Storm drain filter system

A method of filtering drainage water in an existing storm drain of the type having a collection box with a water inlet for receiving drainage water and an outlet for carrying filtered water, comprising the steps of:

• assembling plural parts of a multipart frame in the collection box;
• forming a filter compartment using said multipart frame within the collection box in a position so that drainage water is routed from the collection box inlet into the filter compartment;
• providing the filter compartment with a filter medium for filtering the drainage water;
• and
• forming an overflow within said collection box by spacing a filter sidewall from a wall of the collection box so that when the filter compartment is full, the drainage water from the inlet flows over the top of the filter sidewall and downwardly in the space between the filter sidewall and the collection box wall to the outlet of the collection box.

A filter system for use with a storm drain of the type having an existing collection box with an inlet for drainage water and an outlet for carrying filtered water, comprising:

• a frame having a bed and a back removably attached together and being of a size for insertion through said inlet into said collection box and assembled therein, said frame further including legs removably attached to said bed for supporting the frame above a floor of the collection box;
• a filter supported by the floor and back of the frame for filtering objects carried by the drainage water, said filter being removable from the collection box without removing the frame;
• and
• means for securing said frame in a predetermined position within the collection box.

A filter system for a storm drain of the type having a collection box with an inlet for drainage water and an outlet for filtered water, comprising in combination:

• a collection box;
• a frame disposed in said collection box and being expandable to fit edge-to-edge within an internal lateral dimension of the collection box;
• filter means for removing objects carried with the drainage water so that filtered water can flow out said outlet, said filter means being supported by said frame;
• and
• said frame and said filter means being arranged in said collection box so as to form a filter compartment for holding objects removed from the drainage water and to allow filtered water to flow through the filter means and out of said outlet.

A storm drain filter system, comprising in combination:

• a vaulted collection box of unitary construction having opposing sidewalls, a front wall and a back wall, all formed integral with a bottom and a top of the collection box, said collection box having a frontal inlet opening comprising an elongate rectangular opening having a width substantially greater than a height thereof, and an outlet located at a bottom portion of the collection box;
• a portable filter frame being of a size for insertion in the collection box via the inlet opening, and extending substantially from one opposing sidewall to the other sidewall of the collection box, and abutted against the front wall of the collection box below the inlet opening;
• said filter frame having an upright back portion spaced forwardly from the back wall of the collection box, said upright back portion of the filter frame and said front wall of the collection box defining a filter compartment for receiving drainage water from the inlet opening and directing the drainage water through a filter medium;
• said filter medium comprising a rigid filter medium disposed on a filter frame portion defining a bottom of said filter compartment, said rigid filter medium having apertures functioning to filter the drainage water;
• an overflow area defined by a space between the upright back portion of the filter frame and the back wall of the collection box;
• and
• a plurality of supports for supporting the filter frame above the floor of the collection box so that the drainage water first flows through the rigid filter medium and when said filter compartment is full of debris, the drainage water flows over the upright back portion of the filter frame down the overflow area and is carried out of the outlet of the collection box.