For the calibration of the vacuum evacuation time of the vacuum vessel and the absolute pressure indication error of the test apparatus specified in JJF 2117-2024 Calibration Specification for Test Apparatus for Theoretical Maximum Specific Gravity of Asphalt Mixtures, Xiamen Jiangjing Technology Co., Ltd. has developed a compact vacuum pump and a high-precision digital absolute pressure gauge.The device can automatically generate vacuum and greatly improve work efficiency. Its compact design enables on-site metrological calibration of the density tester. It is equipped with a built-in fully automatic pressure source, a built-in high-precision pressure calibrator, a built-in rechargeable battery, and a built-in multi-stage filtration protection system, supporting full-automatic on-site calibration of pressure transmitters, pressure controllers, analog pressure gauges, digital pressure gauges, pressure switches and other instruments.