This small valve cover is set amidst a small field of access holes by the old Croton water gate at 138th Street and Convent Ave. It is unclear (to this writer) whether the CP refers to a company or to Corrosion Protection a proceedure where a small electric charge is added to steel pipes to protect from corrosion, and the anode needs to be checked and replaced periodically.
The simple design has two diamond badges that would make excellent spots for a company logo.
This cover is next to the former Croton Aqueduct gate house, which was decommissioned in 1984 and which has been converted into a small theater space. It is the only one I have come across.