Pressure resistant light engine

A photoreactor assembly comprising (i) a light source arrangement, (ii) a photochemical reactor, and (iii) a reaction chamber pressure compensating system;

• wherein:
• the light source arrangement comprises a light chamber hosting a plurality of light sources, wherein the light sources are configured to generate light source radiation selected from one or more of UV radiation, visible radiation, and IR radiation;
• wherein the light chamber has a light chamber pressure PL;
• the photochemical reactor comprises a reactor chamber configured to host a first fluid to be treated with the light source radiation;
• wherein the photochemical reactor comprises a light transmissive window that is transmissive for the light source radiation;
• wherein the light transmissive window separates the light chamber from the reactor chamber;
• wherein the plurality of light sources are configured to irradiate at least part of the reactor chamber via the light transmissive window;
• wherein the photochemical reactor comprises a spinning disk reactor, wherein the spinning disk reactor comprises a disk at least partly configured in the reaction chamber;
• and
• the reaction chamber pressure compensating system is configured to compensate for a reactor chamber pressure PR in the photochemical reactor on the light transmissive window;
• and
• wherein the reaction chamber pressure compensating system comprises a pressure control system;
• wherein the photoreactor assembly further comprises a control system, wherein the control system is configured to control with the pressure control system a pressure difference ΔP between the light chamber pressure PL and the reactor chamber pressure PR;
• wherein the control system is configured to maintain the pressure difference ΔP below |+/−0.2*PR|.