Overview
The JZJS series Roots-Water Ring Vacuum Units are vacuum obtaining equipment primarily utilizing Roots vacuum pumps (also known as Roots booster pumps) as the main pump. They are equipped with a two-stage water ring vacuum pump as the preliminary pump, controlled by an electrically connected vacuum gauge and pressure gauge for automatic opening and closing, protection, and safety of the entire unit. Besides sharing certain characteristics of general Roots vacuum pump units, these units are particularly suitable for industrial processes involving a high amount of water vapor and corrosive gases, such as drying, dehydration, evaporation, distillation, and crystallization. Due to the water ring vacuum pump's lower ultimate vacuum compared to oil-sealed mechanical pumps, the ultimate vacuum of Roots vacuum pump-water ring pump units with a water ring vacuum pump as the preliminary pump is lower than that of Roots vacuum pump-oil-sealed mechanical pump units with an oil-sealed mechanical pump as the preliminary pump. The ultimate vacuum of this three-stage model is 25Pa, and that of the two-stage model is 400Pa, which is more than sufficient to meet the requirements of the aforementioned industrial processes.
Operating Principle and Structural Features
The JZJS series unit is primarily composed of two main parts: the pump section (suction section) and the power control section. The pump section of the JZJS three-stage unit is made up of two rotary vane vacuum pumps and one two-stage water ring vacuum pump in a three-stage series configuration. The two-stage water ring pump is referred to as the preliminary pump, the rotary vane vacuum pump connected to the suction vessel is called the main pump stage, and the single-stage rotary vane pump connected to both the preliminary and main pump stages is known as the intermediate stage. Removing the intermediate stage rotary vane vacuum pump would form the JZJS two-stage unit. The ultimate vacuum of the three-stage unit can be one order of magnitude higher than that of the two-stage unit, reaching 25Pa or higher.
Due to the fact that standard Roots vacuum pumps cannot be started under atmospheric conditions, they must be pre-evacuated to a vacuum at their exhaust end before starting. Therefore, a preliminary vacuum pump (referred to as the preliminary pump) must be installed at the outlet of the Roots vacuum pump. For the ZJS three-stage unit, the preliminary pump of the main pump stage is the intermediate stage, and the preliminary pump of the intermediate stage is a two-stage water ring pump. For the JZJX two-stage unit, the preliminary pump of the main pump stage is a two-stage water ring pump.
The suction speed ratio between vacuum pumps of different levels (the suction speed of the downstream pump compared to the upstream pump) should comply with a certain proportion. Considering the insufficient power and exhaust suction capacity of the upstream pump under high suction speed ratios, which can negatively affect the downstream vacuum pump. Generally, the suction speed ratio should not exceed 3, and a ratio of around 2 is preferable.
The Roots vacuum pump boasts excellent suction properties (with high flow rate at low pressure) and, when used as a secondary pump within the pump's ultimate vacuum range, it can always enhance the vacuum level by an order of magnitude compared to the primary vacuum pump (e.g., if the primary vacuum is 100 Pa, it can be increased to 10 Pa without the Roots vacuum pump, and so on). As there is no mechanical contact between the rotors and the pump cavity, lubrication is not required, resulting in significantly lower power loss than other types of mechanical vacuum pumps with the same flow rate. Moreover, due to the JZJS series being equipped with a two-stage water ring pump as its primary pump, it is particularly suitable for industrial processes with fixed corrosiveness and high moisture content.
Note: 1. The table above lists recommended standard models in the industry, which can also be customized for special user requirements.
2. Technical specifications for single pumps are detailed in each pump's performance parameters.
