body 10 or as illustrated in the figures a component 70 fixed in the bottom of said pump body 10 includes a tubular portion axially extending towards the inside of the pump body the lower end 56 of the axial tube 55 of the input valve seat 51 sealably cooperates with said tubular portion 80 in the examples illustrated in the figures this tubular portion 80 is part of the plunger tube 70 but forming this tubular projection 80 directly in the bottom of the pump body 10 may perfectly be contemplated also the lower end 56 of tube 55 sealably slides inside the tubular portion 80 but having this lower end of the tube 55 slide on the external wall of said tubular portion 80 may be contemplated the fact that tube 55 connected to the input valve 50 sealably cooperates with the plunger tube 70 results in that the return spring 5 may be positioned away from any contact with the product this may notably be the case if the tubular portion 80 is sealably assembled in the lower aperture of the pump body 10 this promotes the stability of the product when the spring is made in metal and generally prevents all the problems encountered with metal springs thus with a glass or plastic ball 59 the fluid product to be dispensed is no longer in contact with any metal component.