Abstract: A resilient seat gate valve is provided with a housing having an opening for receiving the operating stem for the valve and a cover with a seal for the cover to the housing opening comprising a step peripheral surface and an angled surface located interiorly of the valve housing opening; the cover is provided with a locking mechanism for drawing the opening peripheral surface against the angled surface of the housing lip to compress the seal carried by the peripheral surface of the cover and to effect the attachment of the cover in place without bolts or screws; the valve disc is provided with side edges covered by an elastomer and protected with a fully enclosing, replaceable cap to prolong the life of the valve disc by protecting the elastomer coating from abrasion; a dumbbell dirt and fluid pressure seal O-ring arrangement is provided between the cover and lip of the housing to facilitate insertion and positioning of the seal during installation of the cover.