of side walls extending from the top wall, a bottom wall extending between the pair of side walls, first and second ribs, and a wall segment extending between the first rib and the second rib to define a grout chamber configured to receive grout during installation of the underdrain filter block.

Abstract: An underdrain filter block for use in draining and backwashing a filtering media in a filter bed includes a top wall, a pair of side walls extending from the top wall, a bottom wall extending between the pair of side walls, and a transverse wall extending from one of the pair of side walls to the other of the pair of side walls. The top wall, the pair of side walls, and the bottom wall define an upper portion and a lower portion. The lower portion includes a grout chamber positioned between the bottom wall and the transverse wall and at least one of the bottom wall and said side walls contains an opening.

Abstract: An underdrain block including a top wall, a bottom wall, and a pair of sidewalls defining a hollow interior and having a longitudinal axis, wherein the sidewalls, top wall, or both comprise at least one external detail. A handle is detachably connected to the external detail for transportation and positioning of said underdrain block. The external detail may comprise one of a protrusion or a receptacle for receiving a protrusion and the handle may include the other of a protrusion or a receptacle for receiving a protrusion. Also, a method of installing an underdrain block lateral comprising at least one underdrain block including the steps of attaching a handle to external details on the underdrain block, lifting the underdrain block lateral by the handle, positioning the underdrain block lateral into the underdrain system, and detaching the handle from the external details of the underdrain block.

Abstract: An underdrain filter block for use in draining and backwashing a filtering media in a filter bed includes a top wall, a pair of side walls extending from the top wall, and a bottom wall extending between the pair of side walls. The top wall, the pair of side walls, and the bottom wall define an upper portion and a lower portion. The lower portion includes a grout chamber having a plurality of openings defined by at least one of the bottom wall and the pair of side walls.

Abstract: An underdrain filter block for use in draining and backwashing a filtering media in a filter bed includes a top wall, a pair of side walls extending from the top wall, a bottom wall extending between the pair of side walls, and a transverse wall extending from one of the pair of side walls to the other of the pair of side walls. The top wall, the pair of side walls, and the bottom wall define an upper portion and a lower portion. The lower portion includes a grout chamber positioned between the bottom wall and the transverse wall and at least one of the bottom wall and said side walls contains an opening.

Abstract: An underdrain flume plate for use in a filter including at least one central opening having an upstanding flange to interface with a cut-out in an underdrain lateral to form a passageway for connecting the lateral to the flume. The flume plate may also include at least one raised channel at each end of the plate with a solid or cut-away top surface, and/or holes and/or slots for connection of the flume plate to anchor rods and may be configured to overlap one another when placed side by side. The present invention also includes a method of installing underdrain laterals in a filter, including arranging a grid of anchor rods on a filter floor such that anchor rods are provided on both sides of the flume, and providing at least one underdrain flume plate adapted for attachment to the anchor rods such that the flume plate covers the flume.

Abstract: An underdrain block including a top wall, a bottom wall, and a pair of sidewalls defining a hollow interior and having a longitudinal axis, wherein the sidewalls, top wall, or both comprise at least one external detail. A handle is detachably connected to the external detail for transportation and positioning of said underdrain block. The external detail may comprise one of a protrusion or a receptacle for receiving a protrusion and the handle may include the other of a protrusion or a receptacle for receiving a protrusion. Also, a method of installing an underdrain block lateral comprising at least one underdrain block including the steps of attaching a handle to external details on the underdrain block, lifting the underdrain block lateral by the handle, positioning the underdrain block lateral into the underdrain system, and detaching the handle from the external details of the underdrain block.

Abstract: An underdrain filter block for use in draining and backwashing a filtering media in a filter bed includes a top wall, a pair of side walls extending from the top wall, and a bottom wall extending between the pair of side walls. The top wall, the pair of side walls, and the bottom wall define an upper portion and a lower portion. The lower portion includes a grout chamber having a plurality of openings defined by at least one of the bottom wall and the pair of side walls.

Abstract: A testing module for use with a gas detector, includes a plurality of gas inlets and outlets, each outlet being in fluid connection with one of the inlets. Each of the outlets is adapted to mate with and form a fluid connection with one of the inlets of a second like testing module. Gases can then flow from the outlets of the testing module into the inlets of the second like testing module. A gas container module for use with a gas container, includes a plurality of gas inlets and outlets, each inlet being in fluid connection with one of the outlets. Each of the inlets is adapted to mate with and form a fluid connection with one of a the outlets on a second like gas container module. Gases can then flow from the outlets of the second like gas container module into the inlets of the gas container module.

Abstract: A photoionization detector includes a housing, electrical contacts within the housing and an easily removable and replaceable photoionization chamber within the housing. The photoionization chamber includes a cathodic electrode and an anodic electrode which may be coated with a thin layer of material. The photoionization chamber and the associated cathodic electrode and anodic electrode are removable from within the housing as a unit. The photoionization chamber makes electrical connection with the contacts when seated within the housing regardless of the orientation of the photoionization chamber about an axis.

Abstract: A gas detection device is provided comprising an exterior housing in which an active pelement and a compensating pelement are disposed. The gas detection device further comprises a porous frit seated within a distal end of the exterior housing to separate the active pelement and the compensating pelement from the surrounding environment. The porous frit is adapted to prevent flashback into the surrounding environment while allowing movement of environmental gas through the porous frit to contact the active pelement and the compensating pelement. The gas detection device further comprises a flow guide for directing flow of environmental gas into the gas detection device disposed adjacent the exterior side of the porous frit. The flow guide comprises an inlet port through which a forced flow of environmental gas is pumped to pass through the porous frit and into the exterior housing in a direction generally parallel to the axis of the exterior housing.

Abstract: A personal sampling apparatus having multiple sampling ports for simultaneously taking a plurality of ambient air samples in parallel. Incorporated into the sampling apparatus is a regulator for enabling the apparatus to function with virtually any personal sampling pump. The regulator by being located immediately proximate to the sampling ports is able to provide independent vacuum flow rate control of each of the multiple sampling ports.

Abstract: A temperature compensator for gas meters is comprised of two serially connected bi-metallic elements extending between the tangent post and the drive shaft from the flow responsive element. The bimetallic elements are reversely oriented whereby each element responds to a given temperature change to produce movement in the same direction as the other with respect to the axis of the drive shaft.