Injector

**Steam Injector:**
– Common device for delivering water to steam boilers.
– Used in steam locomotives.
– Delivers cold water to a boiler against its own pressure.
– Operates using live or exhaust steam.
– Can use pressurized motive fluids like air.

**History and Design Parameters:**
– Invented by Henri Giffard in the early 1850s.
– Patented in France in 1858 and in the UK by Sharp, Stewart, and Company.
– Widely adopted for steam locomotives.
– Key design parameters include fluid feed rate, operating pressure range, vacuum pressure, and evacuation rate.
– Defines compression ratio and entrainment ratio.

**Lifting Properties and Operation:**
– Includes fluid inlet pressure requirements.
– Non-lifting injectors need positive inlet fluid pressure, while lifting injectors can operate with negative pressure.
– Dimensions of nozzles differ between lifting and non-lifting types.
– Operation involves a body filled with secondary fluid, utilizing the Venturi effect.

**Problems and Vacuum Ejectors:**
– Issues like vibration, warm incoming water, overheating, and erosive wear.
– Vacuum ejectors used in continuous train braking systems.
– Steam locomotives employ ejector technology for braking.
– Vacuum brakes replaced by air brakes in modern trains.
– Ejector exhaust directed to the smokebox to assist in fire draught.

**Modern Uses and Well Pumps:**
– Injectors used in industrial applications, jet pumps in nuclear reactors, eductors in ships, and aspirators in laboratories.
– Jet pumps extract water from wells, with shallow and deep well pump distinctions.
– Electrical submersible pumps replacing jet pumps.
– Various construction materials used for injectors and ejectors.