The negative pressure distributor is used to connect the negative pressure unit with the sand box. The negative pressure distributor distributes the vacuum generated by the negative pressure unit reasonably, and then distributes it to each required vacuum point. Ensure the negative pressure inside the sand box during pouring, and equip it with a regulating valve and pressure gauge. Through the regulating valve, ensure that the negative pressure inside the sand box meets the pouring requirements, ensure that the box does not collapse or spray back, and ensure safe production.