Patent GB-521234-A (GB)
Title: Improvements in or relating to delivery apparatus for liquid and semi-liquid substances
IPC: F16N27/00
Filed: 1938-11-03
Abstract: 521,234. Pumps for delivering lubricant &c. TRIER BROS, Ltd., TRIER, F. N., and CROTHERS, P.F. Nov. 3, 1938, No. 14074/39. Divided out of 505,248. [Class 102 (i)] [Also in Group XXIX] Apparatus for delivering lubricant, or other liquid or semi-liquid substance, comprises a main cylinder A divided by a free piston A<SP>5</SP> into two chambers, one chamber having inlet and delivery ports A<SP>2</SP>, A<SP>4</SP> for for the lubricant, whilst operating liquid under pressure is delivered at a desired rate to, and withdrawn from, the other chamber by two pumps D<SP>1</SP>, D<SP>2</SP> of smaller and larger capacity respectively and driven mechanically from a common source of power, valve apparatus which in one position connects the delivery passage of the smaller capacity pump to the operating liquid chamber of the main cylinder and renders the larger capacity pump inoperative, and in another position connects the suction passage of the larger capacity pump to the operating liquid chamber of the main cylinder, and means for automatically moving the valve apparatus from one position to the other as the free piston reaches each end of its stroke. In the form shown in Figs. 1 and 2, the piston A<SP>5</SP> slides upon a rod A<SP>6</SP> provided at its upper end with an abutment A<SP>7</SP> engageable with a stop A<SP>9</SP>, and at its lower end with a valve B forming a second abutment, springs A<SP>8</SP> being disposed between the piston and the abutments. The valve B has annular recesses B<SP>1</SP>, B<SP>2</SP> communicating with bores which open respectively into the reservoir base C and the lower end of cylinder A, and two grooves B<SP>3</SP> co-operating with spring-pressed balls B<SP>4</SP>. The latter, together with the springs A<SP>8</SP>, cause a snap action of the rod A<SP>6</SP> at each end of the stroke of piston A<SP>5</SP>. The pump D<SP>1</SP> has a suction part E connected by a pipe E<SP>1</SP> and a sight feed E<SP>2</SP> with the base C, and a delivery port F, its delivery being controlled by a spring-pressed dummy piston D<SP>5</SP> whose position of rest is determined by moving a spring-pressed housing D<SP>8</SP> by means of a screw D<SP>9</SP>. The pump D<SP>2</SP> has two suction ports G, G<SP>1</SP> and a single delivery port G<SP>2</SP> leading into the base C. In the lowered portion of rod A<SP>6</SP>, as shown, the pump D<SP>1</SP> delivers operating liquid to the cylinder A to raise the piston A<SP>5</SP> comparatively slowly, whilst the pump D<SP>2</SP> merely circulates the liquid within the base C. In the raised position of the rod A<SP>6</SP>, the pump D<SP>1</SP> merely circulates the liquid within the base C, whilst the pump D<SP>2</SP> comparatively quickly withdraws the liquid from the cylinder A into the base C. In the form shown in Fig. 4, the rod A<SP>6</SP> and valve B are omitted and the valve apparatus comprises a changeover valve H slidable in a cylinder H<SP>4</SP> and provided with grooves H<SP>1</SP>, H<SP>2</SP> co-operating with spring-pressed balls H<SP>3</SP>. The latter, together with the pressure of the operating liquid acting on the ends of the valve H at each end of the stroke of the main piston, cause a snap action of the valve H. The pump D<SP>1</SP> has suction and delivery ports E, F, and the pump D<SP>2</SP> suction and delivery ports G, G<SP>2</SP>. The port G<SP>2</SP> communicates with a closed sump or reservoir in the form of an air bottle J which leads to one end of the cylinder H<SP>4</SP> and to a pressure accumulator J<SP>1</SP>. Between the other end of the cylinder H<SP>4</SP> and the main cylinder A are two spring- pressed non-return valves K, K<SP>1</SP> and a second pressure accumulator K<SP>2</SP>. The action of the pumps is similar to those of the first form. except that, with the valve H in the right-hand position, both pumps withdraw operating liquid from the cylinder A into the reservoir J.