TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The bottom shell of the purifier is provided with a spring clamp and a location protruding table for mounting a linear biogas pressure gage and a columnar pressure meter. The pressure meter is fixed on the protruding table by using bolt through the installation hole on the pressure meter. The bottom shell of the purifier is formed with two screw holes for mounting the desulfurizing bottle. The nuts are embedded in the screw holes. The desulfurizing bottle is formed with a location installing gap to mount the desulfurizing bottle on the bottom shell through the bolt. The desulfurizing bottle is U shaped. The lower end of the bottle opening is formed with an external thread. The external thread is matched with the inner bottle cover. The inner bottle cover is placed with the rubber sealing ring. The outer bottle cover is formed with the internal thread. The rubber sealing ring is pressed on the bottle opening to seal the bottle opening when the bottle cover is screwed. The bottle shoulder and the bottle cover of the desulfurizing bottle are respectively provided with location marks for indicating the position that reaches the sealing requirement when the bottle cover is screwed. The upper ends of the plastic throttle pressure adjusting valve and the three-way connecting plug are connected with a gas conveying pipeline. The lower ends of the plastic throttle pressure adjusting valve and the three-way connecting plug are movable plugs. The connecting plug is in the form of three-way port, where one port is used for connecting the biogas pressure gage. The two sides of the upper end of the U-shaped desulfurizing bottle formed with the bell and spigots are respectively located on the gas inlet and the gas outlet. The gas input port of the biogas pressure gage is connected with the connecting plug by using the rubber hose, and the two parts are fixed by using the special nylon binding belt. The mask of the purifier is formed with a window of the biogas pressure gage. The window is rectangular for linear biogas pressure gage, and is circular for pressure meter. The mask is formed with a conical concave hole at the position corresponding to the plastic throttle pressure adjusting valve to expose the knob of the valve. The circumference of the knob hole is 360 degrees and is distributed with closing and opening valve (0-10 in number). The upper and lower symmetrical positions, and the left and right symmetrical positions of the mask of the purifier are provided with spring buckles. The spring buckles firmly block the mask on the bottom shell when the mask of the purifier is buckled.