The dispensing piston is the most important part of the cream whipper and is responsible for dispensing the whipped cream. It is the part of the siphon head which receives the most stress. The decorator tip is placed on the end of the piston.

In older siphons, most of the piston was made of metal, with only the part inside the head made of plastic. For simplicity, this type is commonly known as a “metal dispensing piston”. The new design of the dispensing piston is incompatible with the old one, has part number A66 and is made fully of plastic.

Whipped cream dispensing piston (A37)

The dispensing system consists of three parts: the piston itself, a smaller sealing ring at the top (O-ring) and a larger sealing ring at the bottom.

Sealing rings of the dispensing piston

Sealing rings

On the exploded drawing of the instruction manual for the siphons, both seals are marked with the part number A16, which is a printing error in my opinion. In the text of the manual the lower O-ring has part number A56. The two O-rings are obviously different sizes.

For replacing the smaller sealing ring, Szász Ltd. recommended the use of a 6×3 mm O-ring. Unfortunately, the ones currently on the market are not very flexible, so it is very difficult to pull them into the right place on the dispensing piston. After installation, I found that the dispensing handle is very difficult to move even after lubricating the seals with silicone grease. After a long run-in, this improves somewhat.

Instead of the larger sealing ring, I use a 9.3 x 2.4 mm silicone O-ring bought from a gasket shop, and it works perfectly.

Cleaning

The dispensing piston is the most difficult part of the cream whipper to access. Thorough cleaning has been neglected on all the examples I have seen in my practice, making it the most contaminated part of the device. The instruction booklet, and common sense tells us that the piston should always be removed after the cream has run out and thoroughly cleaned of greasy dirt. Cleaning requires a small brush. I use the product “9213 Cleaning Brush” from the company LISS Zrt.