For this type of pump, the barrel is put in the well to the designed depth with tubing. And then put the plunger into the barrel with sucker rod. Given the tubing size, the bore of the tubing pump is larger than that of the rod pump, so the pump rate is higher. According to seating mode, the rod pump can be divided into three types: THC pump (Stationary Heavy Wall, Cup Seating, Tubing pump), THM pump (Stationary Heavy Wall Mech. Seating, Tubing Pump) and THD pump.