What is mortar pump the difference between single cylinder and double cylinder

[fusion_builder_container hundred_percent="no" equal_height_columns="no" menu_anchor="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" background_color="" background_image="" background_position="center center" background_repeat="no-repeat" fade="no" background_parallax="none" parallax_speed="0.3" video_mp4="" video_webm="" video_ogv="" video_url="" video_aspect_ratio="16:9" video_loop="yes" video_mute="yes" overlay_color="" video_preview_image="" border_size="" border_color="" border_style="solid" padding_top="" padding_bottom="" padding_left="" padding_right=""][fusion_builder_row][fusion_builder_column type="1_1" layout="1_1" background_position="left top" background_color="" border_size="" border_color="" border_style="solid" border_position="all" spacing="yes" background_image="" background_repeat="no-repeat" padding="" margin_top="0px" margin_bottom="0px" class="" id="" animation_type="" animation_speed="0.3" animation_direction="left" hide_on_mobile="small-visibility,medium-visibility,large-visibility" center_content="no" last="no" min_height="" hover_type="none" link=""][fusion_text] Single cylinder pressure fluctuation is large, double cylinder pressure fluctuation is small; Fluctuation little conveying distance long. [/fusion_text][/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]